CA2279877C - A navigation/guidance system for a land-based vehicle - Google Patents
A navigation/guidance system for a land-based vehicle Download PDFInfo
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- CA2279877C CA2279877C CA002279877A CA2279877A CA2279877C CA 2279877 C CA2279877 C CA 2279877C CA 002279877 A CA002279877 A CA 002279877A CA 2279877 A CA2279877 A CA 2279877A CA 2279877 C CA2279877 C CA 2279877C
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- Prior art keywords
- vehicle
- navigation system
- attitude
- antenna
- heading
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/42—Determining position
- G01S19/45—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
- G01S19/47—Determining position by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
- G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
- G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
- G01C21/165—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation combined with non-inertial navigation instruments
- G01C21/1652—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation combined with non-inertial navigation instruments with ranging devices, e.g. LIDAR or RADAR
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/50—Systems of measurement based on relative movement of target
- G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
- G01S13/60—Velocity or trajectory determination systems; Sense-of-movement determination systems wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
Abstract
A navigation/guidance system (10) uses a dead reckoning navigator with periodic GPS fixes to correct the drift of the inertial system. The navigation system (10) primarily uses speed sensed by Doppler radar (30) and attitude and heading sensed by a set of gyros (24). The navigation system (10) uses various processes to compensate for any sensor errors. The system uses attitude data to compensate for GPS leverarm errors. The system can be used on a land-based vehicle (60) to economically and accurately provide navigation data.
Description
' CA 02279877 1999-08-06 TITLE: A NAVIGATION/GUIDANCE SYSTEM FOR A LAND-BASED
VEHICLE
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to inertial navigation systems. More particularly, though not exclusively, the present invention relates to an inertial navigation/guidance system using a radio navigation receiver to correct the navigation errors.
PROBLEMS IN THE ART
Differential global positioning system (DGPS) based guidance systems for airborne application of agrochemicals has met with huge success and it follows that this technology could be used with ground rig applicators if certain technical problems can be overcome. The primary differences between air and ground application processes are associated with the operators view of the land and the operational dynamic environment.
During airborne applications, the pilot generally has a large part of the area involved to be sprayed in view and the GPS antenna (mounted on top of the canopy) follows a relatively straight line when in an application swath. This provides for the required cross track position stability to obtain a well controlled application process.
With ground rig applicators, such as tractors or floaters, the operator may have a limited view of the involved spray area and depending on the size/shape of the field and of the local ground cover it can be very difficult to determine where the previous swath coverage ends in order to proceed with the ensuing swath. A GPS antenna mounted on top of the ground vehicle (where it would be exposed to the GPS satellites) will experience large attitude excursions as the rig swaths the field. This results in GPS derived cross track position excursions relative to the vehicle ground track which would contaminate any attempt to parallel a defined field line. It can therefore be seen that there is a ~ SUBSTITUTE SHEET (RULE 2B) need for a better navigation/guidance system for use with a ground-based vehicle.
There is a need for a solution to various problems relating to ground rig applicators such as tractors and floaters. These ground rig applicators have several disadvantages. Since the application of agrochemicals is a seasonal process t3-4 months per year), the workers hired to operate the floaters are seasonal workers. As a result, the seasonal workers are often inexperienced or unreliable in the operation of the floaters. This increases the probability that the operator will skip areas of the field or apply double coverage to overlapping areas. These problems cost the seller of the chemicals and the farmer thousands of dollars. A typical floater will cost $100,000 and will apply $500,000 - $1 million dollars worth of chemicals per year.
It can therefore be seen that efficient operating of a floater is very important. Typical prior art floaters are guided through a field by following a trail of foam markers which are marked on the field on the previous swath. As a result, there is a lot of room for human error and the floaters cannot be operated at night. A need can therefore be seen which would allow the floaters to operate accurately day or night throughout the season. Such a solution would allow a chemical applier to operate half as many machines.
An accurate, real-time inexpensive navigation/guidance system would remedy these problems.
Various prior art navigation systems for ground-based vehicles have several disadvantages. Systems using Doppler radar will encounter errors with the radar. Similarly, gyros will encounter drift errors which will continue to increase unless the drift error is corrected. Gyros that are inexpensive enough to be feasible to use may have drift rates high enough to make them unusable. For example, a typical inexpensive gyro sensor may have a drift rate uncertainty as high as 3600° per hour which makes the gyro unusable for most applications. As a result, gyros have good short term SUBSTITUTE SHEET (RULE 26) characteristics but bad long term characteristics as the drift error becomes larger ~s t.ime goes on.
When navigat=ing using dead reckoning you need a very high fidelity heading measura:ment which ria:~ not been achieved adequately using low costs sensors.
Various prior ar; syst:ems navigating by GPS also have disadvantages. Prior art systems using GPS use GPS as the primary navigator. T:n.i.s intens.ifi_e:~ the problerns found. with GPS. A GPS position ca l.c.ulation has a lag time. As a result, the position solnztion provided by a GPS receiver_ tells a user where the vehicle was a moment ago not in real time. Another problem with GPS systt~rns are the errors resu Lting from the antenna lever arm problem. A GPS antenna typically is a certain dist<~nce away frc>m the c:~P.S receiver. Since the GPS
1S antenna is the collection point of the GPS signals received, the position solution wi.l.l. not ~accurat:ely describe the position of the GPS receiver or some other reference point.
If the geometrical di.:>tarvce between the GPS sveceiver or reference point and the GPS antenna is known, the position of the reference point ma:ry be calculated. However, as a ground based vehicle travels over uneven terrain such as terraces, slopes, ruts, bumps, E:et.e., the actual. position of the GPS
antenna cannot be determined resulting in erratic GPS position solutions.
2S Most prior art attempts to use a GPS navigation system attempted to deal withr problems by correcting GPS drift and lag time. However no prior art s=stem navigating by GPS has achieved the high accuracy and r_ea1 time soli_ztions required for applications requiring a high level of accuracy. The 3G prior art attempts ha~;e n.ot prcmicled an adeguate solution because GPS does not provide a continuous navigation solution.
A GPS system will upd~:<te its posit_.ion periodically, not in real time, and a lag time is still. involved. Another problem with a GPS system is the possibility of a signal dropout of the satellite signals. The accuracy of a GP;:~ system is also limited due i~o the er:r.c:~rs caused by the ionosphere. Another problem with GPS systems is that altitude data provided by a ~~ GPS receiver is not pre~,..ise.
Another problem ~~ait.h ~:~PS syst.erris is that a GPS system cannot accurately supply guidan::e data for_ a curved path.
This problem relates i-:o the lack t:i.rne involved w.i.th GPS. A GPS
system can only do linear interpolation of GPS position solutions whi.~~h is inadequate for navigating a curved path. A
GPS system also will root provide high quality heading information. Finally, the altitude calculated by a GPS
receiver is inaccurate and unusable for certain applications.
Publication WO 91.!09315 discloses an integrated vehicle positioning and navigation system, apparatus and method. It describes improving accuracy of position est:imat.ion by combining GPS, inertial and odometer data, and by predetermined weighting of .such data, outputting a position estimate. It discloses the use of expansive components and a complex system that tries to reduce the problems with the various components and r;hei_r acco.zracy.
Publication WO 95/:L~3432 is entii=led "Field Navigation System". It describes what it calls a dead z:eckoning navigation system, usi:vg data from a compass, GPS, and a radar gun as inputs to a posi.t~ion computer. Imprcved accuracy of estimated pos=ition is t:ai.tght by pre-Loading a map into the system so that a cross cheek of the estimated calculated position can be made to the pre-:Loaded map. "'his adds complexity and the burc:ler~ of having a pre-loaded map for the area the vehicle is in.
FEATURES OF ~'HE INVENTION
A general feature <at the present invention is the provision of an inert.~..al navigation/guidance system.
A further feature c~t the yresent inventi..on is the provision of an inertial navigat:ion/guidance system for use on a land-based vehicle.
A further featurE:~ of the present invention is the provision of an inertial navigau~ion/guidance system that senses the attitude ofthe vehic~lEa.
A further feature of the present invention is the provision of an inertial. navigat~ion/guidance system which uses a radio navigation rec:e:i per 'to <:orrect the d.ri.ft errors of the inertial system.
A further. feature o.f the present invention is the provision of an inertial nav:igat:icn/~~u.ie~ance system which uses inexpensive sensors to achieve :~ highly accurate result.
A further feature ofi the present :invention is the provision of an inerti.:~1 attitude determination system which is stand alone.
A furtherr feature of the present: invention is the provision of <~n inertial navigation/guidance system which uses gyro information to compute the attitude and heading of the vehicle and a pos:i.tion <:v~ange serusor to sense the speed of the vehicle.
A further_ feature of the present. invention is the provision of yin inerti<;~=L. navigati.on/guidance ~7ystem which uses accelerometers to measure the pitch and roll of the vehicle to refine the sensed attitude of the vehicle.
A further feature of the present invention is the provision of an inertial navigation/guidance system which includes software to control the functions of the system.
A further feature of the present invention is the provision of an inertial navigation/guidance system which uses the sensed attitude of the vehicle to determine the position of the radio navigation antenna in order to correct l0 the lever-arm error.
A further feature of the present invention is the provision of a system for use on a boat or ship.
A further feature of the present invention is the provision of a system which is part of a surveying system.
These as well as other features of the present invention will become apparent from the following specification and claims.
SVI~11RY O~' Tg8 INVENTION
The navigation and guidance system of the present invention provides accurate navigation data in real time using a dead reckoning navigator with periodic radio navigation fixes to correct for the drift of the inertial system. The system senses the speed, heading and attitude of the vehicle to determine a position of the vehicle. An external position reference provided by the radio navigation system is used to correct any error in the determined position.
The system is capable of correcting for the radio navigation antenna lever arm errors by using the attitude of the vehicle. The system may optionally be used on a ground or water based vehicle to provide navigation data and guidance commands to an automatic steering system. The system of the present invention may also be used on a agricultural vehicle to guide the vehicle through a field in a number of ways.
An aspect of the invention is to provide a method of navigating a non-airborne vehicle comprising the steps of: providing a position change sensor; sensing the speed of the vehicle using the position change sensor; providing an angular change sensor;
sensing the heading and attitude of the vehicle using the angular change sensor; providing an accelerometer; correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle; providing a radio navigation system;
storing positions of the vehicle each relative to a given point in time; determining an external position reference for a given point in time using data from the radio navigation system;
and correcting any error in determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time. The position change sensor may be comprised of a Doppler radar.
The angular change sensor may be comprised of gyro. The accelerometer may be comprised of a tilt sensor or an inclinometer. The radio navigation system may be comprised of a GPS system, a LORAN system or a GLONASS system. The method may further comprise the steps o~ providing a radio navigation antenna for use with the radio navigation system, said antenna having a known location relative to a reference point on the vehicle; determining the position of the radio navigation antenna based on the attitude of the vehicle and the known location of the antenna relative to the reference point; and determining the external position reference using the position of the radio navigation antenna. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or controlling location and travel of trains.
Another aspect of the invention is to provide a navigation system for a non-airborne vehicle comprising: a position change sensor for sensing the speed of the vehicle; a set of gyros for sensing the attitude and heading of the vehicle; a set of accelerometers for sensing the forces acting on the vehicle; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said vehicle at a known location relative to the vehicle;
and a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of: correcting the sensed attitude of the vehicle using the 6-a sensed forces acting on the vehicle; determining the velocity of the vehicle using the sensed speed, heading and attitude of the vehicle, determining a first position of the vehicle by integrating the determined velocity; storing said first position of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the vehicle and the known location of the antenna relative to the vehicle, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored first position of the vehicle for the same point in time. The position change sensor may be comprised of a Doppler radar. The set of gyros may be comprised of two gyro sensors or three gyro sensors. The radio navigation system may be a GPS system. The radio navigation system may further comprise a DGPS receiver. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or a guidance system port for providing data to a vehicle steering system. The data provided to a vehicle guidance system may relate to the vehicle position and heading. The data may also relate to a desired path.
The data may comprise a steering command signal. The data provided to a vehicle guidance system may include the cross track error and heading error.
Another aspect of the present invention is to provide a method of navigating a land-based agricultural vehicle through a field comprising the steps o~ sensing the speed of the vehicle; providing an inertial sensor system; sensing the head and attitude of the vehicle using the inertial sensor system; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
storing position of the vehicle each relative to a given point in time;
providing a radio navigation system; determining an external position reference for a given point in time using data from the radio navigation system; producing true position data by correcting any error in the determined position of the vehicle using the external position reference and comparing it to the stored position of the vehicle for the same point in time; and using the true position data to accurately navigate through a field. The method may further comprise the steps of: providing a radio navigation system antenna coupled to the vehicle at a known location relative to the vehicle; determining the position of the antenna based on the attitude of the vehicle and the location of the antenna relative to the 6-b vehicle; and refining the determined external position reference based on the determined position of the antenna. The position change sensor may be comprised of a Doppler radar. The heading and attitude may be sensed using an angular change sensor.
The angular change sensor may be comprised of a plurality of gyros. The method may further comprise the steps o~ sensing the acceleration caused by the vehicle;
using the sensed acceleration caused by the vehicle to refine the determined position of the vehicle.
The radio navigation system may be comprised of a GPS. The method may further comprise the steps of determining the cross track error and heading error based on the true position data and a desired navigation path, or the step of creating a guidance command signal based on the determined cross track error and heading error, or the step of displaying information based on the guidance control signal, or the step of displaying information based on the true position data. Further, the land based agricultural vehicle may comprise a chemical sprayer. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or controlling location and travel of trains.
Another aspect of the invention is to provide a method of compensating for a radio navigation system antenna lever arm for a non-airborne vehicle comprising the steps of providing a radio navigation system antenna having a known location relative to a reference point on the vehicle; providing an inertial system for sensing the angular changes of the vehicle; determining the attitude of the vehicle using data from the inertial system; and determining the position of the radio navigation system antenna based on the attitude of the vehicle and the known location of the radio navigation system antenna relative to the reference point.
Another aspect of the invention is to provide a navigation system for a tractor comprising: a position change sensor for sensing the speed of the tractor; a set of gyros for sensing the attitude and heading of the tractor; a set of angular change sensors for sensing the pitch and roll of the tractor; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said tractor at a known location relative to the tractor; a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of: correcting the sensed attitude of the tractor using the sensed pitch and roll of the tractor; determined the velocity of the tractor using the sensed speed, 6-c heading and attitude of the tractor, determining a first position of the tractor by integrating the determined velocity, storing said first positions of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the tractor and the known location of the antenna relative to the tractor, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored position of the vehicle for the same point in time;
an output port connected to said processor for providing data to a tractor guidance system. The navigation system may further comprise a user perceivable display connected to said processor for displaying information. The display may be comprised of a light bar mounted on the tractor. The data may be comprised of the cross track error and the heading error. The tractor guidance system may be comprised of an automatic steering system. The data may be comprised of guidance commands for the automatic steering system. The navigating may comprise surveying or mapping of an area.
