CA2175945C - Integrated gps/inertial navigation apparatus providing improved heading estimates - Google Patents
Integrated gps/inertial navigation apparatus providing improved heading estimatesInfo
- Publication number
- CA2175945C CA2175945C CA002175945A CA2175945A CA2175945C CA 2175945 C CA2175945 C CA 2175945C CA 002175945 A CA002175945 A CA 002175945A CA 2175945 A CA2175945 A CA 2175945A CA 2175945 C CA2175945 C CA 2175945C
- Authority
- CA
- Canada
- Prior art keywords
- phase
- time period
- signal
- inertial navigation
- navigation system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- 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
-
- 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
- G01S19/53—Determining attitude
- G01S19/54—Determining attitude using carrier phase measurements; using long or short baseline interferometry
-
- 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
-
- 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
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/32—Multimode operation in a single same satellite system, e.g. GPS L1/L2
Abstract
The integrated GPS/inertial navigation apparatus utilizes satellite signals received with two spatially-separated antennas to achieve improved heading estimates for a mobile platform. Each satellite signal comprises one or more component signals with each component signal having a different carrier frequency. The integrated GPS/inertial navigation apparatus consists of a receiver and an inertial navigation system. The receiver measures the carrier phase of each of one or more component signals of one or more satellite signals received by each of the two antennas during successive time periods of duration Tp. Phase measured during a Tp time period is called Tp-phase. Only one component signal of one satellite signal received by one antenna is measured during any Tp time period. The receiver utilizes the Tp-phases of each component signal obtained during a Tk time period to estimate the phase of the component signal at the end of the Tk time period, the estimated phase at the end of the Tk time period being called the Tk-phase. The inertial navigation system, comprising inertial sensors and a digital processor, utilizes the Tk-phases in determining the heading of the vehicle and the displacement of each of the two antennas from the inertial sensors of the inertial navigation system. The measured phase of a component signal is subject to error as a result of the satellite signal traversing the ionosphere.
The inertial navigation system achieves more accurate estimates of heading and antenna displacements by utilizing the Tk-phases in determining ionospheric corrections to phase.
The inertial navigation system achieves more accurate estimates of heading and antenna displacements by utilizing the Tk-phases in determining ionospheric corrections to phase.
Description
DESCRIPTION
INTEGRATED GPS/INERTIAL NAVIGATION APPARATUS
PROVIDING IMPROVED HEADING ESTIMATES
TECHNICAL FIELD
This invention relates generally to methods and apphld~us for lltili7ing satellite signals in 10 combination with an inertial navigation system (INS)to determine vehicle heading. More specifically, the invention relates to the use of signals transmitted by a Global Positioning System (GPS) satellite and lNSs which utilize gyros with bias eITors ranging up to one degree per hour.
BACKGROUND ART
Position, velocity, and attitude of a vehicle can be accurately determined using well-known methods of coupling GPS receiver/processors and INSs. Accurately detenninin~ the he~-ling of a vehicle under all conditions of motion, however, requires either a long period of time for 20 gyrocompassing in the case of medium-accuracy INSs (i.e. gyro bias errors of ~0.01 degrees/hour) or the use of a magnetic detector such as a flux valve in the case of low-accuracy INSs (i.e. gyro bias errors of~ 1 degree/hour).
INS measulelllents of hçading can be corrected by utili7ing GPS measurements of vehicle position and velocit,v when vehicle maneuvering is taking place. However, in the case of a low-25 accuracy INS, errors in hP~-iing during periods without turns or ~cceler~tions grow as a result of gyro drift--potentially one degree for every hour of non-acceleration--or be limited to about one degree by the errors in the flux valve.
Another approach is to use two GPS receivers having a common time reference with two ~ntenn~ to derive the phase differences between GPS carrier phase as received by the ~ntenn~
The phase differences and knowledge of the GPS satellite positions as determined by their ephemerides and time can then be used with INS pitch and roll to determine vehicle heading.
Because of the periodicity of the carrier phase, ambiguities arise and various methods have been devised to resolve them. The need for two receivers entails an undesirable cost penalty, S especially when used with a low-cost INS.
DISCLOSURE OF INVENTION
10 The integrated GPS/inertial navigation apparatus is for use with two spatially-separated antennas on a mobile platform, the two antçnn~ being capable of receiving signals from one or more satellites. Each satellite signal comprises one or more component signals with each component signal having a different carrier frequency. The integrated GPS/inertial navigation apparatus consists of a receiver and an inertial navigation system.
15 The receiver measures the carrier phase of each of one or more component signals of one or more satellite signals received by each of the two antennas during successive time periods of duration Tp. Phase measured during a Tp time period is called Tp-phase. Only one component signal of one satellite signal received by one antenna is measured during any single time period.
The receiver utilizes the Tp-phases of each component signal obtained during a Tk time period 20 to estimate the phase of the component signal at the end of the Tk time period, the estimated phase at the end of the Tk time period being called the Tk-phase.
The inertial navigation system, comprising inertial sensors and a digital processor, utilizes the Tk-phases in cletçrmining the h~ling of the vehicle. The inertial navigation system also utili~ the Tk-phases in det~rmining the displacement of each of the t~,vo ~nt~nn~c from the 25 inertial sensors of the inertial navigation system. The measured phase of a component signal is subject to error as a result of the satellite signal traversing the ionosphere. The inertial navigation system achieves more accurate estim~t~?s of heading and antenna displ~cçment~ by utili7ing the Tk-phases in determining the ionospheric corrections.
~ 7 59~5 .,~
BRIEF DESCRIPI ION OF DRAWINGS
FIG. I is a block diagram of the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The preferred embodiment of the invention is shown in Fig. 1 and consists of two antennas 1 and 3, a switched-channel GPS receiver 5 and an inertial navigation system (INS) 7. The two 10 spatially-separated omnidirectional ~nt~nn~c 1 and 3 are designed to receive the GPS navigation signals l~ lilled by the GPS satellites at frequencies Ll (IS75.42 MHz) and L2 (1227.6 MHz).
The antennas are mounted on a platform in such a way that the projections of the phase centers of the two antennas onto a nominally level plane are at least one meter apart. This separation could be achieved on an aircraft, for example, by either mounting the antennas along 15 the top of the fuselage or on one or both of the wings. On a land or sea vehicle, any part of the structure could be used as long as the one-meter separation of the projection of the antenna locations to a nominally horizontal plane is provided with a reasonably unobstructed view of the sky. The antennas need not physically be in a nominally horizontal plane, however. One may be higher than the other.
20 The antennas should be attached to ground planes to m~int~in good control of the phase centers of the antennas at all viewing angles to the satellites. Reflections received from other parts of the vehicle should also be minimi7.o~1 for optimum performance.
The navigation signals received by ~nt~nn~ I feed into RF channels 9 and 11, and those received by ~ntt nn~ 3 feed into RF channels 13 and 15 . RF channels 9 and 13 pass only the L 1 25 signal colnpollel~t while RF r l~nn~!s 1 1 and 15 pass only the L2 signal component. The outputs of the four RF channels feed into the switch 17.
The single output of the switch 17 feeds into a down-converter 19 which tr~n~!~tes the frequency of the input signal, under the control signal appearing on conductor 21, to a fixed IF.