Another aspect of the invention is to provide a method of navigating a moving non-airborne vehicle comprising the steps of: (a) sensing the speed of a vehicle;
(b) sensing the heading and attitude of the vehicle from a known initialization position using an inertial sensor system having inherent drift that increases over time; (c) estimating in real time the position of the vehicle for discrete points in time based on steps (a) and (b); (d) storing the estimates correlated to the discrete points in time; and (e) correcting error between estimated position and actual position by periodically determining actual position correlated to discrete points in time of the vehicle, comparing a stored estimated position with an actual position for the radio navigation system, and adjusting estimated position if the comparison falls outside a predetermined range; thus periodically producing real-time true position data for navigation of the vehicle by correcting for the inherent drift of the inertial sensor system, by periodically, if needed, comparing past estimated and past actual position and adjusting, if, needed, therebetween.
The navigating may comprise autonomous steering of the vehicle. The navigating may comprise surveying or mapping of an area.
6-d 8RI8F DESCRIPTION OF TH$ DRAi~IINGS
Figure 1 shows a block diagram of the primary hardware elements of the navigation/guidance system of the present invention.
Figure 2 shows a functional block diagram of the attitude/heading portion of the present invention.
Figure 3 shows a functional block diagram of the position correction function of the present invention.
Figure 4 shows a functional block diagram of the dead l0 reckoning navigation function of the present invention.
Figure 5 shows a functional block diagram of the guidance function of the present invention.
Figure 6 shows a tractor using the system of the present invention.
Figure 7 is an aerial view of a field being worked by the tractor shown in Figure 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODII~NT
The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all alternatives, modifications, and equivalences which may be included within the spirit and scope of the invention. While the present invention is described as being used on a land based vehicle, it is intended that the invention cover other applications.
Also, the term land-based vehicle is meant to include vehicles on the ground or in the water, "land-based" is meant only to distinguish from airborne applications.
The navigation/guidance system of the present invention is a dead reckoning navigator which uses periodic GPS fixes to correct the drift of the inertial system. The system uses GPS antenna attitude compensation to improve the accuracy of the GPS fixes. The system primarily uses speed sensed by Doppler radar and attitude and heading sensed by a set of gyros. As discussed above, systems using a Doppler sensor and gyros have the problem of errors in the sensors. In addition, in order to use inexpensive sensors, very large errors are encountered. The system uses various processes to compensate for the erro-rs. The heading sensed by the gyros is aided by a magnetic heading compass and a GPS receiver.
The speed sensed by the Doppler radar is also aided by the GPS receiver. The system also uses accelerometers to improve the accuracy of the system. A set of horizontal accelerometers measure the roll and pitch of the vehicle.
This is used to provide the attitude integration algorithm (discussed below) with the vehicle horizontal rotations to more accurately calculate the attitude and heading.
Figure 1 shows the primary hardware elements of the inertial navigation/guidance system 10 of the present invention. The system 10 is comprised of a personal computer (PC) 12 which includes a CPU, memory and input/output electronics. Although the embodiment shown in the drawings shows a personal computer, the invention.could use a processor circuit that includes a CPU, memory, and input/output electronics on a single processor card. A GPS
receiver 14 plugs directly into an open°PC expansion slot.
20~ Any GPS receiver suitable for use with the present invention may be used, however the preferred GPS receiver is the NovAtel GP5 receiver card #9518. Alternatively, the system l0 could simply have a connector that would receive GPS data from any existing GPS receiver. Any other type of radio navigation system or combination of systems could be substituted for the GPS system such as LORAN, GLONASS, etc.
A keyboard or keypad 16 is connected to the PC 12 and is used as a user interface to input data or control the system 10.
A display unit 18 is also connected to the PC 12. The display unit 18 is used to display various information to a user. The display unit 18 could take on many forms, but is preferably comprised of a CRT display. The display unit could even be comprised of a display screen that shows the operator a graphic of a field or portion of the field and could indicate where the vehicle has been and where it is going. All'sensor input data to the PC 12 will be digital serial. If any of the selected sensors provide only analog outputs, A/D converters will be used where required to obtain the appropriate input data formats. Also shown in Figure 1 is a block diagram of the power supply circuit used by the present invention. The power supply circuit includes a 12 volt battery 32, a voltage converter 34 and a power supply 36. The power supply circuit provides the system 10 with 110 volts AC and a regulated DC voltage.
A portable DGPS receiver 20 is also connected to the PC
12. The DGPS radio receiver 20 receives DGPS data for use by the PC to overcome the effects of Selective Availability (SA) as well as other imperfections in the time-coded signals broadcast by the NAVSTAR satellites. The use of DGPS
provides a more accurate location solution than GPS alone.
The DGPS radio receiver 20 may be any type of DGPS receiver suitable for use with the present invention but is preferably the Smartbase model number 10, manufactured by Premier GPS
Inc. Also note that the present invention would work without using DGPS, although the accuracy may be less. One alternative to the preferred embodimentyis to use a receiver that uses a combination of GPS and GLONASS signals to produce a more accurate radio navigation system.
A GPS antenna 22 is connected to the GPS receiver 14 to provide the GPS receiver 14 with GPS signals from the NAVSTAR
satellites. The GPS antenna 22 acts as the collection point for GPS signals received by the GPS receiver 14. The GPS
antenna 22 is mounted to the host vehicle at a known location such that the location of the antenna 22 is always known relative to the GPS receiver 14 or some other reference point.
As shown in Figure 1, a number of sensors are also connected to the PC 12. Three rate gyros 24, three accelerometers 26, and a magnetic heading compass 28 axe connected to the PC 12 to provide the system with various data. Preferably, the.gyros 24, accelerometers 26 and the magnetic heading compass 28 are assembled together in a single unit. A position change sensor 30, preferably comprised of a Doppler radar is also connected to the PC 12 to provide the system with speed data. Although the preferred embodiment uses three each of the gyros 24 and accelerometers 26, more or less could be used. The choice of using two or three accelerometers depends on such factors as the level of accuracy desired, the application of the system, and the sophistication of the Kalman filter, etc. The gyros 24 act as angular change sensors, so therefore, any device with the same function could be substituted for the gyros 24.
The preferred gyros are the model ENV-05H-02 manufactured by Murata Erie Co., Ltd. Similarly, the accelerometers 26 could be substituted by an equivalent device such an inclinometer, tilt sensors, etc. The preferred accelerometer is the model 02753-O1 manufactured by Lucas Control System Products. The magnetic heading compass could also be substituted by any other heading sensor, for example, a fluxgate compass. The preferred magnetic heading compass is the model C100 manufactured by KVH Industries, Inc. Also note that the magnetic heading compass 28 is optional. Depending on the sophistication of the Kalman filter and other factors, the magnetic heading compass 28 may not be needed by the system.
The Doppler radar 30 functions as a position change sensor, so therefore any equivalent device could be substituted for the Doppler radar such as an odometer or any other device used to derive the vehicle speed. The preferred Doppler radar is the model Radar II manufactured by Dickey-John.
Figure 2 shows a functional block diagram of the attitude/heading portion of the invention. The navigation/guidance system 10 uses software which performs the functions described and outlined in the figures. As described below, the attitude integration algorithm 42 uses the angular rates from the gyros 24, horizontal accelerations from the horizontal accelerometers 26, and heading and attitude error estimates from the other sensors to calculate a value for the vehicle s attitude (pitch and roll) and heading. The attitude and heading are primarily sensed by the gyros 24. The various sensors are used together as shown in the figures to obtain a more accurate value for attitude (pitch and roll) and heading. The data from the gyros 24 ~.s applied the gyro compensator function 40 which applies constant values such as a scale factor, misalignment and fixed bias to the data and also applies changing values such as an estimated dynamic bias to the data. The data is then provided to the attitude integration algorithm 42 to calculate the attitude and heading. The horizontal accelerometers 26 provide data to the accelerometer compensation function 46 which applies constant values such as scale factor, bias, and misalignments to the data. The compensated data from the accelerometers 26 is then provided to a direction cosine matrix (shown in Figure 2 as the body to navigation frame transformation function 48) and a platform leveling/damping function 50. The yaw attitude is slaved to the magnetic heading reference supplied by the magnetic heading compass 28. This, along with data from the GPS position are used by a blending filter 44 to provide a heading error estimate to the attitude integration algorithm 42. A pitch and roll error estimate is also provided to the attitude integration algorithm 42. The pitch and roll error estimate is derived from data from the Doppler radar 30, the horizontal accelerometers 26, and the gyros 24.
The attitude, heading and corresponding time are saved in a data table for interpolation to the GPS data time. This interpolated data is required to provide position corrections to the GPS position fix (see discussion of Figure 3 below) for use in the dead reckoning navigation function shown in Figure 4 (discussed below).
Figure 3 is a block diagram of the position correction function. As described above, the GPS receiver 14 is connected to the GPS antenna 22 to receive GPS data signals from the NAVSTAR satellites. The GPS receiver 14 also receives DGPS data from the DGPS radio receiver 20 to improve the GPS accuracy. The position corrections lc, Lc are calculated based on the latest position lr, Lr provided by the GPS receiver 14, the saved/interpolated dead reckoned position ls, Ls, and the GPS antenna moment arm (lever arm) corrections (discussed below) la, La based on the saved/interpolated attitude data corresponding to the GPS
data time.
The system uses the attitude data from the navigation system 10 for GPS antenna lever arm corrections. An antenna mounted on top of a vehicle such as a tractor or floater would be about 13 feet from the ground and will experience large attitude excursions as the vehicle swaths a field. As shown in Figure 3, the system takes this into account by using the attitude data to make GPS position corrections based on the current attitude of the vehicle and the known position of the GPS antenna relative to the vehicle. As a result, as the vehicle travels over terraces, ruts, bumps, etc., the relatively large swings of the GPS antenna will not effect the accuracy of the GPS position. Using similar techniques, the position calculated by the system can be transferred to any part of the vehicle, for example to the end of a sprayer boom.
Figure 4 shows a block diagram of the dead reckoning navigation function. The velocity sensed by the Doppler velocity sensor 30 is transformed from mount to body axes, then transformed from body to local level axes using the attitude (pitch and roll) and heading data from the attitude integration algorithm 42 shown in Figure 2. After the body to local level transform, the velocity is then transformed from local level to north referenced navigation axes.
Finally, the data is provided to the position integration function 52 which is reset according to the available position correction values lc, Lc coming from the position correction function shown in Figure 3.
Figure 5 shows a block diagram of the guidance function of the present invention. As shown in Figure 5, the position of the vehicle determined by the position integration (Figure 4) is supplied to a guidance algorithm 54 along with the vehicle's heading and the desired path. The guidance algorithm 54 uses this data to determine the cross track error and the heading error. From the cross track and heading errors, the system creates guidance commands. The,.
guidance commands are provided to an operator perceivable display 56 and/or an automatic steering mechanism 58 (see discussion below). The display 56 may take on any form. The display 56 could be display unit 18 (discussed above), a light bar (discussed below), or any other type of operator perceivable indicator. The automatic steering mechanism 58 could also take on any form. For example, the steering mechanism could be a hydraulic steering mechanism.
The navigation/guidance system of the present invention operates as follows. Before the host vehicle moves, the navigation system will'initialize itself. The attitude (pitch and roll) is initialized by the accelerometers 26.
The heading is initialized by the magnetic heading compass 28. The heading initialization is the most important initialization step. If the vehicle is, moving the magnetic heading compass 28 will not be used to initialize the heading. The system is initialized based on where the operator of the vehicle indicates the vehicle is located and/or by GPS data. In other words, the operator can manually enter in the initial location and/or the system can use the GPS location.
Once the host vehicle begins moving the system 10 uses the various sensors to sense the movement of the vehicle.
The attitude (pitch and roll) and heading of the host vehicle is sensed by the gyros 24. The speed of the vehicle is sensed by the Doppler radar 30. After sensing the attitude, heading, and speed, the system 10 calculates the velocity of the vehicle. The velocity of the vehicle is then integrated to determine the position of the vehicle. The system then uses a process to correct for errors in the system (see Figure 3). The speed, heading and dead reckoning position errors are corrected by periodic GPS fixes. The attitude pitch and roll errors are corrected by sensing the acceleration caused by the motion of the vehicle. This is done via the accelerometers 26 and the knowledge of the vehicle speed and rotation rate. The accelerometers 26 sense the specific force accelerations acting on the vehicle including gravity, the acceleration of the vehicle, and centrifugal force. The gravity force is a known value and can be subtracted out. The remaining accelerations are then integrated to get a velocity. Similarly, the velocity and rotation rate of the vehicle are known and can be subtracted out. The remaining values can be used to correct the attitude errors.
A vehicle using the navigation system l0 to help control a guidance system operates as follows and as described with Figure 5 above. The primary information used by the guidance system from the navigation system 10 is the position of the host vehicle. As shown in Figure 5, the guidance system receives a position signal from the navigation system 10 at a rate of 10 Hz. The guidance system also receives a vehicle heading signal from the navigation system 10 at a 10 Hz rate.
Of course, the position and heading data could be received at any other suitable rate, but 10 Hz is the preferred rate.
The desired path of the vehicle is provided to the guidance 2o system from the processor memory, user input, or any other source. The guidance system computes cross track and heading error. Cross track error is the distance the vehicle is off from the desired path. Heading error is defined as the angular difference between the vehicle velocity and the desired path. The goal of the guidance system is to drive the cross track error to zero by guiding the vehicle along a desired path. The guidance algorithm 54 described above calculates the cross track error and the heading error to create guidance commands. These guidance commands are the steering signal used by the operator or by an automatic steering mechanism to steer the vehicle along the desired path.
A vehicle equipped with the navigation system 10 of the present invention is capable of very accurately keeping track of where the vehicle is and where it has already been. This information can be used for any number of purposes or applications. The navigation system provides accurate, real time data sufficient to allow a guidance system to navigate along a curved path.
With the navigation system 10 of the present invention used on an agricultural vehicle such as a tractor or floater, the vehicle would~have many capabilities. An operator of the vehicle could manually steer through a path in the field and then use the system to guide the vehicle almost exactly parallel to the path on the next swath (see Figure 7, discussed below). This would maximize the efficiency of the vehicle and make the operator's tasks easier and more reliable. Similarly, an operator of the vehicle could manually navigate the vehicle around the edge of a field and command the vehicle to automatically cover the remainder of the field within the outside path. Since the system would have the previous paths in memory, the system would know what portions of the field remain and would be able to cover the remainder of the field. The operator could also manually navigate around waterways and allow the system to automatically navigate around the waterways when they are encountered. The system could also be used to help control the operation of machinery such as sprayers, disks, etc.
connected to the vehicles. For example, when a vehicle is turning around at the end of a field and is traveling over areas already sprayed, the sprayers could be automatically turned off until they reach a portion of the field not previously sprayed. Whatever the system is used for, the navigation information obtained could be saved and stored for subsequent operations in the same field. For example, once the system knows the locations of borders, obstacles, etc. in a field, that information can be used later to automatically navigate around a field without "relearning" that information. That would make the system even more efficient after the initial operation in a particular field.
Figure 6 shows a tractor 60 incorporating the present invention. A GPS antenna 22'is mounted to the top of the tractor 60. The Doppler sensor 30 is mounted on the front of the tractor 60. The remaining components of the system 10, are also mounted to the tractor 60. _ Figure 7 shows an aerial view of a field being worked by the tractor 60. The tractor is shown pulling a sprayer 62 through the field. As shown in Figure 7, the tractor 60 first sprayed the end rows 64. Next, the tractor was guided along a first swath 66A which followed the shape of the edge of the field. Dashed line 68A shows the path of the tractor 60 during the first swath 66A. The swath 66A is shaded to show that it was sprayed. At the end of the first swath 66A, the guidance system, knowing the location of the end rows 64 and knowing the location of the first swath 66A is able to cause the tractor 60 to turn around and follow the path 68B
to start the second swath 66B. Figure 7 shows the tractor 60 as it is making a fourth swath 66D following the path 68D.
Also note that the sprayer 62 can be automatically turned off at the end of each swath 66 as the sprayers pass over portions of the field already sprayed. As discussed above, the system 10 is capable of navigating~in a curved or uneven path.
An agricultural floater equipped with the present invention would have many capabilities not found in the prior art. First, the reliability of the operators hired to operate the floaters would be less important. The guidance system on the floater would enable the floater to automatically move through the field, for example with an automatic hydraulic steering system. Alternatively, the guidance system could assist the operator in moving through the field via a light bar or other display device. As a result, the entire field would be covered with the proper amount of chemicals giving the farmer higher yields and saving the chemical supplier money from less wasted chemicals. Second, the floaters could operate at night since the operator would not need to watch for the foam markers or other external indictors required by prior art systems. As a result, the chemical applier could use and maintain fewer floaters_to spray the same amount of land.
Other applications of the present invention can be seen as well. For example, when the navigation/guidance system is applied to any other vehicle, many of the same advantages are found. In addition, given a typical $90,000 tractor, $60,000 of that cost goes toward the creature comforts such as a cab, air conditioning, etc. With a fully automatic guidance system, the operator and hence the creature comforts are not needed and $60,000 could be cut from the price of the tractor. The navigation/guidance system could also be used to quickly and efficiently survey land. With the system installed on a vehicle, for example a 4-wheeler, a user could simply drive over a given piece of land while the system keeps a record of precisely where the vehicle has been and the elevation at each point. This data could be transmitted or downloaded to a computer to be interpreted and used.
Software such as CAD could then be used. to create three dimensional maps of the surveyed land. Lawn services could use the navigation/guidance system with lawn sprayers or mowers as described above. Excavating~machinery such as bulldozers could use the system to automatically excavate land. The navigation system is also capable of use on boats or ships. Vehicles traveling through water encounter similar problems as do vehicles traveling on the ground. For example, waves and strong winds as well as other forces can dramatically manipulate the attitude of the ship causing problems described above such as the GPS antenna lever arm errors. The navigation system could also be used on boats to survey the bottom of bodies of water. An additional sensor such as sonar could be used to sense the depth of the water at every location that the boat traveled over. This data could be used to determine where silt build-up exists around dams for example. The rail industry could use the navigation/guidance system to keep track of and control trains. The navigation system will continue to operate even while the trains go trough tunnels or under foliage, etc.
The railroads could fit more trains on a given track if they knew precisely where each train was. Also, the system is accurate enough to indicate which track a train is on, even where two tracks run parallel in close proximity. Regardless of how the present invention is used, the user will save time, labor, cost, etc.
The preferred embodiment of the navigation system 10 of the present invention may be configured as follows. A sensor package is contained within a single enclosure. The sensor package includes the rate gyros 24, the accelerometers 26 and the magnetic heading compass 28. The sensor package could act as a stand-alone inertial measurement unit with the capability of connecting to a vehicle and any other sensors desired. The Doppler radar position sensor 30 is attached to the vehicle and preferably pointed downward toward the ground at an angle of about 30°. A display head includes the display unit 18, the processor 12, the GPS receiver 14, a tactile device (e. g., a keypad or keyboard), the DGPS radio receiver and the required power supplies. Two antennas (one GPS and one DGPS) are attached to the vehicle and connected to the appropriate receiver. Finally, a light bar is installed on the vehicle in view of the operator and also connected to the display head. The light bar is comprised of a row of lights that indicate the magnitude and direction of the cross track error to the operator. In response to the light bar indication the operator could steer left or right in order to continue on a desired path. Optionally, the system 10 may provide guidance commands to an automatic steering mechanism.
The preferred embodiment of the present invention has been set forth in the drawings and specification, and although specific terms are employed, these are used in a generic or descriptive sense only and are not used for purposes of limitation. Changes in the form and proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit and scope of the invention as further defined in the following claims.
l8
VEHICLE
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to inertial navigation systems. More particularly, though not exclusively, the present invention relates to an inertial navigation/guidance system using a radio navigation receiver to correct the navigation errors.
PROBLEMS IN THE ART
Differential global positioning system (DGPS) based guidance systems for airborne application of agrochemicals has met with huge success and it follows that this technology could be used with ground rig applicators if certain technical problems can be overcome. The primary differences between air and ground application processes are associated with the operators view of the land and the operational dynamic environment.
During airborne applications, the pilot generally has a large part of the area involved to be sprayed in view and the GPS antenna (mounted on top of the canopy) follows a relatively straight line when in an application swath. This provides for the required cross track position stability to obtain a well controlled application process.
With ground rig applicators, such as tractors or floaters, the operator may have a limited view of the involved spray area and depending on the size/shape of the field and of the local ground cover it can be very difficult to determine where the previous swath coverage ends in order to proceed with the ensuing swath. A GPS antenna mounted on top of the ground vehicle (where it would be exposed to the GPS satellites) will experience large attitude excursions as the rig swaths the field. This results in GPS derived cross track position excursions relative to the vehicle ground track which would contaminate any attempt to parallel a defined field line. It can therefore be seen that there is a ~ SUBSTITUTE SHEET (RULE 2B) need for a better navigation/guidance system for use with a ground-based vehicle.
There is a need for a solution to various problems relating to ground rig applicators such as tractors and floaters. These ground rig applicators have several disadvantages. Since the application of agrochemicals is a seasonal process t3-4 months per year), the workers hired to operate the floaters are seasonal workers. As a result, the seasonal workers are often inexperienced or unreliable in the operation of the floaters. This increases the probability that the operator will skip areas of the field or apply double coverage to overlapping areas. These problems cost the seller of the chemicals and the farmer thousands of dollars. A typical floater will cost $100,000 and will apply $500,000 - $1 million dollars worth of chemicals per year.
It can therefore be seen that efficient operating of a floater is very important. Typical prior art floaters are guided through a field by following a trail of foam markers which are marked on the field on the previous swath. As a result, there is a lot of room for human error and the floaters cannot be operated at night. A need can therefore be seen which would allow the floaters to operate accurately day or night throughout the season. Such a solution would allow a chemical applier to operate half as many machines.
An accurate, real-time inexpensive navigation/guidance system would remedy these problems.
Various prior art navigation systems for ground-based vehicles have several disadvantages. Systems using Doppler radar will encounter errors with the radar. Similarly, gyros will encounter drift errors which will continue to increase unless the drift error is corrected. Gyros that are inexpensive enough to be feasible to use may have drift rates high enough to make them unusable. For example, a typical inexpensive gyro sensor may have a drift rate uncertainty as high as 3600° per hour which makes the gyro unusable for most applications. As a result, gyros have good short term SUBSTITUTE SHEET (RULE 26) characteristics but bad long term characteristics as the drift error becomes larger ~s t.ime goes on.
When navigat=ing using dead reckoning you need a very high fidelity heading measura:ment which ria:~ not been achieved adequately using low costs sensors.
Various prior ar; syst:ems navigating by GPS also have disadvantages. Prior art systems using GPS use GPS as the primary navigator. T:n.i.s intens.ifi_e:~ the problerns found. with GPS. A GPS position ca l.c.ulation has a lag time. As a result, the position solnztion provided by a GPS receiver_ tells a user where the vehicle was a moment ago not in real time. Another problem with GPS systt~rns are the errors resu Lting from the antenna lever arm problem. A GPS antenna typically is a certain dist<~nce away frc>m the c:~P.S receiver. Since the GPS
1S antenna is the collection point of the GPS signals received, the position solution wi.l.l. not ~accurat:ely describe the position of the GPS receiver or some other reference point.
If the geometrical di.:>tarvce between the GPS sveceiver or reference point and the GPS antenna is known, the position of the reference point ma:ry be calculated. However, as a ground based vehicle travels over uneven terrain such as terraces, slopes, ruts, bumps, E:et.e., the actual. position of the GPS
antenna cannot be determined resulting in erratic GPS position solutions.
2S Most prior art attempts to use a GPS navigation system attempted to deal withr problems by correcting GPS drift and lag time. However no prior art s=stem navigating by GPS has achieved the high accuracy and r_ea1 time soli_ztions required for applications requiring a high level of accuracy. The 3G prior art attempts ha~;e n.ot prcmicled an adeguate solution because GPS does not provide a continuous navigation solution.
A GPS system will upd~:<te its posit_.ion periodically, not in real time, and a lag time is still. involved. Another problem with a GPS system is the possibility of a signal dropout of the satellite signals. The accuracy of a GP;:~ system is also limited due i~o the er:r.c:~rs caused by the ionosphere. Another problem with GPS systems is that altitude data provided by a ~~ GPS receiver is not pre~,..ise.
Another problem ~~ait.h ~:~PS syst.erris is that a GPS system cannot accurately supply guidan::e data for_ a curved path.
This problem relates i-:o the lack t:i.rne involved w.i.th GPS. A GPS
system can only do linear interpolation of GPS position solutions whi.~~h is inadequate for navigating a curved path. A
GPS system also will root provide high quality heading information. Finally, the altitude calculated by a GPS
receiver is inaccurate and unusable for certain applications.
Publication WO 91.!09315 discloses an integrated vehicle positioning and navigation system, apparatus and method. It describes improving accuracy of position est:imat.ion by combining GPS, inertial and odometer data, and by predetermined weighting of .such data, outputting a position estimate. It discloses the use of expansive components and a complex system that tries to reduce the problems with the various components and r;hei_r acco.zracy.
Publication WO 95/:L~3432 is entii=led "Field Navigation System". It describes what it calls a dead z:eckoning navigation system, usi:vg data from a compass, GPS, and a radar gun as inputs to a posi.t~ion computer. Imprcved accuracy of estimated pos=ition is t:ai.tght by pre-Loading a map into the system so that a cross cheek of the estimated calculated position can be made to the pre-:Loaded map. "'his adds complexity and the burc:ler~ of having a pre-loaded map for the area the vehicle is in.
FEATURES OF ~'HE INVENTION
A general feature <at the present invention is the provision of an inert.~..al navigation/guidance system.
A further feature c~t the yresent inventi..on is the provision of an inertial navigat:ion/guidance system for use on a land-based vehicle.
A further featurE:~ of the present invention is the provision of an inertial navigau~ion/guidance system that senses the attitude ofthe vehic~lEa.
A further feature of the present invention is the provision of an inertial. navigat~ion/guidance system which uses a radio navigation rec:e:i per 'to <:orrect the d.ri.ft errors of the inertial system.
A further. feature o.f the present invention is the provision of an inertial nav:igat:icn/~~u.ie~ance system which uses inexpensive sensors to achieve :~ highly accurate result.
A further feature ofi the present :invention is the provision of an inerti.:~1 attitude determination system which is stand alone.
A furtherr feature of the present: invention is the provision of <~n inertial navigation/guidance system which uses gyro information to compute the attitude and heading of the vehicle and a pos:i.tion <:v~ange serusor to sense the speed of the vehicle.
A further_ feature of the present. invention is the provision of yin inerti<;~=L. navigati.on/guidance ~7ystem which uses accelerometers to measure the pitch and roll of the vehicle to refine the sensed attitude of the vehicle.
A further feature of the present invention is the provision of an inertial navigation/guidance system which includes software to control the functions of the system.
A further feature of the present invention is the provision of an inertial navigation/guidance system which uses the sensed attitude of the vehicle to determine the position of the radio navigation antenna in order to correct l0 the lever-arm error.
A further feature of the present invention is the provision of a system for use on a boat or ship.
A further feature of the present invention is the provision of a system which is part of a surveying system.
These as well as other features of the present invention will become apparent from the following specification and claims.
SVI~11RY O~' Tg8 INVENTION
The navigation and guidance system of the present invention provides accurate navigation data in real time using a dead reckoning navigator with periodic radio navigation fixes to correct for the drift of the inertial system. The system senses the speed, heading and attitude of the vehicle to determine a position of the vehicle. An external position reference provided by the radio navigation system is used to correct any error in the determined position.
The system is capable of correcting for the radio navigation antenna lever arm errors by using the attitude of the vehicle. The system may optionally be used on a ground or water based vehicle to provide navigation data and guidance commands to an automatic steering system. The system of the present invention may also be used on a agricultural vehicle to guide the vehicle through a field in a number of ways.
An aspect of the invention is to provide a method of navigating a non-airborne vehicle comprising the steps of: providing a position change sensor; sensing the speed of the vehicle using the position change sensor; providing an angular change sensor;
sensing the heading and attitude of the vehicle using the angular change sensor; providing an accelerometer; correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle; providing a radio navigation system;
storing positions of the vehicle each relative to a given point in time; determining an external position reference for a given point in time using data from the radio navigation system;
and correcting any error in determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time. The position change sensor may be comprised of a Doppler radar.
The angular change sensor may be comprised of gyro. The accelerometer may be comprised of a tilt sensor or an inclinometer. The radio navigation system may be comprised of a GPS system, a LORAN system or a GLONASS system. The method may further comprise the steps o~ providing a radio navigation antenna for use with the radio navigation system, said antenna having a known location relative to a reference point on the vehicle; determining the position of the radio navigation antenna based on the attitude of the vehicle and the known location of the antenna relative to the reference point; and determining the external position reference using the position of the radio navigation antenna. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or controlling location and travel of trains.
Another aspect of the invention is to provide a navigation system for a non-airborne vehicle comprising: a position change sensor for sensing the speed of the vehicle; a set of gyros for sensing the attitude and heading of the vehicle; a set of accelerometers for sensing the forces acting on the vehicle; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said vehicle at a known location relative to the vehicle;
and a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of: correcting the sensed attitude of the vehicle using the 6-a sensed forces acting on the vehicle; determining the velocity of the vehicle using the sensed speed, heading and attitude of the vehicle, determining a first position of the vehicle by integrating the determined velocity; storing said first position of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the vehicle and the known location of the antenna relative to the vehicle, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored first position of the vehicle for the same point in time. The position change sensor may be comprised of a Doppler radar. The set of gyros may be comprised of two gyro sensors or three gyro sensors. The radio navigation system may be a GPS system. The radio navigation system may further comprise a DGPS receiver. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or a guidance system port for providing data to a vehicle steering system. The data provided to a vehicle guidance system may relate to the vehicle position and heading. The data may also relate to a desired path.