The output of the down converter 19 feeds into the signal digitizer 23.
30 The signal digitizer 23 samples in-phase and quadrature components of the input signal at twice 2 1 7 5'~45 the code chipping rate and supplies these in-phase and quadrature digitized samples to the receiver processor 25 which performs a number of functions among which is the estimation of carrier phase.
The down-converter 19, the signal digitizer 23, and the receiver processor 25 (insofar as the 5 basic functions required for deriving navigation information, including the estimation of pseudorange, delta pseudorange, and carrier phase) are described in greater detail in U.S. Patent No. 4,807,256.
The receiver processor 25, by means of a control signal on line 27, causes the switch 17 to periodically and repetitively sequence its four input signals to its output thereby obtaining 10 pseudorange, delta pseudorange, and carrier phase for the four combinations of Antçnn~ and frequency during each repetition cycle. Pseudorange Rp is defined by the equation R = R + c(~t- ~T) + /~R jon + ~RtroP (1) where R is the actual range from the antenna to the satellite, c is the propagation speed of the radio waves in vacuum, ~t is the satellite clock error, ~T is the user clock error, ~Rjon and ~Rtrop are ionospheric and tropospheric corrections which account for the difference in propagation speed of radio waves through the ionosphere and troposphere respectively as 20 compared to a vacuum.
Delta pseudorange is the change in pseudorange over a specified time interval and is equal to the time rate of change of actual range adjusted for the difference in satellite clock rate error and user clock rate error and is equivalent to the measured Doppler shift in the carrier frequency of the received satellite signal.
25 Carrier phase ~ is defined by the equation (2) ~ = R + c(~t-~T) - N~ + /\Rion + ~Rtrop 30 where ~ is the radio-wave wavelength and N is an integer such that ~ is constrained to a one-21 759~
'~_ wavelength range.
The Kalman filter 29 located in the inertial navigation system 7 supplies to the receiver processor 25 computed user clock error and user clock rate error. The receiver processor 25 adds the computed user clock error to its estimates of pseudorange and carrier phase and adds the 5 computed user clock rate error to its estimates of delta pseudorange to obtain user clock adjusted (UCA) estimates. These UCA pseudoranges, delta pseudoranges, and carrier phases are supplied by the receiver processor 25 to the Kalman filter 29.
The receiver processor 25 extracts satellite ephemeris data, satellite clock and clock rate errors, and synchronization data from the satellite signals and supplies this data to range 10 processor 31 in the inertial navigation system 7.
The inertial measurement unit (IMU) 33, a Litton LN-200 model, supplies to navigation processor 35 in the inertial navigation system 7 platform acceleration measured by accelerometers fixed to the platform and platform angular rotation rate measured by gyros also fixed to the platform. This data is corrected by the navigation processor 35 for accelerometer and 15 gyro bias, scale factor error, and mi~lignment using data supplied by the Kalman filter 29.
A barometric altimeter 37 provides a platform altitude input to navigation processor 35.
Corrections for altimeter bias and scale factor errors are supplied to the navigation processor 35 by the Kalman filter 29.
The navigation processor 35 uses the platform acceleration, angular rotation rate, and altitude 20 to periodically compute the position, velocity, and attitude of the platform. These quantities are corrected with data supplied by the Kalman filter 29, and the corrected data is passed on to the range processor 31.
The range processor 31 uses this corrected data together with ~nt~nn~ displacements (corrected in accordance with the ~ntPnn~ displacement errors supplied by the Kalman filter 29) 25 and the satellite ephemeris data to obtain computed ranges, delta ranges, and carrier phases. The range processor 31 adds the satellite clock error, the ionospheric correction, and the tropospheric correction to each computed range thereby obtaining a quantity analogous to the UCA
pseudorange supplied to the Kalman filter 29 by the receiver processor 25.
The ionospheric correction is det~rmined from an equation involving an ionospheric 30 parameter (the error in the ionospheric parameter being determined by the Kalman filter 29 and supplied to the range processor). The tropospheric correction is computed by the range processor ~ ~ 7~45 31 rrom the epllemcris data and tlle location of the user's vehicle.
The range processor 31 also adds satellite clock rate error to each computed delta range thereby obtaining a quantity analogous to the UCA delta pseudorange supplied by the receiver processor 25 to the Kalman filter 29. The range processor 31 also subtracts Nl from each UCA
5 pseudorange analog to obtain a quantity analogous to UCA carrier phase. These computed UCA
pseudorange analogs, computed UCA delta range analogs, and computed UCA carrier phase analogs are supplied to the Kalman filter 29.
The determination of N can be accomplished in any one of a number of ways. Examples are given by Knight in U.S. Pat. No. 5,296,861, by Ward et al. in U.S. Pat. No. 5,185,610, and by 10 Hatch in U.S. Pat. No. 5,072,227.
The Kalman filter 29 obtains a minim~l mean-square-error solution of the navigation problem and supplies corrections to the input data in anticipation of the next iteration of the Kalman process. The Kalman process is well-known and will not be described here since it is described in detail in a number of textbooks, one example being A. Gelb, ed., Applied Optimal l~slin7ation, 15 The Analytical Sciences Corporation, The M.l.T. Press, Cambridge, Mass., 1974.
Tlle vehicle states used by the Kalman filter 29 number 42 and consist of two level position states, one heading state, three velocity states, three attitude states, one altitude state, three accelerometer bias states, three accelerometer scale factor states, six accelerometer misalignment states, tllree gyro bias states, tllree gyro scale factor states, tllree gyro misalignment states, one 20 barometric altimeter bias state, one barometric altimeter scale factor state, one user clock phase statc, one user clock fi equency state, one iollosplleric parameter state, and six antelllla displacement states.
The time Tk typically required to execute a Kalman filter iteration is several seconds. The switching cycle for the switch 17 in Fig. 1 may be as long 4Tk, in which case the receiver 25 processor 25 provides an estimate of the carrier phase for one frequency and one antenna coincident with the beginning of a Kalman filter iteration. The receiver processor 25 may produce carrier phase estimates at Tp intervals where Tp may be as short as a millisecond, in which case the carrier phase estimate for a particular frequency and for a particular antenna produced at the beginning of each Tk, interval would be calculated using all of the carrier phase 30 estimates for the particular frequency and for the particular frequency and for the particular antenna obtained during the prior Tk interval. However, only one new carrier phase estimate for each frequency and for each antenna would enter the Kalman filter process during each 2 4~ 7 ~
, ....
iteration. Tlle yroccdurc for dclern~ining thc phasc at the end of a time period usin~ pllase measurements obtained during ~he time illlerval is a strai~lltforward and well-understoo(l slalislieal proce(3ule and is described ill many lexlbooks.
Ihe swilcl~ cycle l'or llle swilcll 17 nlay be as sllorl as 41~" in wllicll casc Ille rceeivcl 5 proecssor 25 woukl provide four carrier pllase estilllales al lhe be~imlillL~ of cacll J k illlerva~ le receiver processor 25 would calculate lllc earrier pll.lse eslinlale lor a parlicular ~'reqllcllcy alld a particular anle~ a delivered at llle begilmitlg of a Tk inlerval using all ol tl~e pllase estilllales corrcspondillg lo lllc salnc rrcqucncy and llle salnc anlclllla oblaincd dulillg lllc pliOI' 'I'k illlclval.