The data may comprise a steering command signal. The data provided to a vehicle guidance system may include the cross track error and heading error.
Another aspect of the present invention is to provide a method of navigating a land-based agricultural vehicle through a field comprising the steps o~ sensing the speed of the vehicle; providing an inertial sensor system; sensing the head and attitude of the vehicle using the inertial sensor system; determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
storing position of the vehicle each relative to a given point in time;
providing a radio navigation system; determining an external position reference for a given point in time using data from the radio navigation system; producing true position data by correcting any error in the determined position of the vehicle using the external position reference and comparing it to the stored position of the vehicle for the same point in time; and using the true position data to accurately navigate through a field. The method may further comprise the steps of: providing a radio navigation system antenna coupled to the vehicle at a known location relative to the vehicle; determining the position of the antenna based on the attitude of the vehicle and the location of the antenna relative to the 6-b vehicle; and refining the determined external position reference based on the determined position of the antenna. The position change sensor may be comprised of a Doppler radar. The heading and attitude may be sensed using an angular change sensor.
The angular change sensor may be comprised of a plurality of gyros. The method may further comprise the steps o~ sensing the acceleration caused by the vehicle;
using the sensed acceleration caused by the vehicle to refine the determined position of the vehicle.
The radio navigation system may be comprised of a GPS. The method may further comprise the steps of determining the cross track error and heading error based on the true position data and a desired navigation path, or the step of creating a guidance command signal based on the determined cross track error and heading error, or the step of displaying information based on the guidance control signal, or the step of displaying information based on the true position data. Further, the land based agricultural vehicle may comprise a chemical sprayer. The navigating may comprise autonomous steering of the vehicle, surveying or mapping of an area, or controlling location and travel of trains.
Another aspect of the invention is to provide a method of compensating for a radio navigation system antenna lever arm for a non-airborne vehicle comprising the steps of providing a radio navigation system antenna having a known location relative to a reference point on the vehicle; providing an inertial system for sensing the angular changes of the vehicle; determining the attitude of the vehicle using data from the inertial system; and determining the position of the radio navigation system antenna based on the attitude of the vehicle and the known location of the radio navigation system antenna relative to the reference point.
Another aspect of the invention is to provide a navigation system for a tractor comprising: a position change sensor for sensing the speed of the tractor; a set of gyros for sensing the attitude and heading of the tractor; a set of angular change sensors for sensing the pitch and roll of the tractor; a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said tractor at a known location relative to the tractor; a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of: correcting the sensed attitude of the tractor using the sensed pitch and roll of the tractor; determined the velocity of the tractor using the sensed speed, 6-c heading and attitude of the tractor, determining a first position of the tractor by integrating the determined velocity, storing said first positions of the vehicle each relative to a given point in time; determining the position of the antenna based on the attitude of the tractor and the known location of the antenna relative to the tractor, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored position of the vehicle for the same point in time;
an output port connected to said processor for providing data to a tractor guidance system. The navigation system may further comprise a user perceivable display connected to said processor for displaying information. The display may be comprised of a light bar mounted on the tractor. The data may be comprised of the cross track error and the heading error. The tractor guidance system may be comprised of an automatic steering system. The data may be comprised of guidance commands for the automatic steering system. The navigating may comprise surveying or mapping of an area.
Another aspect of the invention is to provide a method of navigating a moving non-airborne vehicle comprising the steps of: (a) sensing the speed of a vehicle;
(b) sensing the heading and attitude of the vehicle from a known initialization position using an inertial sensor system having inherent drift that increases over time; (c) estimating in real time the position of the vehicle for discrete points in time based on steps (a) and (b); (d) storing the estimates correlated to the discrete points in time; and (e) correcting error between estimated position and actual position by periodically determining actual position correlated to discrete points in time of the vehicle, comparing a stored estimated position with an actual position for the radio navigation system, and adjusting estimated position if the comparison falls outside a predetermined range; thus periodically producing real-time true position data for navigation of the vehicle by correcting for the inherent drift of the inertial sensor system, by periodically, if needed, comparing past estimated and past actual position and adjusting, if, needed, therebetween.
The navigating may comprise autonomous steering of the vehicle. The navigating may comprise surveying or mapping of an area.
6-d 8RI8F DESCRIPTION OF TH$ DRAi~IINGS
Figure 1 shows a block diagram of the primary hardware elements of the navigation/guidance system of the present invention.
Figure 2 shows a functional block diagram of the attitude/heading portion of the present invention.
Figure 3 shows a functional block diagram of the position correction function of the present invention.
Figure 4 shows a functional block diagram of the dead l0 reckoning navigation function of the present invention.
Figure 5 shows a functional block diagram of the guidance function of the present invention.
Figure 6 shows a tractor using the system of the present invention.
Figure 7 is an aerial view of a field being worked by the tractor shown in Figure 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODII~NT
The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all alternatives, modifications, and equivalences which may be included within the spirit and scope of the invention. While the present invention is described as being used on a land based vehicle, it is intended that the invention cover other applications.
Also, the term land-based vehicle is meant to include vehicles on the ground or in the water, "land-based" is meant only to distinguish from airborne applications.
The navigation/guidance system of the present invention is a dead reckoning navigator which uses periodic GPS fixes to correct the drift of the inertial system. The system uses GPS antenna attitude compensation to improve the accuracy of the GPS fixes. The system primarily uses speed sensed by Doppler radar and attitude and heading sensed by a set of gyros. As discussed above, systems using a Doppler sensor and gyros have the problem of errors in the sensors. In addition, in order to use inexpensive sensors, very large errors are encountered. The system uses various processes to compensate for the erro-rs. The heading sensed by the gyros is aided by a magnetic heading compass and a GPS receiver.
The speed sensed by the Doppler radar is also aided by the GPS receiver. The system also uses accelerometers to improve the accuracy of the system. A set of horizontal accelerometers measure the roll and pitch of the vehicle.
This is used to provide the attitude integration algorithm (discussed below) with the vehicle horizontal rotations to more accurately calculate the attitude and heading.
Figure 1 shows the primary hardware elements of the inertial navigation/guidance system 10 of the present invention. The system 10 is comprised of a personal computer (PC) 12 which includes a CPU, memory and input/output electronics. Although the embodiment shown in the drawings shows a personal computer, the invention.could use a processor circuit that includes a CPU, memory, and input/output electronics on a single processor card. A GPS
receiver 14 plugs directly into an open°PC expansion slot.
20~ Any GPS receiver suitable for use with the present invention may be used, however the preferred GPS receiver is the NovAtel GP5 receiver card #9518. Alternatively, the system l0 could simply have a connector that would receive GPS data from any existing GPS receiver. Any other type of radio navigation system or combination of systems could be substituted for the GPS system such as LORAN, GLONASS, etc.
A keyboard or keypad 16 is connected to the PC 12 and is used as a user interface to input data or control the system 10.
A display unit 18 is also connected to the PC 12. The display unit 18 is used to display various information to a user. The display unit 18 could take on many forms, but is preferably comprised of a CRT display. The display unit could even be comprised of a display screen that shows the operator a graphic of a field or portion of the field and could indicate where the vehicle has been and where it is going. All'sensor input data to the PC 12 will be digital serial. If any of the selected sensors provide only analog outputs, A/D converters will be used where required to obtain the appropriate input data formats. Also shown in Figure 1 is a block diagram of the power supply circuit used by the present invention. The power supply circuit includes a 12 volt battery 32, a voltage converter 34 and a power supply 36. The power supply circuit provides the system 10 with 110 volts AC and a regulated DC voltage.
A portable DGPS receiver 20 is also connected to the PC
12. The DGPS radio receiver 20 receives DGPS data for use by the PC to overcome the effects of Selective Availability (SA) as well as other imperfections in the time-coded signals broadcast by the NAVSTAR satellites. The use of DGPS
provides a more accurate location solution than GPS alone.
The DGPS radio receiver 20 may be any type of DGPS receiver suitable for use with the present invention but is preferably the Smartbase model number 10, manufactured by Premier GPS
Inc. Also note that the present invention would work without using DGPS, although the accuracy may be less. One alternative to the preferred embodimentyis to use a receiver that uses a combination of GPS and GLONASS signals to produce a more accurate radio navigation system.
A GPS antenna 22 is connected to the GPS receiver 14 to provide the GPS receiver 14 with GPS signals from the NAVSTAR
satellites. The GPS antenna 22 acts as the collection point for GPS signals received by the GPS receiver 14. The GPS
antenna 22 is mounted to the host vehicle at a known location such that the location of the antenna 22 is always known relative to the GPS receiver 14 or some other reference point.
As shown in Figure 1, a number of sensors are also connected to the PC 12. Three rate gyros 24, three accelerometers 26, and a magnetic heading compass 28 axe connected to the PC 12 to provide the system with various data. Preferably, the.gyros 24, accelerometers 26 and the magnetic heading compass 28 are assembled together in a single unit. A position change sensor 30, preferably comprised of a Doppler radar is also connected to the PC 12 to provide the system with speed data. Although the preferred embodiment uses three each of the gyros 24 and accelerometers 26, more or less could be used. The choice of using two or three accelerometers depends on such factors as the level of accuracy desired, the application of the system, and the sophistication of the Kalman filter, etc. The gyros 24 act as angular change sensors, so therefore, any device with the same function could be substituted for the gyros 24.
The preferred gyros are the model ENV-05H-02 manufactured by Murata Erie Co., Ltd. Similarly, the accelerometers 26 could be substituted by an equivalent device such an inclinometer, tilt sensors, etc. The preferred accelerometer is the model 02753-O1 manufactured by Lucas Control System Products. The magnetic heading compass could also be substituted by any other heading sensor, for example, a fluxgate compass. The preferred magnetic heading compass is the model C100 manufactured by KVH Industries, Inc. Also note that the magnetic heading compass 28 is optional. Depending on the sophistication of the Kalman filter and other factors, the magnetic heading compass 28 may not be needed by the system.
The Doppler radar 30 functions as a position change sensor, so therefore any equivalent device could be substituted for the Doppler radar such as an odometer or any other device used to derive the vehicle speed. The preferred Doppler radar is the model Radar II manufactured by Dickey-John.
Figure 2 shows a functional block diagram of the attitude/heading portion of the invention. The navigation/guidance system 10 uses software which performs the functions described and outlined in the figures. As described below, the attitude integration algorithm 42 uses the angular rates from the gyros 24, horizontal accelerations from the horizontal accelerometers 26, and heading and attitude error estimates from the other sensors to calculate a value for the vehicle s attitude (pitch and roll) and heading. The attitude and heading are primarily sensed by the gyros 24. The various sensors are used together as shown in the figures to obtain a more accurate value for attitude (pitch and roll) and heading. The data from the gyros 24 ~.s applied the gyro compensator function 40 which applies constant values such as a scale factor, misalignment and fixed bias to the data and also applies changing values such as an estimated dynamic bias to the data. The data is then provided to the attitude integration algorithm 42 to calculate the attitude and heading. The horizontal accelerometers 26 provide data to the accelerometer compensation function 46 which applies constant values such as scale factor, bias, and misalignments to the data. The compensated data from the accelerometers 26 is then provided to a direction cosine matrix (shown in Figure 2 as the body to navigation frame transformation function 48) and a platform leveling/damping function 50. The yaw attitude is slaved to the magnetic heading reference supplied by the magnetic heading compass 28. This, along with data from the GPS position are used by a blending filter 44 to provide a heading error estimate to the attitude integration algorithm 42. A pitch and roll error estimate is also provided to the attitude integration algorithm 42. The pitch and roll error estimate is derived from data from the Doppler radar 30, the horizontal accelerometers 26, and the gyros 24.
The attitude, heading and corresponding time are saved in a data table for interpolation to the GPS data time. This interpolated data is required to provide position corrections to the GPS position fix (see discussion of Figure 3 below) for use in the dead reckoning navigation function shown in Figure 4 (discussed below).
Figure 3 is a block diagram of the position correction function. As described above, the GPS receiver 14 is connected to the GPS antenna 22 to receive GPS data signals from the NAVSTAR satellites. The GPS receiver 14 also receives DGPS data from the DGPS radio receiver 20 to improve the GPS accuracy. The position corrections lc, Lc are calculated based on the latest position lr, Lr provided by the GPS receiver 14, the saved/interpolated dead reckoned position ls, Ls, and the GPS antenna moment arm (lever arm) corrections (discussed below) la, La based on the saved/interpolated attitude data corresponding to the GPS
data time.
The system uses the attitude data from the navigation system 10 for GPS antenna lever arm corrections. An antenna mounted on top of a vehicle such as a tractor or floater would be about 13 feet from the ground and will experience large attitude excursions as the vehicle swaths a field. As shown in Figure 3, the system takes this into account by using the attitude data to make GPS position corrections based on the current attitude of the vehicle and the known position of the GPS antenna relative to the vehicle. As a result, as the vehicle travels over terraces, ruts, bumps, etc., the relatively large swings of the GPS antenna will not effect the accuracy of the GPS position. Using similar techniques, the position calculated by the system can be transferred to any part of the vehicle, for example to the end of a sprayer boom.
Figure 4 shows a block diagram of the dead reckoning navigation function. The velocity sensed by the Doppler velocity sensor 30 is transformed from mount to body axes, then transformed from body to local level axes using the attitude (pitch and roll) and heading data from the attitude integration algorithm 42 shown in Figure 2. After the body to local level transform, the velocity is then transformed from local level to north referenced navigation axes.
Finally, the data is provided to the position integration function 52 which is reset according to the available position correction values lc, Lc coming from the position correction function shown in Figure 3.
Figure 5 shows a block diagram of the guidance function of the present invention. As shown in Figure 5, the position of the vehicle determined by the position integration (Figure 4) is supplied to a guidance algorithm 54 along with the vehicle's heading and the desired path. The guidance algorithm 54 uses this data to determine the cross track error and the heading error. From the cross track and heading errors, the system creates guidance commands. The,.
guidance commands are provided to an operator perceivable display 56 and/or an automatic steering mechanism 58 (see discussion below). The display 56 may take on any form. The display 56 could be display unit 18 (discussed above), a light bar (discussed below), or any other type of operator perceivable indicator. The automatic steering mechanism 58 could also take on any form. For example, the steering mechanism could be a hydraulic steering mechanism.
The navigation/guidance system of the present invention operates as follows. Before the host vehicle moves, the navigation system will'initialize itself. The attitude (pitch and roll) is initialized by the accelerometers 26.
The heading is initialized by the magnetic heading compass 28. The heading initialization is the most important initialization step. If the vehicle is, moving the magnetic heading compass 28 will not be used to initialize the heading. The system is initialized based on where the operator of the vehicle indicates the vehicle is located and/or by GPS data. In other words, the operator can manually enter in the initial location and/or the system can use the GPS location.
Once the host vehicle begins moving the system 10 uses the various sensors to sense the movement of the vehicle.
The attitude (pitch and roll) and heading of the host vehicle is sensed by the gyros 24. The speed of the vehicle is sensed by the Doppler radar 30. After sensing the attitude, heading, and speed, the system 10 calculates the velocity of the vehicle. The velocity of the vehicle is then integrated to determine the position of the vehicle. The system then uses a process to correct for errors in the system (see Figure 3). The speed, heading and dead reckoning position errors are corrected by periodic GPS fixes. The attitude pitch and roll errors are corrected by sensing the acceleration caused by the motion of the vehicle. This is done via the accelerometers 26 and the knowledge of the vehicle speed and rotation rate. The accelerometers 26 sense the specific force accelerations acting on the vehicle including gravity, the acceleration of the vehicle, and centrifugal force. The gravity force is a known value and can be subtracted out. The remaining accelerations are then integrated to get a velocity. Similarly, the velocity and rotation rate of the vehicle are known and can be subtracted out. The remaining values can be used to correct the attitude errors.
A vehicle using the navigation system l0 to help control a guidance system operates as follows and as described with Figure 5 above. The primary information used by the guidance system from the navigation system 10 is the position of the host vehicle. As shown in Figure 5, the guidance system receives a position signal from the navigation system 10 at a rate of 10 Hz. The guidance system also receives a vehicle heading signal from the navigation system 10 at a 10 Hz rate.
Of course, the position and heading data could be received at any other suitable rate, but 10 Hz is the preferred rate.
The desired path of the vehicle is provided to the guidance 2o system from the processor memory, user input, or any other source. The guidance system computes cross track and heading error. Cross track error is the distance the vehicle is off from the desired path. Heading error is defined as the angular difference between the vehicle velocity and the desired path. The goal of the guidance system is to drive the cross track error to zero by guiding the vehicle along a desired path. The guidance algorithm 54 described above calculates the cross track error and the heading error to create guidance commands. These guidance commands are the steering signal used by the operator or by an automatic steering mechanism to steer the vehicle along the desired path.
A vehicle equipped with the navigation system 10 of the present invention is capable of very accurately keeping track of where the vehicle is and where it has already been. This information can be used for any number of purposes or applications. The navigation system provides accurate, real time data sufficient to allow a guidance system to navigate along a curved path.
With the navigation system 10 of the present invention used on an agricultural vehicle such as a tractor or floater, the vehicle would~have many capabilities. An operator of the vehicle could manually steer through a path in the field and then use the system to guide the vehicle almost exactly parallel to the path on the next swath (see Figure 7, discussed below). This would maximize the efficiency of the vehicle and make the operator's tasks easier and more reliable. Similarly, an operator of the vehicle could manually navigate the vehicle around the edge of a field and command the vehicle to automatically cover the remainder of the field within the outside path. Since the system would have the previous paths in memory, the system would know what portions of the field remain and would be able to cover the remainder of the field. The operator could also manually navigate around waterways and allow the system to automatically navigate around the waterways when they are encountered. The system could also be used to help control the operation of machinery such as sprayers, disks, etc.
connected to the vehicles. For example, when a vehicle is turning around at the end of a field and is traveling over areas already sprayed, the sprayers could be automatically turned off until they reach a portion of the field not previously sprayed. Whatever the system is used for, the navigation information obtained could be saved and stored for subsequent operations in the same field. For example, once the system knows the locations of borders, obstacles, etc. in a field, that information can be used later to automatically navigate around a field without "relearning" that information. That would make the system even more efficient after the initial operation in a particular field.
Figure 6 shows a tractor 60 incorporating the present invention. A GPS antenna 22'is mounted to the top of the tractor 60. The Doppler sensor 30 is mounted on the front of the tractor 60. The remaining components of the system 10, are also mounted to the tractor 60. _ Figure 7 shows an aerial view of a field being worked by the tractor 60. The tractor is shown pulling a sprayer 62 through the field. As shown in Figure 7, the tractor 60 first sprayed the end rows 64. Next, the tractor was guided along a first swath 66A which followed the shape of the edge of the field. Dashed line 68A shows the path of the tractor 60 during the first swath 66A. The swath 66A is shaded to show that it was sprayed. At the end of the first swath 66A, the guidance system, knowing the location of the end rows 64 and knowing the location of the first swath 66A is able to cause the tractor 60 to turn around and follow the path 68B
to start the second swath 66B. Figure 7 shows the tractor 60 as it is making a fourth swath 66D following the path 68D.
Also note that the sprayer 62 can be automatically turned off at the end of each swath 66 as the sprayers pass over portions of the field already sprayed. As discussed above, the system 10 is capable of navigating~in a curved or uneven path.
An agricultural floater equipped with the present invention would have many capabilities not found in the prior art. First, the reliability of the operators hired to operate the floaters would be less important. The guidance system on the floater would enable the floater to automatically move through the field, for example with an automatic hydraulic steering system. Alternatively, the guidance system could assist the operator in moving through the field via a light bar or other display device. As a result, the entire field would be covered with the proper amount of chemicals giving the farmer higher yields and saving the chemical supplier money from less wasted chemicals. Second, the floaters could operate at night since the operator would not need to watch for the foam markers or other external indictors required by prior art systems. As a result, the chemical applier could use and maintain fewer floaters_to spray the same amount of land.
Other applications of the present invention can be seen as well. For example, when the navigation/guidance system is applied to any other vehicle, many of the same advantages are found. In addition, given a typical $90,000 tractor, $60,000 of that cost goes toward the creature comforts such as a cab, air conditioning, etc. With a fully automatic guidance system, the operator and hence the creature comforts are not needed and $60,000 could be cut from the price of the tractor. The navigation/guidance system could also be used to quickly and efficiently survey land. With the system installed on a vehicle, for example a 4-wheeler, a user could simply drive over a given piece of land while the system keeps a record of precisely where the vehicle has been and the elevation at each point. This data could be transmitted or downloaded to a computer to be interpreted and used.
Software such as CAD could then be used. to create three dimensional maps of the surveyed land. Lawn services could use the navigation/guidance system with lawn sprayers or mowers as described above. Excavating~machinery such as bulldozers could use the system to automatically excavate land. The navigation system is also capable of use on boats or ships. Vehicles traveling through water encounter similar problems as do vehicles traveling on the ground. For example, waves and strong winds as well as other forces can dramatically manipulate the attitude of the ship causing problems described above such as the GPS antenna lever arm errors. The navigation system could also be used on boats to survey the bottom of bodies of water. An additional sensor such as sonar could be used to sense the depth of the water at every location that the boat traveled over. This data could be used to determine where silt build-up exists around dams for example. The rail industry could use the navigation/guidance system to keep track of and control trains. The navigation system will continue to operate even while the trains go trough tunnels or under foliage, etc.
The railroads could fit more trains on a given track if they knew precisely where each train was. Also, the system is accurate enough to indicate which track a train is on, even where two tracks run parallel in close proximity. Regardless of how the present invention is used, the user will save time, labor, cost, etc.
The preferred embodiment of the navigation system 10 of the present invention may be configured as follows. A sensor package is contained within a single enclosure. The sensor package includes the rate gyros 24, the accelerometers 26 and the magnetic heading compass 28. The sensor package could act as a stand-alone inertial measurement unit with the capability of connecting to a vehicle and any other sensors desired. The Doppler radar position sensor 30 is attached to the vehicle and preferably pointed downward toward the ground at an angle of about 30°. A display head includes the display unit 18, the processor 12, the GPS receiver 14, a tactile device (e. g., a keypad or keyboard), the DGPS radio receiver and the required power supplies. Two antennas (one GPS and one DGPS) are attached to the vehicle and connected to the appropriate receiver. Finally, a light bar is installed on the vehicle in view of the operator and also connected to the display head. The light bar is comprised of a row of lights that indicate the magnitude and direction of the cross track error to the operator. In response to the light bar indication the operator could steer left or right in order to continue on a desired path. Optionally, the system 10 may provide guidance commands to an automatic steering mechanism.
The preferred embodiment of the present invention has been set forth in the drawings and specification, and although specific terms are employed, these are used in a generic or descriptive sense only and are not used for purposes of limitation. Changes in the form and proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit and scope of the invention as further defined in the following claims.
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Claims (51)
1. A method of navigating a non-airborne vehicle comprising the steps of:
providing a position change sensor;
sensing the speed of the vehicle using the position change sensor;
providing an angular change sensor;
sensing the heading and attitude of the vehicle using the angular change sensor;
providing an accelerometer;
correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor;
determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
providing a radio navigation system;
storing positions of the vehicle each relative to a given point in time;
determining an external position reference for a given point in time using data from the radio navigation system; and correcting any error in the determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time.
providing a position change sensor;
sensing the speed of the vehicle using the position change sensor;
providing an angular change sensor;
sensing the heading and attitude of the vehicle using the angular change sensor;
providing an accelerometer;
correcting the sensed attitude of the vehicle using data from the accelerometer, position change sensor and angular change sensor;
determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
providing a radio navigation system;
storing positions of the vehicle each relative to a given point in time;
determining an external position reference for a given point in time using data from the radio navigation system; and correcting any error in the determined position of the vehicle using the determined external position reference and comparing it to the stored position of the vehicle for the same point in time.
2. The method of claim 1 wherein said position change sensor is comprised of a Doppler radar.
3. The method of claim 1 wherein said angular change sensor is comprised of a gyro.
4. The method of claim 1 wherein said accelerometer is comprised of a tilt sensor.
5. The method of claim 1 wherein said accelerometer is comprised of a inclinometer.
6. The method of claim 1 wherein said radio navigation system is comprised of a GPS system.
7. The method of claim 1 wherein said radio navigation system is comprised of a LORAN system.
8. The method of claim 1 wherein said radio navigation system is comprised of a GLONASS system.
9. The method of claim 1 further comprising the steps of:
providing a radio navigation antenna for use with the radio navigation system, said antenna having a known location relative to a reference point on the vehicle;
determining the position of the radio navigation antenna based on the attitude of the vehicle and the known location of the antenna relative to the reference point;
and determining the external position reference using data from the radio navigation system and using the determined position of the radio navigation antenna.
providing a radio navigation antenna for use with the radio navigation system, said antenna having a known location relative to a reference point on the vehicle;
determining the position of the radio navigation antenna based on the attitude of the vehicle and the known location of the antenna relative to the reference point;
and determining the external position reference using data from the radio navigation system and using the determined position of the radio navigation antenna.
10. The method of claim 1 wherein the navigating comprises autonomous steering of the vehicle.
11. The method of claim 1 wherein the navigating comprises surveying or mapping of an area.
12. The method of claim 1 wherein the navigating comprises controlling location and travel of trains.
13. A navigation system for a non-airborne vehicle comprising:
a position change sensor for sensing the speed of the vehicle;
a set of gyros for sensing the attitude and heading of the vehicle;
a set of accelerometers for sensing the forces acting on the vehicle;
a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said vehicle at a known location relative to the vehicle; and a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of:
correcting the sensed attitude of the vehicle using the sensed forces acting on the vehicle;
determining the velocity of the vehicle using the sensed speed, heading and attitude of the vehicle, determining a first position of the vehicle by integrating the determined velocity, storing said first position of the vehicle each relative to a given point in time;
determining the position of the antenna based on the attitude of the vehicle and the known location of the antenna relative to the vehicle, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored first position of the vehicle for the same point in time.
a position change sensor for sensing the speed of the vehicle;
a set of gyros for sensing the attitude and heading of the vehicle;
a set of accelerometers for sensing the forces acting on the vehicle;
a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said vehicle at a known location relative to the vehicle; and a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of:
correcting the sensed attitude of the vehicle using the sensed forces acting on the vehicle;
determining the velocity of the vehicle using the sensed speed, heading and attitude of the vehicle, determining a first position of the vehicle by integrating the determined velocity, storing said first position of the vehicle each relative to a given point in time;
determining the position of the antenna based on the attitude of the vehicle and the known location of the antenna relative to the vehicle, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored first position of the vehicle for the same point in time.
14. The navigation system of claim 13 wherein said position change sensor is comprised of a Doppler radar.
15. The navigation system of claim 13 wherein said set of gyros is comprised of two gyro sensors.
16. The navigation system of claim 13 wherein said set of gyros is comprised of three gyro sensors.
17. The navigation system of claim 13 wherein said radio navigation system is a GPS system.
18. The method of claim 17 wherein said radio navigation system further comprises a DGPS receiver.
19. The system of claim 13 wherein the navigating comprises autonomous steering of the vehicle.
20. The system of claim 13 wherein the navigating comprises surveying or mapping of an area.
21. The navigation system of claim 13 further comprising a guidance system port for providing data to a vehicle steering system.
22. The navigation system of claim 21 wherein said data provided to a vehicle guidance system relates to the vehicle position and heading.
23. The navigation system of claim 22 wherein said data also relates to a desired path.
24. The navigation system of claim 22 wherein said data comprises a steering command signal.
25. The navigation system of claim 21 wherein said data provided to a vehicle guidance system includes the cross track error and heading error.
26. A method of navigating a land-based agricultural vehicle through a field comprising the steps of:
sensing the speed of the vehicle;
providing an inertial sensor system;
sensing the heading and attitude of the vehicle using the inertial sensor system;
determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
storing positions of the vehicle each relative to a given point in time;
providing a radio navigation system;
determining an external position reference for a given point in time using data from the radio navigation system;
producing true position data by correcting any error in the determined position of the vehicle using the external position reference and comparing it to the stored position of the vehicle for the same point in time; and using the true position data to accurately navigate through a field.
sensing the speed of the vehicle;
providing an inertial sensor system;
sensing the heading and attitude of the vehicle using the inertial sensor system;
determining the position of the vehicle based on a known previous position and the sensed speed, heading, and attitude of the vehicle;
storing positions of the vehicle each relative to a given point in time;
providing a radio navigation system;
determining an external position reference for a given point in time using data from the radio navigation system;
producing true position data by correcting any error in the determined position of the vehicle using the external position reference and comparing it to the stored position of the vehicle for the same point in time; and using the true position data to accurately navigate through a field.
27. The method of claim 26 further comprising the steps of:
providing a radio navigation system antenna coupled to the vehicle at a known location relative to the vehicle;
determining the position of the antenna based on the attitude of the vehicle and the location of the antenna relative to the vehicle; and refining the determined external position reference based on the determined position of the antenna.
providing a radio navigation system antenna coupled to the vehicle at a known location relative to the vehicle;
determining the position of the antenna based on the attitude of the vehicle and the location of the antenna relative to the vehicle; and refining the determined external position reference based on the determined position of the antenna.