The switclling eycle can of course ran~,e anywllere belween 4T~, and 41 k.
10 Tlle preferred embodilllenl is a syslem in whicll llle swilehill~ cycle results ill llle seleclio Or si~,nals of rrequency L I an(l L2 from eaeh of lhe lwo anlemlas. ln allo(ller enlbodilllelll, llle s~ cl~ , cyclc woul~J cyclc l)ClWCCIl lwo .ullcllllas wi~ llc Si~ll.ll Iic~lucllcy .IIW.lyS l)~ , cil~
L l or L2, in whicll case ionosplleric parameler s~ale would be omilled Çrom llle Kalmall l~iller slates. Similarly, tlle switchin~ eycle migllt allernlle belweell Ille two fiequencies wi~ lle 15 antemla bein~ always llle same, in WlliCIl ease llle Kallnall rillel proccss cslimalioll Or lllc vellicle headin~, would nol bencrll rrom llle Ineasurenlclll of calriel pllases orsi~nals received al spalially separaled anlellllas. Ilowever, errors in llle ionospllelic paralnelcr coukl slill be eslimalecl ulilizillg lllc Kalmall rlller plocess.
Tl~e prelcrre~ elllbodilllelll sllown in l:i~. I sllows 1 reeeiver proeessor 25, a naviL~ali ~n 20 processor 35, a range processor 31, and a Kalman filler 29. An allerllalive preferled embodillle would utilize a single digilal processor lo perrorm llle runcliolls of lhese l'our processors.
B
INTEGRATED GPS/INERTIAL NAVIGATION APPARATUS
PROVIDING IMPROVED HEADING ESTIMATES
TECHNICAL FIELD
This invention relates generally to methods and apphld~us for lltili7ing satellite signals in 10 combination with an inertial navigation system (INS)to determine vehicle heading. More specifically, the invention relates to the use of signals transmitted by a Global Positioning System (GPS) satellite and lNSs which utilize gyros with bias eITors ranging up to one degree per hour.
BACKGROUND ART
Position, velocity, and attitude of a vehicle can be accurately determined using well-known methods of coupling GPS receiver/processors and INSs. Accurately detenninin~ the he~-ling of a vehicle under all conditions of motion, however, requires either a long period of time for 20 gyrocompassing in the case of medium-accuracy INSs (i.e. gyro bias errors of ~0.01 degrees/hour) or the use of a magnetic detector such as a flux valve in the case of low-accuracy INSs (i.e. gyro bias errors of~ 1 degree/hour).
INS measulelllents of hçading can be corrected by utili7ing GPS measurements of vehicle position and velocit,v when vehicle maneuvering is taking place. However, in the case of a low-25 accuracy INS, errors in hP~-iing during periods without turns or ~cceler~tions grow as a result of gyro drift--potentially one degree for every hour of non-acceleration--or be limited to about one degree by the errors in the flux valve.
Another approach is to use two GPS receivers having a common time reference with two ~ntenn~ to derive the phase differences between GPS carrier phase as received by the ~ntenn~
The phase differences and knowledge of the GPS satellite positions as determined by their ephemerides and time can then be used with INS pitch and roll to determine vehicle heading.
Because of the periodicity of the carrier phase, ambiguities arise and various methods have been devised to resolve them. The need for two receivers entails an undesirable cost penalty, S especially when used with a low-cost INS.
DISCLOSURE OF INVENTION
10 The integrated GPS/inertial navigation apparatus is for use with two spatially-separated antennas on a mobile platform, the two antçnn~ being capable of receiving signals from one or more satellites. Each satellite signal comprises one or more component signals with each component signal having a different carrier frequency. The integrated GPS/inertial navigation apparatus consists of a receiver and an inertial navigation system.
15 The receiver measures the carrier phase of each of one or more component signals of one or more satellite signals received by each of the two antennas during successive time periods of duration Tp. Phase measured during a Tp time period is called Tp-phase. Only one component signal of one satellite signal received by one antenna is measured during any single time period.
The receiver utilizes the Tp-phases of each component signal obtained during a Tk time period 20 to estimate the phase of the component signal at the end of the Tk time period, the estimated phase at the end of the Tk time period being called the Tk-phase.
The inertial navigation system, comprising inertial sensors and a digital processor, utilizes the Tk-phases in cletçrmining the h~ling of the vehicle. The inertial navigation system also utili~ the Tk-phases in det~rmining the displacement of each of the t~,vo ~nt~nn~c from the 25 inertial sensors of the inertial navigation system. The measured phase of a component signal is subject to error as a result of the satellite signal traversing the ionosphere. The inertial navigation system achieves more accurate estim~t~?s of heading and antenna displ~cçment~ by utili7ing the Tk-phases in determining the ionospheric corrections.
~ 7 59~5 .,~
BRIEF DESCRIPI ION OF DRAWINGS
FIG. I is a block diagram of the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The preferred embodiment of the invention is shown in Fig. 1 and consists of two antennas 1 and 3, a switched-channel GPS receiver 5 and an inertial navigation system (INS) 7. The two 10 spatially-separated omnidirectional ~nt~nn~c 1 and 3 are designed to receive the GPS navigation signals l~ lilled by the GPS satellites at frequencies Ll (IS75.42 MHz) and L2 (1227.6 MHz).
The antennas are mounted on a platform in such a way that the projections of the phase centers of the two antennas onto a nominally level plane are at least one meter apart. This separation could be achieved on an aircraft, for example, by either mounting the antennas along 15 the top of the fuselage or on one or both of the wings. On a land or sea vehicle, any part of the structure could be used as long as the one-meter separation of the projection of the antenna locations to a nominally horizontal plane is provided with a reasonably unobstructed view of the sky. The antennas need not physically be in a nominally horizontal plane, however. One may be higher than the other.
20 The antennas should be attached to ground planes to m~int~in good control of the phase centers of the antennas at all viewing angles to the satellites. Reflections received from other parts of the vehicle should also be minimi7.o~1 for optimum performance.
The navigation signals received by ~nt~nn~ I feed into RF channels 9 and 11, and those received by ~ntt nn~ 3 feed into RF channels 13 and 15 . RF channels 9 and 13 pass only the L 1 25 signal colnpollel~t while RF r l~nn~!s 1 1 and 15 pass only the L2 signal component. The outputs of the four RF channels feed into the switch 17.
The single output of the switch 17 feeds into a down-converter 19 which tr~n~!~tes the frequency of the input signal, under the control signal appearing on conductor 21, to a fixed IF.
The output of the down converter 19 feeds into the signal digitizer 23.
30 The signal digitizer 23 samples in-phase and quadrature components of the input signal at twice 2 1 7 5'~45 the code chipping rate and supplies these in-phase and quadrature digitized samples to the receiver processor 25 which performs a number of functions among which is the estimation of carrier phase.
The down-converter 19, the signal digitizer 23, and the receiver processor 25 (insofar as the 5 basic functions required for deriving navigation information, including the estimation of pseudorange, delta pseudorange, and carrier phase) are described in greater detail in U.S. Patent No. 4,807,256.