28. The method of claim 26 wherein said position change sensor is comprised of a Doppler radar.
29. The method of claim 26 wherein said heading and attitude are sensed using an angular change sensor.
30. The method of claim 29 wherein said angular change sensor is comprised of a plurality of gyros.
31. The method of claim 26 further comprising the steps of:
sensing the acceleration caused by the vehicle;
using the sensed acceleration caused by the vehicle to refine the determined position of the vehicle.
sensing the acceleration caused by the vehicle;
using the sensed acceleration caused by the vehicle to refine the determined position of the vehicle.
32. The method of claim 26 wherein said radio navigation system is comprised of a GPS.
33. The method of claim 26 further comprising the steps of determining the cross track error and heading error based on the true position data and a desired navigation path.
34. The method of claim 33 further comprising the step of creating a guidance command signal based on the determined cross track error and heading error.
35. The method of claim 34 further comprising the step of displaying information based on the guidance control signal.
36. The method of claim 26 further comprising the step of displaying information based on the true position data.
37. The method of claim 26 wherein said land based agricultural vehicle is comprised of a chemical sprayer.
38. The method of claim 26 wherein the navigating comprises autonomous steering of the vehicle.
39. The method of claim 26 wherein the navigating comprises surveying or mapping of an area.
40. The method of claim 26 wherein the navigating comprises controlling location and travel of trains.
41. A method of compensating for a radio navigation system antenna lever arm for a non-airborne vehicle comprising the steps of:
providing a radio navigation system antenna having a known location relative to a reference point on the vehicle;
providing an inertial system for sensing the angular changes of the vehicle;
determining the attitude of the vehicle using data from the inertial system;
and determining the position of the radio navigation system antenna based on the attitude of the vehicle and the known location of the radio navigation system antenna relative to the reference point.
providing a radio navigation system antenna having a known location relative to a reference point on the vehicle;
providing an inertial system for sensing the angular changes of the vehicle;
determining the attitude of the vehicle using data from the inertial system;
and determining the position of the radio navigation system antenna based on the attitude of the vehicle and the known location of the radio navigation system antenna relative to the reference point.
42. A navigation system for a tractor comprising:
a position change sensor for sensing the speed of the tractor;
a set of gyros for sensing the attitude and heading of the tractor, a set of angular change sensors for sensing the pitch and roll of the tractor;
a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said tractor at a known location relative to the tractor;
a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of:
correcting the sensed attitude of the tractor using the sensed pitch and roll of the tractor;
determining the velocity of the tractor using the sensed speed, heading and attitude of the tractor, determining a first position of the tractor by integrating the determined velocity, storing said first positions of the vehicle each relative to a given point in time;
determining the position of the antenna based on the attitude of the tractor and the known location of the antenna relative to the tractor, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored position of the vehicle for the same point in time;
an output port connected to said processor for providing data to a tractor guidance system.
a position change sensor for sensing the speed of the tractor;
a set of gyros for sensing the attitude and heading of the tractor, a set of angular change sensors for sensing the pitch and roll of the tractor;
a radio navigation system for sensing an external position reference for a given point in time, said radio navigation system including an antenna coupled to said tractor at a known location relative to the tractor;
a processor connected to each of said sensors and radio navigation system, said processor performing the processing steps of:
correcting the sensed attitude of the tractor using the sensed pitch and roll of the tractor;
determining the velocity of the tractor using the sensed speed, heading and attitude of the tractor, determining a first position of the tractor by integrating the determined velocity, storing said first positions of the vehicle each relative to a given point in time;
determining the position of the antenna based on the attitude of the tractor and the known location of the antenna relative to the tractor, correcting the external position reference based on the determined position of the antenna, and correcting the determined first position using the corrected external position reference by comparing it to the stored position of the vehicle for the same point in time;
an output port connected to said processor for providing data to a tractor guidance system.
43. The navigation system of claim 42 further comprising a user perceivable display connected to said processor for displaying information.
44. The navigation system of claim 43 wherein said display is comprised of a light bar mounted on the tractor.
45. The navigation system of claim 42 wherein said data is comprised of the cross track error and the heading error.
46. The navigation system of claim 42 wherein said tractor guidance system is comprised of an automatic steering system.
47. The navigation system of claim 46 wherein said data is comprised of guidance commands for the automatic steering system.
48. The method of claim 42 wherein the navigating comprises surveying or mapping of an area.
49. A method of navigating a moving non-airborne vehicle comprising the steps of:
(a) sensing the speed of a vehicle;
(b) sensing the heading and attitude of the vehicle from a known initialization position using an inertial sensor system having inherent drift that increases over time;
(c) estimating in real time the position of the vehicle for discrete points in time based on steps (a) and (b);
(d) storing the estimates correlated to the discrete points in time;
(e) correcting error between estimated position and actual position by periodically determining actual position correlated to discrete points in time of the vehicle, comparing a stored estimated position with an actual position for the radio navigation system, and adjusting estimated position if the comparison falls outside a predetermined range;
thus periodically producing real-time true position data for navigation of the vehicle by correcting for the inherent drift of the inertial sensor system, by periodically, if needed, comparing past estimated and past actual position and adjusting, if, needed, therebetween.
(a) sensing the speed of a vehicle;
(b) sensing the heading and attitude of the vehicle from a known initialization position using an inertial sensor system having inherent drift that increases over time;
(c) estimating in real time the position of the vehicle for discrete points in time based on steps (a) and (b);
(d) storing the estimates correlated to the discrete points in time;
(e) correcting error between estimated position and actual position by periodically determining actual position correlated to discrete points in time of the vehicle, comparing a stored estimated position with an actual position for the radio navigation system, and adjusting estimated position if the comparison falls outside a predetermined range;
thus periodically producing real-time true position data for navigation of the vehicle by correcting for the inherent drift of the inertial sensor system, by periodically, if needed, comparing past estimated and past actual position and adjusting, if, needed, therebetween.
50. The method of claim 49 wherein the navigating comprises autonomous steering of the vehicle.
51. The method of claim 49 wherein the navigating comprises surveying or mapping of an area.
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US08/596,957 US5928309A (en) | 1996-02-05 | 1996-02-05 | Navigation/guidance system for a land-based vehicle |
US08/596,957 | 1996-02-05 | ||
PCT/US1997/002445 WO1998036288A1 (en) | 1997-02-14 | 1997-02-14 | A navigation/guidance system for a land-based vehicle |
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CA2279877A1 CA2279877A1 (en) | 1998-08-20 |
CA2279877C true CA2279877C (en) | 2005-09-06 |
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CA002279877A Expired - Fee Related CA2279877C (en) | 1996-02-05 | 1997-02-14 | A navigation/guidance system for a land-based vehicle |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021233388A1 (en) * | 2020-05-21 | 2021-11-25 | 深圳市海柔创新科技有限公司 | Navigation method and navigation apparatus |
Families Citing this family (180)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6070673A (en) * | 1996-11-22 | 2000-06-06 | Case Corporation | Location based tractor control |
US5986547A (en) | 1997-03-03 | 1999-11-16 | Korver; Kelvin | Apparatus and method for improving the safety of railroad systems |
US5987383C1 (en) * | 1997-04-28 | 2006-06-13 | Trimble Navigation Ltd | Form line following guidance system |
DE19726917A1 (en) | 1997-06-25 | 1999-01-07 | Claas Selbstfahr Erntemasch | Device on agricultural machinery for contactless scanning of contours extending over the ground |
SE509209C2 (en) * | 1997-11-28 | 1998-12-14 | Spectra Precision Ab | Device and method for determining the position of the machining part |
US6141613A (en) * | 1998-03-18 | 2000-10-31 | Caterpillar Inc. | Apparatus and method for controlling the steering of a tracked machine |
IL124413A (en) * | 1998-05-11 | 2001-05-20 | Friendly Robotics Ltd | System and method for area coverage with an autonomous robot |
US6199000B1 (en) * | 1998-07-15 | 2001-03-06 | Trimble Navigation Limited | Methods and apparatus for precision agriculture operations utilizing real time kinematic global positioning system systems |
AUPP679598A0 (en) * | 1998-10-27 | 1998-11-19 | Agsystems Pty Ltd | A vehicle navigation apparatus |
US6205400B1 (en) * | 1998-11-27 | 2001-03-20 | Ching-Fang Lin | Vehicle positioning and data integrating method and system thereof |
US6166698A (en) * | 1999-02-16 | 2000-12-26 | Gentex Corporation | Rearview mirror with integrated microwave receiver |
US7275607B2 (en) | 1999-06-04 | 2007-10-02 | Deka Products Limited Partnership | Control of a personal transporter based on user position |
US6236924B1 (en) * | 1999-06-21 | 2001-05-22 | Caterpillar Inc. | System and method for planning the operations of an agricultural machine in a field |
AUPQ181699A0 (en) * | 1999-07-23 | 1999-08-19 | Cmte Development Limited | A system for relative vehicle navigation |
ATE345487T1 (en) | 1999-09-16 | 2006-12-15 | Sirf Tech Inc | NAVIGATION SYSTEM AND METHOD FOR TRACKING THE POSITION OF AN OBJECT |
DE19945120C2 (en) | 1999-09-21 | 2001-12-06 | Mannesmann Vdo Ag | Method of navigating a vehicle |
DE19945121C2 (en) * | 1999-09-21 | 2001-12-13 | Mannesmann Vdo Ag | Method of navigating a vehicle |
US6282496B1 (en) * | 1999-10-29 | 2001-08-28 | Visteon Technologies, Llc | Method and apparatus for inertial guidance for an automobile navigation system |
DE19958761A1 (en) * | 1999-12-08 | 2001-06-28 | Egon Fueglein | Positioning- and processing system for cultivation of root-crops and vegetables, includes GPS- or DGPS-controlled positioning and processing system mounted on trolley for placing crops in rows on ground |
US6560535B2 (en) * | 2000-01-05 | 2003-05-06 | The Johns Hopkins University | Global positioning system roadside integrated precision positioning system |
WO2001061271A2 (en) * | 2000-02-15 | 2001-08-23 | Prolink, Inc. | Map-matching golf navigation system |
US7366522B2 (en) | 2000-02-28 | 2008-04-29 | Thomas C Douglass | Method and system for location tracking |
US7218938B1 (en) | 2002-04-24 | 2007-05-15 | Chung Lau | Methods and apparatus to analyze and present location information |
US7905832B1 (en) | 2002-04-24 | 2011-03-15 | Ipventure, Inc. | Method and system for personalized medical monitoring and notifications therefor |
US7212829B1 (en) | 2000-02-28 | 2007-05-01 | Chung Lau | Method and system for providing shipment tracking and notifications |
US6697752B1 (en) | 2000-05-19 | 2004-02-24 | K&L Technologies, Inc. | System, apparatus and method for testing navigation or guidance equipment |
US6445983B1 (en) * | 2000-07-07 | 2002-09-03 | Case Corporation | Sensor-fusion navigator for automated guidance of off-road vehicles |
US6593879B1 (en) | 2000-08-10 | 2003-07-15 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Using the global positioning satellite system to determine attitude rates using doppler effects |
US6427122B1 (en) * | 2000-12-23 | 2002-07-30 | American Gnc Corporation | Positioning and data integrating method and system thereof |
US6641090B2 (en) * | 2001-01-10 | 2003-11-04 | Lockheed Martin Corporation | Train location system and method |
US6445990B1 (en) | 2001-03-19 | 2002-09-03 | Caterpillar Inc. | Method and apparatus for controlling straight line travel of a tracked machine |
JP5020437B2 (en) | 2001-03-21 | 2012-09-05 | 本田技研工業株式会社 | GPS receiver |
US6512976B1 (en) | 2001-04-27 | 2003-01-28 | Honeywell International Inc. | Method and system for terrain aided navigation |
DE10129136A1 (en) * | 2001-06-16 | 2002-12-19 | Deere & Co | Device for the automatic steering of an agricultural work vehicle |
US6593875B2 (en) * | 2001-06-29 | 2003-07-15 | Information Systems Laboratories, Inc. | Site-specific doppler navigation system for back-up and verification of GPS |
US6684157B2 (en) * | 2001-12-06 | 2004-01-27 | Yazaki North America, Inc. | Method and system for interfacing a global positioning system, other navigational equipment and wireless networks with a digital data network |
US7948769B2 (en) | 2007-09-27 | 2011-05-24 | Hemisphere Gps Llc | Tightly-coupled PCB GNSS circuit and manufacturing method |