The receiver processor 25, by means of a control signal on line 27, causes the switch 17 to periodically and repetitively sequence its four input signals to its output thereby obtaining 10 pseudorange, delta pseudorange, and carrier phase for the four combinations of Antçnn~ and frequency during each repetition cycle. Pseudorange Rp is defined by the equation R = R + c(~t- ~T) + /~R jon + ~RtroP (1) where R is the actual range from the antenna to the satellite, c is the propagation speed of the radio waves in vacuum, ~t is the satellite clock error, ~T is the user clock error, ~Rjon and ~Rtrop are ionospheric and tropospheric corrections which account for the difference in propagation speed of radio waves through the ionosphere and troposphere respectively as 20 compared to a vacuum.
Delta pseudorange is the change in pseudorange over a specified time interval and is equal to the time rate of change of actual range adjusted for the difference in satellite clock rate error and user clock rate error and is equivalent to the measured Doppler shift in the carrier frequency of the received satellite signal.
25 Carrier phase ~ is defined by the equation (2) ~ = R + c(~t-~T) - N~ + /\Rion + ~Rtrop 30 where ~ is the radio-wave wavelength and N is an integer such that ~ is constrained to a one-21 759~
'~_ wavelength range.
The Kalman filter 29 located in the inertial navigation system 7 supplies to the receiver processor 25 computed user clock error and user clock rate error. The receiver processor 25 adds the computed user clock error to its estimates of pseudorange and carrier phase and adds the 5 computed user clock rate error to its estimates of delta pseudorange to obtain user clock adjusted (UCA) estimates. These UCA pseudoranges, delta pseudoranges, and carrier phases are supplied by the receiver processor 25 to the Kalman filter 29.
The receiver processor 25 extracts satellite ephemeris data, satellite clock and clock rate errors, and synchronization data from the satellite signals and supplies this data to range 10 processor 31 in the inertial navigation system 7.
The inertial measurement unit (IMU) 33, a Litton LN-200 model, supplies to navigation processor 35 in the inertial navigation system 7 platform acceleration measured by accelerometers fixed to the platform and platform angular rotation rate measured by gyros also fixed to the platform. This data is corrected by the navigation processor 35 for accelerometer and 15 gyro bias, scale factor error, and mi~lignment using data supplied by the Kalman filter 29.
A barometric altimeter 37 provides a platform altitude input to navigation processor 35.
Corrections for altimeter bias and scale factor errors are supplied to the navigation processor 35 by the Kalman filter 29.
The navigation processor 35 uses the platform acceleration, angular rotation rate, and altitude 20 to periodically compute the position, velocity, and attitude of the platform. These quantities are corrected with data supplied by the Kalman filter 29, and the corrected data is passed on to the range processor 31.
The range processor 31 uses this corrected data together with ~nt~nn~ displacements (corrected in accordance with the ~ntPnn~ displacement errors supplied by the Kalman filter 29) 25 and the satellite ephemeris data to obtain computed ranges, delta ranges, and carrier phases. The range processor 31 adds the satellite clock error, the ionospheric correction, and the tropospheric correction to each computed range thereby obtaining a quantity analogous to the UCA
pseudorange supplied to the Kalman filter 29 by the receiver processor 25.
The ionospheric correction is det~rmined from an equation involving an ionospheric 30 parameter (the error in the ionospheric parameter being determined by the Kalman filter 29 and supplied to the range processor). The tropospheric correction is computed by the range processor ~ ~ 7~45 31 rrom the epllemcris data and tlle location of the user's vehicle.
The range processor 31 also adds satellite clock rate error to each computed delta range thereby obtaining a quantity analogous to the UCA delta pseudorange supplied by the receiver processor 25 to the Kalman filter 29. The range processor 31 also subtracts Nl from each UCA
5 pseudorange analog to obtain a quantity analogous to UCA carrier phase. These computed UCA
pseudorange analogs, computed UCA delta range analogs, and computed UCA carrier phase analogs are supplied to the Kalman filter 29.
The determination of N can be accomplished in any one of a number of ways. Examples are given by Knight in U.S. Pat. No. 5,296,861, by Ward et al. in U.S. Pat. No. 5,185,610, and by 10 Hatch in U.S. Pat. No. 5,072,227.
The Kalman filter 29 obtains a minim~l mean-square-error solution of the navigation problem and supplies corrections to the input data in anticipation of the next iteration of the Kalman process. The Kalman process is well-known and will not be described here since it is described in detail in a number of textbooks, one example being A. Gelb, ed., Applied Optimal l~slin7ation, 15 The Analytical Sciences Corporation, The M.l.T. Press, Cambridge, Mass., 1974.
Tlle vehicle states used by the Kalman filter 29 number 42 and consist of two level position states, one heading state, three velocity states, three attitude states, one altitude state, three accelerometer bias states, three accelerometer scale factor states, six accelerometer misalignment states, tllree gyro bias states, tllree gyro scale factor states, tllree gyro misalignment states, one 20 barometric altimeter bias state, one barometric altimeter scale factor state, one user clock phase statc, one user clock fi equency state, one iollosplleric parameter state, and six antelllla displacement states.
The time Tk typically required to execute a Kalman filter iteration is several seconds. The switching cycle for the switch 17 in Fig. 1 may be as long 4Tk, in which case the receiver 25 processor 25 provides an estimate of the carrier phase for one frequency and one antenna coincident with the beginning of a Kalman filter iteration. The receiver processor 25 may produce carrier phase estimates at Tp intervals where Tp may be as short as a millisecond, in which case the carrier phase estimate for a particular frequency and for a particular antenna produced at the beginning of each Tk, interval would be calculated using all of the carrier phase 30 estimates for the particular frequency and for the particular frequency and for the particular antenna obtained during the prior Tk interval. However, only one new carrier phase estimate for each frequency and for each antenna would enter the Kalman filter process during each 2 4~ 7 ~
, ....
iteration. Tlle yroccdurc for dclern~ining thc phasc at the end of a time period usin~ pllase measurements obtained during ~he time illlerval is a strai~lltforward and well-understoo(l slalislieal proce(3ule and is described ill many lexlbooks.
Ihe swilcl~ cycle l'or llle swilcll 17 nlay be as sllorl as 41~" in wllicll casc Ille rceeivcl 5 proecssor 25 woukl provide four carrier pllase estilllales al lhe be~imlillL~ of cacll J k illlerva~ le receiver processor 25 would calculate lllc earrier pll.lse eslinlale lor a parlicular ~'reqllcllcy alld a particular anle~ a delivered at llle begilmitlg of a Tk inlerval using all ol tl~e pllase estilllales corrcspondillg lo lllc salnc rrcqucncy and llle salnc anlclllla oblaincd dulillg lllc pliOI' 'I'k illlclval.
The switclling eycle can of course ran~,e anywllere belween 4T~, and 41 k.
10 Tlle preferred embodilllenl is a syslem in whicll llle swilehill~ cycle results ill llle seleclio Or si~,nals of rrequency L I an(l L2 from eaeh of lhe lwo anlemlas. ln allo(ller enlbodilllelll, llle s~ cl~ , cyclc woul~J cyclc l)ClWCCIl lwo .ullcllllas wi~ llc Si~ll.ll Iic~lucllcy .IIW.lyS l)~ , cil~
L l or L2, in whicll case ionosplleric parameler s~ale would be omilled Çrom llle Kalmall l~iller slates. Similarly, tlle switchin~ eycle migllt allernlle belweell Ille two fiequencies wi~ lle 15 antemla bein~ always llle same, in WlliCIl ease llle Kallnall rillel proccss cslimalioll Or lllc vellicle headin~, would nol bencrll rrom llle Ineasurenlclll of calriel pllases orsi~nals received al spalially separaled anlellllas. Ilowever, errors in llle ionospllelic paralnelcr coukl slill be eslimalecl ulilizillg lllc Kalmall rlller plocess.
Tl~e prelcrre~ elllbodilllelll sllown in l:i~. I sllows 1 reeeiver proeessor 25, a naviL~ali ~n 20 processor 35, a range processor 31, and a Kalman filler 29. An allerllalive preferled embodillle would utilize a single digilal processor lo perrorm llle runcliolls of lhese l'our processors.
B
Claims (10)
1. Apparatus for use with two antennas on a mobile platform, the two antennas being capable of receiving signals from one or more satellites, each satellite signal comprising one or more component signals, each component signal having a different carrier frequency, the apparatus comprising:
a receiver which obtains satellite ephemeris data and measures the carrier phase of each of one or more component signals of one or more satellite signals received from one or more satellites by each of the two antennas during successive time periods of duration T p, phase measured during a T p time period being called T p-phase, only one component signal of one satellite signal received by one antenna being measured during any single T p time period, the receiver utilizing the T p-phases of each component signal obtained during a T k time period by each antenna to estimate the phase of the component signal at the end of the T k time period, the estimated phase at the end of the T k time period being called the T k-phase, T k being equal to or greater than T p;
an inertial navigation system comprising inertial sensors and a digital processor, the inertial navigation system utilizing measurements of platform acceleration and platform angular rotation rate in determining the positions of the two antennas and the heading of the platform, the inertial navigation system utilizing the satellite ephemeris data and the positions of the two antennas to obtain computed ranges from the two antennas to the satellites, the inertial navigation system utilizing the computed ranges and the T k-phases in determining the error in the heading of the vehicle.
a receiver which obtains satellite ephemeris data and measures the carrier phase of each of one or more component signals of one or more satellite signals received from one or more satellites by each of the two antennas during successive time periods of duration T p, phase measured during a T p time period being called T p-phase, only one component signal of one satellite signal received by one antenna being measured during any single T p time period, the receiver utilizing the T p-phases of each component signal obtained during a T k time period by each antenna to estimate the phase of the component signal at the end of the T k time period, the estimated phase at the end of the T k time period being called the T k-phase, T k being equal to or greater than T p;
an inertial navigation system comprising inertial sensors and a digital processor, the inertial navigation system utilizing measurements of platform acceleration and platform angular rotation rate in determining the positions of the two antennas and the heading of the platform, the inertial navigation system utilizing the satellite ephemeris data and the positions of the two antennas to obtain computed ranges from the two antennas to the satellites, the inertial navigation system utilizing the computed ranges and the T k-phases in determining the error in the heading of the vehicle.
2. The apparatus of claim 1 wherein the nominal displacements of the two antennas from the inertial sensors are predetermined, the inertial navigation system utilizing the T k-phases in determining the error in the displacement of each of the two antennas from the inertial sensors of the inertial navigation system.
3. The apparatus of claim 1 wherein the inertial navigation system utilizes the T k-phases in determining the ionospheric corrections.
4. The apparatus of claim 1 wherein the inertial navigation system obtains estimates of navigation quantities including heading by utilizing a Kalman filter process, the time when new T k-phases become available coinciding with the beginning of a Kalman filter iteration.
5. The apparatus of claim 1 wherein the inertial navigation system obtains estimates of navigation quantities including heading by utilizing a Kalman filter process, the new T k-phases becoming available with the beginning of each Kalman filter iteration.
6. The apparatus of claim 1 wherein, the inertial navigation system obtains estimates of navigation quantities including heading by utilizing a Kalman filter process, one new T k-phase becoming available with the beginning of each Kalman filter iteration.
7. The apparatus of claim 1 wherein the receiver comprises:
a component signal selector having a plurality of input ports, an output port, and a control input port, at least one of the input ports being connected to one antenna, the other input ports being connected to the other antenna, a control signal at the control input port causing the input ports to be successively connected to the output port for time periods T p, the signal component selector causing a signal component of the signal entering the input port connected to the output port to be translated in frequency from an RF to an IF;
a processor having a signal input port, a control output port, and a data output port, the signal input port being connected to the output port of the signal component selector, the control output port being connected to the control input port of the component signal selector, the control signal being supplied to the component signal selector by the processor through the control output port, the data output port being connected to the inertial navigation system, the processor measuring the T p-phase of the component signal entering the input port during each T p time period and computing the T k-phase for each component signal entering the input port during each T k time period, the T k-phases being supplied to the inertial navigation system through the data output port.
a component signal selector having a plurality of input ports, an output port, and a control input port, at least one of the input ports being connected to one antenna, the other input ports being connected to the other antenna, a control signal at the control input port causing the input ports to be successively connected to the output port for time periods T p, the signal component selector causing a signal component of the signal entering the input port connected to the output port to be translated in frequency from an RF to an IF;
a processor having a signal input port, a control output port, and a data output port, the signal input port being connected to the output port of the signal component selector, the control output port being connected to the control input port of the component signal selector, the control signal being supplied to the component signal selector by the processor through the control output port, the data output port being connected to the inertial navigation system, the processor measuring the T p-phase of the component signal entering the input port during each T p time period and computing the T k-phase for each component signal entering the input port during each T k time period, the T k-phases being supplied to the inertial navigation system through the data output port.
8. A method for determining the heading of a vehicle utilizing inertial sensors and at least one satellite signal, each satellite signal comprising one or more component signals, each component signal having a different carrier frequency, the method comprising the steps:
(a) obtaining satellite ephemeris data and measuring during successive time periods of duration T p the phase of each of one or more component signals of one or more satellite signals received from one or more satellites at first and second predetermined points on the vehicle, the phase of only one component signal being measured during any T p time period, a phase measured during a T p time period being called a T p-phase;
(b) computing the phase of each component signal of each satellite signal received at each of the first and second predetermined points at the end of a T k time period utilizing the T p-phases for that component signal measured during the T k time period, the computed phase of a component signal at the end of a T k time period being called a T k-phase;
(c) utilizing measurements of platform acceleration and platform angular rotation rate referenced to a third predetermined point on the vehicle in determining the positions of the first and second predetermined points and the heading of the vehicle and then utilizing satellite ephemeris data and the positions of the first and second predetermined points to compute ranges from the first and second predetermined points to the one or more satellites at the end of a T k time period;
(d) determining the error in vehicle heading at the end of a T k time period utilizing the measurements and computations made in steps (a), (b), and (c);
(e) repeating steps (a), (b), (c), and (d) indefinitely.