US6577953B1 (en) | 2002-02-19 | 2003-06-10 | Motorola, Inc. | Device for use with a portable inertial navigation system (PINS) and method for processing PINS signals |
US7103457B2 (en) * | 2002-03-28 | 2006-09-05 | Dean Technologies, Inc. | Programmable lawn mower |
AU2003228377A1 (en) * | 2002-03-28 | 2003-10-13 | Jason Dean | Programmable lawn mower |
US7565155B2 (en) | 2002-04-10 | 2009-07-21 | Networks In Motion | Method and system for dynamic estimation and predictive route generation |
US6826478B2 (en) * | 2002-04-12 | 2004-11-30 | Ensco, Inc. | Inertial navigation system for mobile objects with constraints |
US9182238B2 (en) | 2002-04-24 | 2015-11-10 | Ipventure, Inc. | Method and apparatus for intelligent acquisition of position information |
US9049571B2 (en) | 2002-04-24 | 2015-06-02 | Ipventure, Inc. | Method and system for enhanced messaging |
US7210544B2 (en) | 2002-07-12 | 2007-05-01 | Deka Products Limited Partnership | Control of a transporter based on attitude |
US6711838B2 (en) | 2002-07-29 | 2004-03-30 | Caterpillar Inc | Method and apparatus for determining machine location |
US20040056182A1 (en) * | 2002-09-20 | 2004-03-25 | Jamieson James R. | Railway obstacle detection system and method |
DE10250694B3 (en) * | 2002-10-31 | 2004-02-12 | CNH Österreich GmbH | Agricultural vehicle control method provides automatic travel and field end management by detection, storage and controlled alteration of vehicle operating parameters |
US6907347B2 (en) * | 2002-11-21 | 2005-06-14 | Ford Global Technologies, Llc | Systems and method for estimating speed and pitch sensor errors |
US7689354B2 (en) * | 2003-03-20 | 2010-03-30 | Hemisphere Gps Llc | Adaptive guidance system and method |
US7142956B2 (en) * | 2004-03-19 | 2006-11-28 | Hemisphere Gps Llc | Automatic steering system and method |
US7400956B1 (en) | 2003-03-20 | 2008-07-15 | Hemisphere Gps Inc. | Satellite position and heading sensor for vehicle steering control |
US7885745B2 (en) | 2002-12-11 | 2011-02-08 | Hemisphere Gps Llc | GNSS control system and method |
US7162348B2 (en) | 2002-12-11 | 2007-01-09 | Hemisphere Gps Llc | Articulated equipment position control system and method |
US8265826B2 (en) * | 2003-03-20 | 2012-09-11 | Hemisphere GPS, LLC | Combined GNSS gyroscope control system and method |
US8634993B2 (en) | 2003-03-20 | 2014-01-21 | Agjunction Llc | GNSS based control for dispensing material from vehicle |
US8686900B2 (en) * | 2003-03-20 | 2014-04-01 | Hemisphere GNSS, Inc. | Multi-antenna GNSS positioning method and system |
US8594879B2 (en) | 2003-03-20 | 2013-11-26 | Agjunction Llc | GNSS guidance and machine control |
US8140223B2 (en) | 2003-03-20 | 2012-03-20 | Hemisphere Gps Llc | Multiple-antenna GNSS control system and method |
US8271194B2 (en) | 2004-03-19 | 2012-09-18 | Hemisphere Gps Llc | Method and system using GNSS phase measurements for relative positioning |
US8138970B2 (en) | 2003-03-20 | 2012-03-20 | Hemisphere Gps Llc | GNSS-based tracking of fixed or slow-moving structures |
US8190337B2 (en) | 2003-03-20 | 2012-05-29 | Hemisphere GPS, LLC | Satellite based vehicle guidance control in straight and contour modes |
US9002565B2 (en) | 2003-03-20 | 2015-04-07 | Agjunction Llc | GNSS and optical guidance and machine control |
US20040212533A1 (en) * | 2003-04-23 | 2004-10-28 | Whitehead Michael L. | Method and system for satellite based phase measurements for relative positioning of fixed or slow moving points in close proximity |
US8214111B2 (en) * | 2005-07-19 | 2012-07-03 | Hemisphere Gps Llc | Adaptive machine control system and method |
US6789014B1 (en) | 2003-05-09 | 2004-09-07 | Deere & Company | Direct modification of DGPS information with inertial measurement data |
EP1475609B1 (en) | 2003-05-09 | 2012-10-24 | Deere & Company | GPS / INS compensation system of a land vehicle |
US6694260B1 (en) * | 2003-05-09 | 2004-02-17 | Deere & Company | Inertial augmentation for GPS navigation on ground vehicles |
US6997120B2 (en) * | 2003-05-15 | 2006-02-14 | Robert Gabriel | Planting apparatus and method |
US20050015189A1 (en) * | 2003-07-14 | 2005-01-20 | New Holland North America, Inc. | Guidance system for towed farm implements |
US7346452B2 (en) * | 2003-09-05 | 2008-03-18 | Novatel, Inc. | Inertial GPS navigation system using injected alignment data for the inertial system |
WO2005029001A1 (en) * | 2003-09-23 | 2005-03-31 | Hydro-Quebec | Method and apparatus for determining the position of an underwater object in real-time |
US7593798B2 (en) * | 2003-10-30 | 2009-09-22 | Deere & Company | Vehicular guidance system having compensation for variations in ground elevation |
US20050176443A1 (en) * | 2004-02-09 | 2005-08-11 | J. Doss Halsey | Cellular phone geolocation system |
US8583315B2 (en) | 2004-03-19 | 2013-11-12 | Agjunction Llc | Multi-antenna GNSS control system and method |
US7509216B2 (en) * | 2004-03-29 | 2009-03-24 | Northrop Grumman Corporation | Inertial navigation system error correction |
US20060064222A1 (en) * | 2004-09-21 | 2006-03-23 | Accurtrak Systems Limited | Kit for providing an automatic steering system |
US7257483B2 (en) * | 2004-09-23 | 2007-08-14 | HYDRO-QUéBEC | Method and apparatus for determining the position of an underwater object in real-time |
US7574290B2 (en) * | 2004-11-30 | 2009-08-11 | Trimble Navigation Limited | Method and system for implementing automatic vehicle control with parameter-driven disengagement |
US7451029B2 (en) * | 2004-12-04 | 2008-11-11 | Cnh America Llc | Vehicle direction estimation using transmission control information |
US20060287824A1 (en) * | 2005-01-29 | 2006-12-21 | American Gnc Corporation | Interruption free navigator |
US7168174B2 (en) * | 2005-03-14 | 2007-01-30 | Trimble Navigation Limited | Method and apparatus for machine element control |
US7860628B2 (en) | 2005-06-09 | 2010-12-28 | Trimble Navigation Limited | System for guiding a farm implement between swaths |
JP2007024514A (en) * | 2005-07-12 | 2007-02-01 | Datatron:Kk | Vehicle-mounted information display device and vehicle information communication system using this |
CN1322311C (en) * | 2005-07-13 | 2007-06-20 | 李俊峰 | vehicle-carrying quick positioning and orienting method |
US7221316B2 (en) * | 2005-10-10 | 2007-05-22 | The Boeing Company | Control segment-based lever-arm correction via curve fitting for high accuracy navigation |
US7221317B2 (en) * | 2005-10-10 | 2007-05-22 | The Boeing Company | Space-based lever arm correction in navigational systems employing spot beams |
US7129889B1 (en) * | 2005-10-10 | 2006-10-31 | The Boeing Company | User segment-based lever arm correction via prescribed maneuver for high-accuracy navigation |
US7388539B2 (en) | 2005-10-19 | 2008-06-17 | Hemisphere Gps Inc. | Carrier track loop for GNSS derived attitude |
US7711483B2 (en) * | 2005-11-15 | 2010-05-04 | Sirf Technology, Inc. | Dead reckoning system |
US7404355B2 (en) * | 2006-01-31 | 2008-07-29 | Deere & Company | Tractor and baler combination with automatic baling and tractor halt control |
US10378896B2 (en) * | 2006-02-27 | 2019-08-13 | Trimble Inc. | Method and system for planning the path of an agricultural vehicle |
US9239376B2 (en) * | 2010-10-08 | 2016-01-19 | Telecommunication Systems, Inc. | Doppler aided inertial navigation |
US7844378B2 (en) | 2006-10-05 | 2010-11-30 | Trimble Navigation Limited | Farm apparatus having implement sidehill drift compensation |
US9746329B2 (en) * | 2006-11-08 | 2017-08-29 | Caterpillar Trimble Control Technologies Llc | Systems and methods for augmenting an inertial navigation system |
USRE48527E1 (en) | 2007-01-05 | 2021-04-20 | Agjunction Llc | Optical tracking vehicle control system and method |
US7835832B2 (en) | 2007-01-05 | 2010-11-16 | Hemisphere Gps Llc | Vehicle control system |
US8311696B2 (en) | 2009-07-17 | 2012-11-13 | Hemisphere Gps Llc | Optical tracking vehicle control system and method |
US8000381B2 (en) | 2007-02-27 | 2011-08-16 | Hemisphere Gps Llc | Unbiased code phase discriminator |
US8010261B2 (en) | 2007-05-23 | 2011-08-30 | Cnh America Llc | Automatic steering correction of an agricultural harvester using integration of harvester header row sensors and harvester auto guidance system |
US8180514B2 (en) * | 2007-05-23 | 2012-05-15 | Rocona, Inc. | Autonomous agriculture platform guidance system |
US8086405B2 (en) * | 2007-06-28 | 2011-12-27 | Sirf Technology Holdings, Inc. | Compensation for mounting misalignment of a navigation device |
US7808428B2 (en) | 2007-10-08 | 2010-10-05 | Hemisphere Gps Llc | GNSS receiver and external storage device system and GNSS data processing method |
US9002566B2 (en) | 2008-02-10 | 2015-04-07 | AgJunction, LLC | Visual, GNSS and gyro autosteering control |
WO2009126587A1 (en) | 2008-04-08 | 2009-10-15 | Hemisphere Gps Llc | Gnss-based mobile communication system and method |
US7958982B2 (en) * | 2008-04-29 | 2011-06-14 | Caterpilar Inc. | Cable guide having a signaling instrument |
US7793442B2 (en) * | 2008-04-29 | 2010-09-14 | Caterpillar Inc | Avoidance system for locating electric cables |
US8626441B2 (en) * | 2008-06-17 | 2014-01-07 | Agco Corporation | Methods and apparatus for using position/attitude information to enhance a vehicle guidance system |
US20100023222A1 (en) * | 2008-07-22 | 2010-01-28 | Trimble Navigation Limited | System and Method for Location Based Guidance Controller Configuration |
US8401744B2 (en) * | 2008-07-22 | 2013-03-19 | Trimble Navigation Limited | System and method for configuring a guidance controller |
US8515626B2 (en) * | 2008-07-22 | 2013-08-20 | Trimble Navigation Limited | System and method for machine guidance control |
US9816821B2 (en) * | 2008-09-04 | 2017-11-14 | Apple Inc. | Location systems for handheld electronic devices |
US8112201B2 (en) * | 2008-10-02 | 2012-02-07 | Trimble Navigation Limited | Automatic control of passive, towed implements |
US8116977B2 (en) * | 2008-10-02 | 2012-02-14 | Trimble Navigation Limited | Automatic control of passive, towed implements |
US8217833B2 (en) | 2008-12-11 | 2012-07-10 | Hemisphere Gps Llc | GNSS superband ASIC with simultaneous multi-frequency down conversion |
US8386129B2 (en) * | 2009-01-17 | 2013-02-26 | Hemipshere GPS, LLC | Raster-based contour swathing for guidance and variable-rate chemical application |
US8085196B2 (en) | 2009-03-11 | 2011-12-27 | Hemisphere Gps Llc | Removing biases in dual frequency GNSS receivers using SBAS |
US8296065B2 (en) * | 2009-06-08 | 2012-10-23 | Ansaldo Sts Usa, Inc. | System and method for vitally determining position and position uncertainty of a railroad vehicle employing diverse sensors including a global positioning system sensor |
US8401704B2 (en) | 2009-07-22 | 2013-03-19 | Hemisphere GPS, LLC | GNSS control system and method for irrigation and related applications |
US8174437B2 (en) | 2009-07-29 | 2012-05-08 | Hemisphere Gps Llc | System and method for augmenting DGNSS with internally-generated differential correction |
US8248301B2 (en) * | 2009-07-31 | 2012-08-21 | CSR Technology Holdings Inc. | Method and apparatus for using GPS satellite state computations in GLONASS measurement processing |
US8334804B2 (en) | 2009-09-04 | 2012-12-18 | Hemisphere Gps Llc | Multi-frequency GNSS receiver baseband DSP |
US8649930B2 (en) | 2009-09-17 | 2014-02-11 | Agjunction Llc | GNSS integrated multi-sensor control system and method |
PT104783B (en) * | 2009-10-13 | 2014-08-27 | Univ Aveiro | HIGH PRECISION POSITIONING SYSTEM ADAPTED TO A TERRESTRIAL MOBILE PLATFORM |
US8548649B2 (en) | 2009-10-19 | 2013-10-01 | Agjunction Llc | GNSS optimized aircraft control system and method |
US8332106B2 (en) * | 2009-10-21 | 2012-12-11 | Caterpillar Inc. | Tether tracking system and method for mobile machine |
US8566032B2 (en) * | 2009-10-30 | 2013-10-22 | CSR Technology Holdings Inc. | Methods and applications for altitude measurement and fusion of user context detection with elevation motion for personal navigation systems |
CA2721892A1 (en) * | 2009-11-19 | 2011-05-19 | James Roy Bradley | Device and method for disabling mobile devices |
US8583326B2 (en) | 2010-02-09 | 2013-11-12 | Agjunction Llc | GNSS contour guidance path selection |
RU2010124265A (en) * | 2010-06-16 | 2011-12-27 | Алексей Владиславович Жданов (RU) | METHOD AND DEVICE FOR DETERMINING THE DIRECTION OF THE START OF MOTION |
CN101900573B (en) * | 2010-07-15 | 2011-12-07 | 北京理工大学 | Method for realizing landtype inertial navigation system movement aiming |
BR112013001287B1 (en) | 2010-07-20 | 2021-02-17 | Leica Geosystems Ag | system and method for determining unambiguous direction of travel of a vehicle |
CN101949955B (en) * | 2010-08-11 | 2012-05-16 | 北京交大资产经营有限公司 | State self-checking method of combined speed measuring and positioning system for train |
US8395542B2 (en) | 2010-08-27 | 2013-03-12 | Trimble Navigation Limited | Systems and methods for computing vertical position |
US8903677B2 (en) * | 2011-03-04 | 2014-12-02 | Msa Technology, Llc | Inertial navigation units, systems, and methods |
US8494726B2 (en) | 2011-05-16 | 2013-07-23 | Trimble Navigation Ltd. | Agricultural autopilot path adjustment |
DE102011052705A1 (en) † | 2011-08-15 | 2013-02-21 | Amazonen-Werke H. Dreyer Gmbh & Co. Kg | Agricultural distributor |
EP2755869B1 (en) * | 2011-09-12 | 2017-07-12 | Continental Teves AG & Co. oHG | Orientation model for a sensor system |
US8644113B2 (en) * | 2011-09-30 | 2014-02-04 | Microsoft Corporation | Sound-based positioning |
CN103033184B (en) * | 2011-09-30 | 2014-10-15 | 迈实电子(上海)有限公司 | Error correction method, device and system for inertial navigation system |
US9380741B2 (en) | 2011-12-28 | 2016-07-05 | Husqvarna Ab | Yard maintenance vehicle route and orientation mapping system |
CN102589569A (en) * | 2012-01-17 | 2012-07-18 | 北京理工大学 | Method for calibrating data of two point positions of marine aided inertial navigation system |
US9123034B2 (en) * | 2012-04-23 | 2015-09-01 | Transparent Wireless Systems, Llc | Methods and systems for electronic payment for parking using autonomous position sensing |
US10068386B2 (en) | 2012-04-23 | 2018-09-04 | Transparent Wireless Systems, Llc | Methods and systems for electronic payment for parking in gated garages |
US10096172B2 (en) | 2012-04-23 | 2018-10-09 | Transparent Wireless Systems, Llc | Methods and systems for electronic payment for on-street parking |