(a) obtaining satellite ephemeris data and measuring during successive time periods of duration T p the phase of each of one or more component signals of one or more satellite signals received from one or more satellites at first and second predetermined points on the vehicle, the phase of only one component signal being measured during any T p time period, a phase measured during a T p time period being called a T p-phase;
(b) computing the phase of each component signal of each satellite signal received at each of the first and second predetermined points at the end of a T k time period utilizing the T p-phases for that component signal measured during the T k time period, the computed phase of a component signal at the end of a T k time period being called a T k-phase;
(c) utilizing measurements of platform acceleration and platform angular rotation rate referenced to a third predetermined point on the vehicle in determining the positions of the first and second predetermined points and the heading of the vehicle and then utilizing satellite ephemeris data and the positions of the first and second predetermined points to compute ranges from the first and second predetermined points to the one or more satellites at the end of a T k time period;
(d) determining the error in vehicle heading at the end of a T k time period utilizing the measurements and computations made in steps (a), (b), and (c);
(e) repeating steps (a), (b), (c), and (d) indefinitely.
9. The method of claim 8 wherein the nominal displacements of the first and second predetermined points from the third predetermined point are predetermined, the method further comprising the step:
(f) determining the errors in the displacements of the first and second predetermined points from the third predetermined point at the end of a T k time period utilizing the measurements and computations made in steps (a), (b), and (c), step (f) being performed at the same time as step (d).
(f) determining the errors in the displacements of the first and second predetermined points from the third predetermined point at the end of a T k time period utilizing the measurements and computations made in steps (a), (b), and (c), step (f) being performed at the same time as step (d).
10. The method of claim 8 further comprising the step:
(g) determining the ionospheric corrections to the phases at the end of the T k time period utilizing measurements, computations, and determinations made in steps (a), (b), and (c), the step (g) being performed at the same time as step (d).
(g) determining the ionospheric corrections to the phases at the end of the T k time period utilizing measurements, computations, and determinations made in steps (a), (b), and (c), the step (g) being performed at the same time as step (d).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/511965 | 1995-08-07 | ||
| US08/511,965 US5657025A (en) | 1995-08-07 | 1995-08-07 | Integrated GPS/inertial navigation apparatus providing improved heading estimates |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2175945A1 CA2175945A1 (en) | 1997-02-08 |
| CA2175945C true CA2175945C (en) | 1998-12-22 |
Family
ID=24037146
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002175945A Expired - Fee Related CA2175945C (en) | 1995-08-07 | 1996-05-07 | Integrated gps/inertial navigation apparatus providing improved heading estimates |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5657025A (en) |
| EP (1) | EP0763749A1 (en) |
| JP (1) | JPH09178508A (en) |
| KR (1) | KR970012260A (en) |
| CA (1) | CA2175945C (en) |
| IL (1) | IL118144A (en) |
Families Citing this family (98)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5928309A (en) * | 1996-02-05 | 1999-07-27 | Korver; Kelvin | Navigation/guidance system for a land-based vehicle |
| US6236365B1 (en) | 1996-09-09 | 2001-05-22 | Tracbeam, Llc | Location of a mobile station using a plurality of commercial wireless infrastructures |
| US9134398B2 (en) | 1996-09-09 | 2015-09-15 | Tracbeam Llc | Wireless location using network centric location estimators |
| US7764231B1 (en) | 1996-09-09 | 2010-07-27 | Tracbeam Llc | Wireless location using multiple mobile station location techniques |
| US5923286A (en) * | 1996-10-23 | 1999-07-13 | Honeywell Inc. | GPS/IRS global position determination method and apparatus with integrity loss provisions |
| US5853143A (en) * | 1996-12-23 | 1998-12-29 | Boeing North American, Inc. | Airbreathing propulsion assisted flight vehicle |
| US5757316A (en) * | 1997-02-01 | 1998-05-26 | Litton Systems, Inc. | Attitude determination utilizing an inertial measurement unit and a plurality of satellite transmitters |
| US5986547A (en) | 1997-03-03 | 1999-11-16 | Korver; Kelvin | Apparatus and method for improving the safety of railroad systems |
| US5877723A (en) * | 1997-03-05 | 1999-03-02 | Caterpillar Inc. | System and method for determining an operating point |
| US5906655A (en) * | 1997-04-02 | 1999-05-25 | Caterpillar Inc. | Method for monitoring integrity of an integrated GPS and INU system |
| US5983160A (en) * | 1997-04-21 | 1999-11-09 | Raytheon Company | Increase jamming immunity by optimizing processing gain for GPS/INS systems |
| EP1793240A1 (en) * | 1997-04-21 | 2007-06-06 | Raytheon Company | Increased jamming immunity by optimizing processing gain for GPS/INS systems |
| US5917448A (en) * | 1997-08-07 | 1999-06-29 | Rockwell Science Center, Inc. | Attitude determination system with sequencing antenna inputs |
| US6094163A (en) * | 1998-01-21 | 2000-07-25 | Min-I James Chang | Ins alignment method using a doppler sensor and a GPS/HVINS |
| US6266584B1 (en) * | 1998-03-31 | 2001-07-24 | Space Systems/Loral, Inc. | Robust autonomous GPS time reference for space application |
| US6234799B1 (en) * | 1998-04-06 | 2001-05-22 | American Gnc Corporation | Real-time IMU simulator |
| US6167347A (en) * | 1998-11-04 | 2000-12-26 | Lin; Ching-Fang | Vehicle positioning method and system thereof |
| US6157891A (en) * | 1998-11-16 | 2000-12-05 | Lin; Ching-Fang | Positioning and ground proximity warning method and system thereof for vehicle |
| US6178363B1 (en) | 1998-12-22 | 2001-01-23 | The Boeing Company | Inertially augmented GPS landing system |
| GB9906781D0 (en) | 1999-03-24 | 1999-05-19 | British Aerospace | Height estimating apparatus |
| US6697752B1 (en) | 2000-05-19 | 2004-02-24 | K&L Technologies, Inc. | System, apparatus and method for testing navigation or guidance equipment |
| GB2368218B (en) | 2000-06-01 | 2004-04-28 | Furuno Electric Co | System for determining the heading and/or attitude of a body |
| US10641861B2 (en) | 2000-06-02 | 2020-05-05 | Dennis J. Dupray | Services and applications for a communications network |
| US9875492B2 (en) | 2001-05-22 | 2018-01-23 | Dennis J. Dupray | Real estate transaction system |
| US10684350B2 (en) | 2000-06-02 | 2020-06-16 | Tracbeam Llc | Services and applications for a communications network |