US8972166B2 (en) | 2012-07-17 | 2015-03-03 | Lockheed Martin Corporation | Proactive mitigation of navigational uncertainty |
US8781685B2 (en) | 2012-07-17 | 2014-07-15 | Agjunction Llc | System and method for integrating automatic electrical steering with GNSS guidance |
US9127955B2 (en) * | 2013-01-31 | 2015-09-08 | GM Global Technology Operations LLC | Adaptive user guidance for navigation and location-based services |
US10149430B2 (en) * | 2013-02-20 | 2018-12-11 | Husqvarna Ab | Robotic work tool configured for improved turning in a slope, a robotic work tool system, and a method for use in the robot work tool |
US8924099B2 (en) | 2013-03-12 | 2014-12-30 | Raven Industries, Inc. | System and method for determining implement train position |
US8825263B1 (en) | 2013-03-12 | 2014-09-02 | Raven Industries, Inc. | Vehicle guidance based on tractor position |
US10845452B2 (en) * | 2013-05-08 | 2020-11-24 | Cm Hk Limited | Hybrid positioning method, electronic apparatus and computer-readable recording medium thereof |
US9733643B2 (en) | 2013-12-20 | 2017-08-15 | Agjunction Llc | Hydraulic interrupter safety system and method |
JP6409346B2 (en) * | 2014-06-04 | 2018-10-24 | 株式会社デンソー | Moving distance estimation device |
US9454153B2 (en) | 2014-11-24 | 2016-09-27 | Trimble Navigation Limited | Farm vehicle autopilot with automatic calibration, tuning and diagnostics |
KR102172145B1 (en) * | 2015-06-05 | 2020-10-30 | 한국전자통신연구원 | Tightly-coupled localization method and apparatus in dead-reckoning system |
KR20170000282A (en) * | 2015-06-23 | 2017-01-02 | 한국전자통신연구원 | Robot position accuracy information providing apparatus using a sensor and method therefor |
US10783506B2 (en) | 2015-08-28 | 2020-09-22 | Transparent Wireless Systems, Llc | Methods and systems for access control to secure facilities |
US10042361B2 (en) * | 2015-12-07 | 2018-08-07 | Beijing Unistrong Science & Technology Co., Ltd. | System and method for terrestrial vehicle navigation |
CN105823481B (en) * | 2015-12-21 | 2019-02-12 | 上海华测导航技术股份有限公司 | A kind of GNSS-INS vehicle method for determining posture based on single antenna |
CA3015608A1 (en) | 2016-02-23 | 2017-08-31 | Deka Products Limited Partnership | Mobility device control system |
US10926756B2 (en) | 2016-02-23 | 2021-02-23 | Deka Products Limited Partnership | Mobility device |
US10908045B2 (en) | 2016-02-23 | 2021-02-02 | Deka Products Limited Partnership | Mobility device |
US10802495B2 (en) | 2016-04-14 | 2020-10-13 | Deka Products Limited Partnership | User control device for a transporter |
US11399995B2 (en) | 2016-02-23 | 2022-08-02 | Deka Products Limited Partnership | Mobility device |
CN107462242B (en) * | 2016-06-06 | 2020-09-29 | 千寻位置网络有限公司 | Vehicle speed measuring method and device |
CN106123926B (en) * | 2016-08-25 | 2019-03-05 | 哈尔滨工程大学 | A kind of UUV based on GPS information amendment inertial navigation location error marks on a map method offline |
BR112019006526A2 (en) | 2016-10-03 | 2019-06-25 | Agjunction Llc | control system to gather data from different sensors and determine a vehicle orientation and computer program to calculate a vehicle direction |
WO2018075397A1 (en) | 2016-10-17 | 2018-04-26 | Agjunction Llc | An actuator for turning a steering wheel in automatic steering systems |
EP3570652B1 (en) | 2017-01-19 | 2022-12-21 | Agjunction LLC | Low cost implement positioning |
USD846452S1 (en) | 2017-05-20 | 2019-04-23 | Deka Products Limited Partnership | Display housing |
USD829612S1 (en) | 2017-05-20 | 2018-10-02 | Deka Products Limited Partnership | Set of toggles |
US11280896B2 (en) | 2017-06-16 | 2022-03-22 | FLIR Belgium BVBA | Doppler GNSS systems and methods |
EP3803736A1 (en) | 2018-06-07 | 2021-04-14 | DEKA Products Limited Partnership | System and method for distributed utility service execution |
CN110793514B (en) * | 2018-08-02 | 2024-03-01 | 菜鸟智能物流控股有限公司 | Position measuring method and position measuring device |
US11178805B2 (en) * | 2019-07-05 | 2021-11-23 | Deere & Company | Apparatus and methods for vehicle steering to follow a curved path |
RU2718131C1 (en) * | 2019-08-08 | 2020-03-30 | Федеральное государственное бюджетное военное образовательное учреждение высшего образования "Черноморское высшее военно-морское ордена Красной Звезды училище имени П.С. Нахимова" Министерства обороны Российской Федерации | Method for radar measurement of sea vehicle (ship) hull vibration |
DE102019218530B4 (en) * | 2019-11-29 | 2021-07-22 | Zf Friedrichshafen Ag | Method for determining a position of a motor vehicle |
US11686836B2 (en) * | 2020-01-13 | 2023-06-27 | Pony Ai Inc. | Real-time and dynamic localization using active doppler sensing systems for vehicles |
US11914379B2 (en) | 2020-12-23 | 2024-02-27 | Deere & Company | Methods and apparatus to generate a path plan |
Family Cites Families (64)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4870422A (en) * | 1982-03-01 | 1989-09-26 | Western Atlas International, Inc. | Method and system for determining position from signals from satellites |
US4860018A (en) * | 1982-03-01 | 1989-08-22 | Western Atlas International, Inc. | Continuous wave interference rejection for reconstructed carrier receivers |
US5194871A (en) * | 1982-03-01 | 1993-03-16 | Western Atlas International, Inc. | System for simultaneously deriving position information from a plurality of satellite transmissions |
US4667203A (en) * | 1982-03-01 | 1987-05-19 | Aero Service Div, Western Geophysical | Method and system for determining position using signals from satellites |
US5143073A (en) * | 1983-12-14 | 1992-09-01 | Edap International, S.A. | Wave apparatus system |
US5150712A (en) * | 1983-12-14 | 1992-09-29 | Edap International, S.A. | Apparatus for examining and localizing tumors using ultra sounds, comprising a device for localized hyperthermia treatment |
US4796191A (en) * | 1984-06-07 | 1989-01-03 | Etak, Inc. | Vehicle navigational system and method |
US4599620A (en) * | 1984-12-04 | 1986-07-08 | The United States Of America As Represented By The Secretary Of The Navy | Method for determining the orientation of a moving platform |
US4878170A (en) * | 1987-03-17 | 1989-10-31 | Zeevi Eliahu I | Vehicle navigation system |
JPH0820504B2 (en) * | 1987-09-22 | 1996-03-04 | 株式会社豊田中央研究所 | GPS navigation device |
WO1989006342A1 (en) * | 1987-12-28 | 1989-07-13 | Aisin Aw Co., Ltd. | Vehicle navigation system |
FR2626677B1 (en) * | 1988-02-01 | 1990-06-22 | Thomson Csf | RADIONAVIGATION SYSTEM |
CA1321418C (en) * | 1988-10-05 | 1993-08-17 | Joseph C. Mcmillan | Primary land arctic navigation system |
SU1693602A1 (en) * | 1988-11-04 | 1991-11-23 | Ю.А. Ганушкин, К.И. Кучеренко и А.В. Никити | Device for computing modulus of difference of two numbers |
SU1624449A1 (en) * | 1988-12-07 | 1991-01-30 | Пушкинское высшее училище радиоэлектроники противовоздушной обороны | Device for connecting data sources to a common bus |
DE3914301A1 (en) * | 1989-04-29 | 1990-10-31 | Bruker Medizintech | METHOD FOR RECORDING SPIN RESONANCE SPECTRA AND FOR SPIN RESONANCE IMAGING |
US5299130A (en) * | 1989-05-01 | 1994-03-29 | Toyoichi Ono | Apparatus for controlling movement of vehicle |
JP2913097B2 (en) * | 1989-06-01 | 1999-06-28 | ヤンマー農機株式会社 | Steering control device |
SU1661826A1 (en) * | 1989-07-03 | 1991-07-07 | Научно-исследовательский институт авиационного оборудования | Graphic data tv display unit |
DE3922428A1 (en) * | 1989-07-07 | 1991-01-17 | Deutsche Forsch Luft Raumfahrt | METHOD FOR THE EXTRACTION OF MOTION ERRORS OF A CARRIER CARRYING OUT A RADAR RAW DATA WITH A COHERENT IMAGE RADAR SYSTEM AND DEVICE FOR IMPLEMENTING THE METHOD |
US5177489A (en) * | 1989-09-26 | 1993-01-05 | Magnavox Electronic Systems Company | Pseudolite-aided method for precision kinematic positioning |
WO1991009375A1 (en) * | 1989-12-11 | 1991-06-27 | Caterpillar Inc. | Integrated vehicle positioning and navigation system, apparatus and method |
US5382957A (en) * | 1989-12-19 | 1995-01-17 | The United States Of America As Represented By The Secretary Of The Navy | System and method |
US5390125A (en) * | 1990-02-05 | 1995-02-14 | Caterpillar Inc. | Vehicle position determination system and method |
US5214757A (en) * | 1990-08-07 | 1993-05-25 | Georesearch, Inc. | Interactive automated mapping system |
JP2873872B2 (en) * | 1990-09-06 | 1999-03-24 | 株式会社ソキア | C / A code removal type frequency diversity correlation reception system in GPS |
US5344144A (en) * | 1990-09-27 | 1994-09-06 | Mikohn, Inc. | Progressive jackpot gaming system with enhanced accumulator |
US5155490A (en) * | 1990-10-15 | 1992-10-13 | Gps Technology Corp. | Geodetic surveying system using multiple GPS base stations |
IL95990A (en) * | 1990-10-15 | 1994-07-31 | B V R Technologies Ltd | Anti-collision warning system |
FR2669118B1 (en) * | 1990-11-13 | 1993-04-02 | Geophysique Cie Gle | DEVICE FOR RECORDING AND PROCESSING MARINE MAGNETISM DATA. |
US5030957A (en) * | 1991-02-26 | 1991-07-09 | The United States Of America As Represented By The Secretary Of The Navy | Method of simultaneously measuring orthometric and geometric heights |
US5202829A (en) * | 1991-06-10 | 1993-04-13 | Trimble Navigation Limited | Exploration system and method for high-accuracy and high-confidence level relative position and velocity determinations |
US5523951A (en) * | 1991-09-06 | 1996-06-04 | The United States Of America As Represented By The Secretary Of The Navy | System and method for automatic ship steering |
US5347286A (en) * | 1992-02-13 | 1994-09-13 | Trimble Navigation Limited | Automatic antenna pointing system based on global positioning system (GPS) attitude information |
US5323322A (en) * | 1992-03-05 | 1994-06-21 | Trimble Navigation Limited | Networked differential GPS system |
US5291412A (en) * | 1992-03-24 | 1994-03-01 | Zexel Corporation | Navigation system |
DE69314219T2 (en) * | 1992-04-20 | 1998-03-12 | Sumitomo Electric Industries | Device for detecting the course of the vehicle |
US5220876A (en) * | 1992-06-22 | 1993-06-22 | Ag-Chem Equipment Co., Inc. | Variable rate application system |
US5442558A (en) * | 1992-08-06 | 1995-08-15 | Caterpillar Inc. | Method and system for determining vehicle position based on a projected position of a satellite |
FR2697655B1 (en) * | 1992-10-30 | 1994-12-02 | Renault | Method and device for guiding a vehicle on a traffic plane. |
US5430654A (en) * | 1992-12-01 | 1995-07-04 | Caterpillar Inc. | Method and apparatus for improving the accuracy of position estimates in a satellite based navigation system |
US5390124A (en) * | 1992-12-01 | 1995-02-14 | Caterpillar Inc. | Method and apparatus for improving the accuracy of position estimates in a satellite based navigation system |
GB9300305D0 (en) * | 1993-01-08 | 1993-03-10 | Short Brothers Plc | Aerodynamic pressure sensor systems |
JPH06225231A (en) * | 1993-01-26 | 1994-08-12 | Toshiba Corp | On-vehicle display device |
DE4304561A1 (en) * | 1993-02-16 | 1994-08-18 | Deutsche Aerospace | Device for preventing aircraft from accidentally coming into contact with the ground and obstructions in the close vicinity of airports |
US5379320A (en) * | 1993-03-11 | 1995-01-03 | Southern California Edison Company | Hitless ultra small aperture terminal satellite communication network |
JP3329817B2 (en) * | 1993-03-12 | 2002-09-30 | シチズン時計株式会社 | Electronic equipment with water depth measurement function |
FR2703200B1 (en) * | 1993-03-26 | 1995-08-18 | Obadia Alain | COMMUNICATION METHOD AND INSTALLATION FOR FLEET OF TAXIS. |
US5606506A (en) * | 1993-04-05 | 1997-02-25 | Caterpillar Inc. | Method and apparatus for improving the accuracy of position estimates in a satellite based navigation system using velocity data from an inertial reference unit |
US5420593A (en) * | 1993-04-09 | 1995-05-30 | Trimble Navigation Limited | Method and apparatus for accelerating code correlation searches in initial acquisition and doppler and code phase in re-acquisition of GPS satellite signals |
US5392052A (en) * | 1993-04-28 | 1995-02-21 | Eberwine; Mark A. | Position reporting emergency location system |
US5587904A (en) * | 1993-06-10 | 1996-12-24 | Israel Aircraft Industries, Ltd. | Air combat monitoring system and methods and apparatus useful therefor |
US5534875A (en) * | 1993-06-18 | 1996-07-09 | Adroit Systems, Inc. | Attitude determining system for use with global positioning system |
DE4342171C2 (en) * | 1993-07-17 | 1996-01-25 | Georg Duerrstein | Soil preparation methods, in particular for fertilizing agricultural land |
US5517419A (en) * | 1993-07-22 | 1996-05-14 | Synectics Corporation | Advanced terrain mapping system |
US5438337A (en) * | 1993-09-24 | 1995-08-01 | Northrop Grumman Corporation | Navigation system using re-transmitted GPS |
US5422814A (en) * | 1993-10-25 | 1995-06-06 | Trimble Navigation Limited | Global position system receiver with map coordinate system outputs |
WO1995018432A1 (en) * | 1993-12-30 | 1995-07-06 | Concord, Inc. | Field navigation system |
JPH07230315A (en) * | 1994-02-16 | 1995-08-29 | Fuji Heavy Ind Ltd | Traveling controller for autonomously traveling vehicle |
US5617317A (en) * | 1995-01-24 | 1997-04-01 | Honeywell Inc. | True north heading estimator utilizing GPS output information and inertial sensor system output information |
US5592382A (en) * | 1995-03-10 | 1997-01-07 | Rockwell International Corporation | Directional steering and navigation indicator |
DE19513244A1 (en) * | 1995-04-07 | 1996-10-10 | Honeywell Ag | Fault-tolerant train platform |
US5657025A (en) * | 1995-08-07 | 1997-08-12 | Litton Systems, Inc. | Integrated GPS/inertial navigation apparatus providing improved heading estimates |
DE19604812C1 (en) * | 1995-12-13 | 1996-12-12 | Hoelzl Hans | Automatic spreading machine for manure and sewage |
-
1996
- 1996-02-05 US US08/596,957 patent/US5928309A/en not_active Expired - Lifetime
-
1997
- 1997-02-14 CA CA002279877A patent/CA2279877C/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021233388A1 (en) * | 2020-05-21 | 2021-11-25 | 深圳市海柔创新科技有限公司 | Navigation method and navigation apparatus |
Also Published As
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US5928309A (en) | 1999-07-27 |
CA2279877A1 (en) | 1998-08-20 |
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