| US8060389B2 (en) | 2000-06-07 | 2011-11-15 | Apple Inc. | System and method for anonymous location based services |
| US6456234B1 (en) | 2000-06-07 | 2002-09-24 | William J. Johnson | System and method for proactive content delivery by situation location |
| US8489669B2 (en) | 2000-06-07 | 2013-07-16 | Apple Inc. | Mobile data processing system moving interest radius |
| FI108372B (en) | 2000-06-30 | 2002-01-15 | Nokia Corp | Method and apparatus for position measurement |
| US6496778B1 (en) * | 2000-09-14 | 2002-12-17 | American Gnc Corporation | Real-time integrated vehicle positioning method and system with differential GPS |
| GB2367199B (en) * | 2000-09-20 | 2005-01-26 | Parthus | Apparatus for receiving ranging signals |
| US6622090B2 (en) * | 2000-09-26 | 2003-09-16 | American Gnc Corporation | Enhanced inertial measurement unit/global positioning system mapping and navigation process |
| WO2002039138A1 (en) * | 2000-11-06 | 2002-05-16 | Lin Ching Fang | Positioning and ground proximity warning method and system thereof for vehicle |
| JP4695778B2 (en) * | 2001-06-11 | 2011-06-08 | 古野電気株式会社 | Deviation measuring device and course maintenance supporting device |
| US6654685B2 (en) | 2002-01-04 | 2003-11-25 | The Boeing Company | Apparatus and method for navigation of an aircraft |
| US6671587B2 (en) | 2002-02-05 | 2003-12-30 | Ford Motor Company | Vehicle dynamics measuring apparatus and method using multiple GPS antennas |
| US6859727B2 (en) * | 2003-01-08 | 2005-02-22 | Honeywell International, Inc. | Attitude change kalman filter measurement apparatus and method |
| US6789014B1 (en) | 2003-05-09 | 2004-09-07 | Deere & Company | Direct modification of DGPS information with inertial measurement data |
| US6694260B1 (en) | 2003-05-09 | 2004-02-17 | Deere & Company | Inertial augmentation for GPS navigation on ground vehicles |
| US7268727B2 (en) * | 2004-04-30 | 2007-09-11 | Paul Yalden Montgomery | Method and apparatus for improved position, velocity, orientation or angular rate sensor |
| KR101168100B1 (en) * | 2004-06-02 | 2012-07-24 | 록웰 콜린스 컨트롤 테크놀로지스, 인코포레이티드 | Systems and methods for estimating position, attitude and/or heading of a vehicle |
| US7317977B2 (en) * | 2004-08-23 | 2008-01-08 | Topcon Positioning Systems, Inc. | Dynamic stabilization and control of an earthmoving machine |
| US20060071849A1 (en) * | 2004-09-30 | 2006-04-06 | Lockheed Martin Corporation | Tactical all weather precision guidance and navigation system |
| US8954251B2 (en) | 2004-10-05 | 2015-02-10 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| US7239953B2 (en) * | 2004-10-05 | 2007-07-03 | Vision Works, Llc | Absolute acceleration sensor for use within moving vehicles |
| US9327726B2 (en) | 2004-10-05 | 2016-05-03 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| US8437935B2 (en) | 2004-10-05 | 2013-05-07 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| US9878693B2 (en) | 2004-10-05 | 2018-01-30 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| WO2006071197A1 (en) * | 2004-12-30 | 2006-07-06 | Agency For Science, Technology And Research | Fully integrated ultra wideband transmitter circuits and systems |
| US20060287824A1 (en) * | 2005-01-29 | 2006-12-21 | American Gnc Corporation | Interruption free navigator |
| US7353034B2 (en) | 2005-04-04 | 2008-04-01 | X One, Inc. | Location sharing and tracking using mobile phones or other wireless devices |
| US7415354B2 (en) * | 2006-04-28 | 2008-08-19 | L-3 Communications Corporation | System and method for GPS acquisition using advanced tight coupling |
| US7739045B2 (en) * | 2006-05-31 | 2010-06-15 | Honeywell International Inc. | Rapid self-alignment of a strapdown inertial system through real-time reprocessing |
| US20080160992A1 (en) * | 2006-06-30 | 2008-07-03 | Qualcomm Incorporated | Handset transmit antenna diversity in mobile satellite systems |
| JP4983132B2 (en) * | 2006-07-26 | 2012-07-25 | 株式会社デンソー | Vehicle direction identification method and vehicle direction identification device. |
| US7668629B2 (en) * | 2006-12-05 | 2010-02-23 | The Boeing Company | Ultra-tightly coupled global navigation satellite system space borne receiver system |
| US8204684B2 (en) | 2007-06-28 | 2012-06-19 | Apple Inc. | Adaptive mobile device navigation |
| US8290513B2 (en) | 2007-06-28 | 2012-10-16 | Apple Inc. | Location-based services |
| US8385946B2 (en) | 2007-06-28 | 2013-02-26 | Apple Inc. | Disfavored route progressions or locations |
| US8175802B2 (en) | 2007-06-28 | 2012-05-08 | Apple Inc. | Adaptive route guidance based on preferences |
| US8108144B2 (en) | 2007-06-28 | 2012-01-31 | Apple Inc. | Location based tracking |
| US9109904B2 (en) | 2007-06-28 | 2015-08-18 | Apple Inc. | Integration of map services and user applications in a mobile device |
| US8774825B2 (en) | 2007-06-28 | 2014-07-08 | Apple Inc. | Integration of map services with user applications in a mobile device |
| US8180379B2 (en) | 2007-06-28 | 2012-05-15 | Apple Inc. | Synchronizing mobile and vehicle devices |
| US8275352B2 (en) | 2007-06-28 | 2012-09-25 | Apple Inc. | Location-based emergency information |
| US9066199B2 (en) | 2007-06-28 | 2015-06-23 | Apple Inc. | Location-aware mobile device |
| US8332402B2 (en) | 2007-06-28 | 2012-12-11 | Apple Inc. | Location based media items |
| US8762056B2 (en) | 2007-06-28 | 2014-06-24 | Apple Inc. | Route reference |
| US8311526B2 (en) | 2007-06-28 | 2012-11-13 | Apple Inc. | Location-based categorical information services |
| US8145391B2 (en) * | 2007-09-12 | 2012-03-27 | Topcon Positioning Systems, Inc. | Automatic blade control system with integrated global navigation satellite system and inertial sensors |
| US8355862B2 (en) | 2008-01-06 | 2013-01-15 | Apple Inc. | Graphical user interface for presenting location information |
| US9250092B2 (en) | 2008-05-12 | 2016-02-02 | Apple Inc. | Map service with network-based query for search |
| US8644843B2 (en) | 2008-05-16 | 2014-02-04 | Apple Inc. | Location determination |
| US20090312036A1 (en) | 2008-06-16 | 2009-12-17 | Skyhook Wireless, Inc. | Methods and systems for improving the accuracy of expected error estimation in location determinations using a hybrid cellular and wlan positioning system |
| US8369867B2 (en) | 2008-06-30 | 2013-02-05 | Apple Inc. | Location sharing |
| US8359643B2 (en) | 2008-09-18 | 2013-01-22 | Apple Inc. | Group formation using anonymous broadcast information |
| US8260320B2 (en) | 2008-11-13 | 2012-09-04 | Apple Inc. | Location specific content |
| US8169366B2 (en) * | 2008-11-25 | 2012-05-01 | Qualcomm Incorporated | Reconfigurable satellite positioning system receivers |
| US8306726B2 (en) * | 2009-04-28 | 2012-11-06 | Caterpillar Inc. | Position monitoring system for a mobile machine |
| US8660530B2 (en) | 2009-05-01 | 2014-02-25 | Apple Inc. | Remotely receiving and communicating commands to a mobile device for execution by the mobile device |
| US8666367B2 (en) | 2009-05-01 | 2014-03-04 | Apple Inc. | Remotely locating and commanding a mobile device |
| US8670748B2 (en) | 2009-05-01 | 2014-03-11 | Apple Inc. | Remotely locating and commanding a mobile device |
| US9538493B2 (en) | 2010-08-23 | 2017-01-03 | Finetrak, Llc | Locating a mobile station and applications therefor |
| GB201016251D0 (en) | 2010-09-28 | 2010-11-10 | Omnisense Ltd | Positioning system |
| US9803983B2 (en) | 2010-12-03 | 2017-10-31 | Qualcomm Incorporated | Inertial sensor aided heading and positioning for GNSS vehicle navigation |
| US9116233B2 (en) * | 2012-07-10 | 2015-08-25 | Broadcom Corporation | Power mode control for sensors |
| US8914196B1 (en) | 2013-11-01 | 2014-12-16 | Automotive Technologies International, Inc. | Crash sensor systems utilizing vehicular inertial properties |
| US20140224009A1 (en) * | 2013-02-13 | 2014-08-14 | Hdt Expeditionary Systems | High velocity wind sonde |
| US9855986B2 (en) | 2013-08-28 | 2018-01-02 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| US9371002B2 (en) | 2013-08-28 | 2016-06-21 | Vision Works Ip Corporation | Absolute acceleration sensor for use within moving vehicles |
| US9528834B2 (en) | 2013-11-01 | 2016-12-27 | Intelligent Technologies International, Inc. | Mapping techniques using probe vehicles |
| RU2573119C2 (en) * | 2014-05-27 | 2016-01-20 | Открытое Акционерное Общество "Центральное Конструкторское Бюро "Нептун" | Method and system to generate parameters of angular orientation of hull |
| US10197681B2 (en) * | 2014-12-26 | 2019-02-05 | Furuno Electric Co., Ltd. | State calculating device, method of calculating state, and state calculating program |
| CN104913790B (en) * | 2015-05-28 | 2017-11-28 | 北京航天控制仪器研究所 | A kind of inertial navigation system heading effect error closed loop compensation method applied to communication in moving |
| US10094930B2 (en) * | 2015-06-23 | 2018-10-09 | Honeywell International Inc. | Global navigation satellite system (GNSS) spoofing detection with carrier phase and inertial sensors |
| RU2599285C1 (en) * | 2015-07-02 | 2016-10-10 | Акционерное общество "ЗАСЛОН" | Method and system of ship devices angular orientation determining taking into account of its hull deformations |
| CN113474680A (en) * | 2019-02-25 | 2021-10-01 | 古野电气株式会社 | Mobile information calculation device and mobile information calculation method |
| US11650333B2 (en) | 2021-09-07 | 2023-05-16 | Honeywell International Inc. | Methods and apparatuses for automatic object heading determinations |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4809005A (en) * | 1982-03-01 | 1989-02-28 | Western Atlas International, Inc. | Multi-antenna gas receiver for seismic survey vessels |
| US4754280A (en) * | 1982-09-10 | 1988-06-28 | The Charles Stark Draper Laboratory, Inc. | Attitude sensing system |
| US4807256A (en) | 1985-12-23 | 1989-02-21 | Texas Instruments Incorporated | Global position system receiver |
| US5075695A (en) * | 1987-10-08 | 1991-12-24 | Baghdady Elie J | Method and apparatus for signal modulation and detection |
| US5072227A (en) | 1989-09-26 | 1991-12-10 | Magnavox Government And Industrial Electronics Company | Method and apparatus for precision attitude determination |
| US5177489A (en) * | 1989-09-26 | 1993-01-05 | Magnavox Electronic Systems Company | Pseudolite-aided method for precision kinematic positioning |
| US5185610A (en) | 1990-08-20 | 1993-02-09 | Texas Instruments Incorporated | GPS system and method for deriving pointing or attitude from a single GPS receiver |
| US5347286A (en) * | 1992-02-13 | 1994-09-13 | Trimble Navigation Limited | Automatic antenna pointing system based on global positioning system (GPS) attitude information |
| US5268695A (en) * | 1992-10-06 | 1993-12-07 | Trimble Navigation Limited | Differential phase measurement through antenna multiplexing |
| US5296861A (en) | 1992-11-13 | 1994-03-22 | Trimble Navigation Limited | Method and apparatus for maximum likelihood estimation direct integer search in differential carrier phase attitude determination systems |
-
1995
- 1995-08-07 US US08/511,965 patent/US5657025A/en not_active Expired - Lifetime
-
1996
- 1996-05-03 IL IL11814496A patent/IL118144A/en not_active IP Right Cessation
- 1996-05-07 CA CA002175945A patent/CA2175945C/en not_active Expired - Fee Related
- 1996-06-26 JP JP8165741A patent/JPH09178508A/en active Pending
- 1996-07-22 EP EP96111776A patent/EP0763749A1/en not_active Withdrawn
- 1996-07-30 KR KR1019960031433A patent/KR970012260A/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| KR970012260A (en) | 1997-03-29 |
| IL118144A (en) | 1998-08-16 |
| JPH09178508A (en) | 1997-07-11 |
| IL118144A0 (en) | 1996-09-12 |
| EP0763749A1 (en) | 1997-03-19 |
| US5657025A (en) | 1997-08-12 |
| CA2175945A1 (en) | 1997-02-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2175945C (en) | Integrated gps/inertial navigation apparatus providing improved heading estimates | |
| US7248964B2 (en) | System and method for using multiple aiding sensors in a deeply integrated navigation system | |
| US7171303B1 (en) | Navigation method and apparatus | |
| US6191731B1 (en) | GPS receiver having a fast time to first fix | |
| US6697736B2 (en) | Positioning and navigation method and system thereof | |
| US6246960B1 (en) | Enhanced integrated positioning method and system thereof for vehicle | |
| US6205400B1 (en) | Vehicle positioning and data integrating method and system thereof | |
| US5543804A (en) | Navagation apparatus with improved attitude determination | |
| US4881080A (en) | Apparatus for and a method of determining compass headings | |
| US6055477A (en) | Use of an altitude sensor to augment availability of GPS location fixes | |
| US7409290B2 (en) | Positioning and navigation method and system thereof | |
| US7292185B2 (en) | Attitude determination exploiting geometry constraints | |
| US5757316A (en) | Attitude determination utilizing an inertial measurement unit and a plurality of satellite transmitters | |
| JP3408600B2 (en) | Position calculation method in satellite navigation system | |
| US7400956B1 (en) | Satellite position and heading sensor for vehicle steering control | |
| US20110238308A1 (en) | Pedal navigation using leo signals and body-mounted sensors | |
| US20020116125A1 (en) | Positioning & data integrating method and system thereof | |
| CN111854746A (en) | Positioning method of MIMU/CSAC/altimeter auxiliary satellite receiver | |
| US5455592A (en) | Method and apparatus for calibrating an antenna array | |
| US5781151A (en) | Interferometric trajectory reconstruction technique for flight inspection of radio navigation aids | |
| Kocaman et al. | GPS and INS integration with Kalman filtering for direct georeferencing of airborne imagery | |
| US6211821B1 (en) | Apparatus and method for determining pitch and azimuth from satellite signals | |
| US5890090A (en) | Half-dead-reckoning capable GPS navigation receiver | |
| Kuylen et al. | Attitude determination methods used in the polarx2@ multi-antenna gps receiver | |
| Glazer | GPS receiver operation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |