CA2176883C - Railcar location using mutter networks and locomotive transmitter during transit - Google Patents
Railcar location using mutter networks and locomotive transmitter during transit Download PDFInfo
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- CA2176883C CA2176883C CA002176883A CA2176883A CA2176883C CA 2176883 C CA2176883 C CA 2176883C CA 002176883 A CA002176883 A CA 002176883A CA 2176883 A CA2176883 A CA 2176883A CA 2176883 C CA2176883 C CA 2176883C
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- tracking
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L25/00—Recording or indicating positions or identities of vehicles or vehicle trains or setting of track apparatus
- B61L25/02—Indicating or recording positions or identities of vehicles or vehicle trains
- B61L25/021—Measuring and recording of train speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L25/00—Recording or indicating positions or identities of vehicles or vehicle trains or setting of track apparatus
- B61L25/02—Indicating or recording positions or identities of vehicles or vehicle trains
- B61L25/025—Absolute localisation, e.g. providing geodetic coordinates
-
- 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
- G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
- G01S13/82—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein continuous-type signals are transmitted
- G01S13/825—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein continuous-type signals are transmitted with exchange of information between interrogator and responder
-
- 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
- G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
- G01S19/09—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing processing capability normally carried out by the receiver
-
- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G1/00—Traffic control systems for road vehicles
- G08G1/123—Traffic control systems for road vehicles indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, trams
- G08G1/127—Traffic control systems for road vehicles indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, trams to a central station ; Indicators in a central station
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L2205/00—Communication or navigation systems for railway traffic
- B61L2205/04—Satellite based navigation systems, e.g. GPS
-
- 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
- G01S19/34—Power consumption
-
- 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
- G01S2205/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S2205/001—Transmission of position information to remote stations
- G01S2205/002—Transmission of position information to remote stations for traffic control, mobile tracking, guidance, surveillance or anti-collision
-
- 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
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/0009—Transmission of position information to remote stations
- G01S5/0018—Transmission from mobile station to base station
- G01S5/0027—Transmission from mobile station to base station of actual mobile position, i.e. position determined on mobile
Abstract
A method of tracking railcars in transit using global positioning techniques involves determining the location of a railcar by using a Global Positioning System (GPS) receiver and a satellite transceiver on board the locomotive, and a local area network of railcar tracking units. Instead of computing the GPS solution independently and transmitting it to a central station, the railcar tracking units transmit their unique identifications (IDs) to one of the tracking units in the local area network acting as an administrator tracking unit. The administrator tracking unit maintains a list of IDs and periodically transmits the list of IDs to the locomotive. The locomotive locates itself using the GPS system and periodically transmits its position and velocity to the central station.
Description
~D-23,532 2~~68~3 RAILCAR LOCATION USING MUTTER
NETWORKS
AND LOCOMOTIVE TRANSMITTER
DURING TRANSIT
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to asset sacking and, more particularly, to tracking of assets, such as railcars, during transit, using the Global Positioning System (GPS).
Bockgroiutd Description Goods shipped from a manufacturing plant, warehouse or port of entry to a destination are nom~ally tracked to assure their timely and safe delivery. Tracking has heretofore been accomplished in part by use of shipping documents and negotiable instruments, some of which travel with the goods and others of which are transmitted by post or courier to a receiving destination. This paper sacking provides a record which is completed only on the safe delivery and acceptance of the goods. However, there sometimes is a need to know the location of the goods while in transit.
Knowledge of the location of the goods can be used for inventory control, scheduling and monitoring.
Shippers have provided information on the location of goods by tracking their vehicles, knowing what goods are loaded on those vehicles.
Goods are often loaded aboani shipping containers or container trucks, for example, which are in turn loaded aboard railcars. Various devices have been used to track such vehicles. In the case of railcars, passive radio frequency (RF) transponders mounted on the cars have been used to facilitate interrogation of each car as it passes a way station and supply the car's identification (ID). This information is tlxn transmitted by a rndiated -23.532 signal or land line to a central station which tracks the locations of cars.
This technique, however, is deficient in that any traits on a siding cannot pass a way station until it has left the siding, which could involve a considerable delay. Moreover, way station installations are expensive, requiring a compromise that results in way stations being installed at varying distances, depending on the track layout Thus, the precision of location information varies from place to place on the railroad.
Recently, mobile tracking units have been used for tracking various types of vehicles, such as trains. Communication has been provided by means of cellular mobile telephone or RF radio link. Such mobile tracking units are generally installed aboard the locomotive which provides a ready source of power. However, in the case of shipping containers, container truck trailers and railcars, a similar source of power is not readily available.
Mobile tracking units which might be attached to containers and vehicles 13 must be power efficient in order to provide reliable and economical operation.
Most current asset tracking systems are land-based systems wherein a radio unit on the asset transmits information to wayside stations of a fixed network, such as the public land mobile radio network or a cellular network. These networks do not have ubiquitous coverage, and the asset tracking units are expensive. A satellite-based truck sacking system developed by Qualcomm Inc., known as OMNTfRACS, is in operation in the United States and Canada. This system requires a specialized directional antenna and considerable power for operation, while vehicle location, 23 derived from two satellites, is obtained to an accuracy of about one-fourth kilometer. A rail vehicle positioning system described in U.S. Patent No.
5,129,605 to Bums et al. is installed on the locomotive of a train and uses, as inputs to generate a location report, a GPS receiver, a wheel tachometer, transponders, and manual inputs from the locomotive engineer. While the Bums et al. system is accurate for locating a locomotive, it is not adaptable for locating individual railcars in a train. The problem of locating railcars is exacerbated by the fact that railcars in a consist may be removed or added during a particular locomotive's aansit ftrom a starting point to an ultimate destination. Therefore, knowledge of a locomotive's location is not a 33 roliable indication of the location of railcars.
RD-23,532 _3..
In an asset tracking system disclosed in Canadian application Serial No.
2,176,869 filed May 17, 1906 entitled "Local C:'ommunication Network for Power Reduction and Enhanced Reliability in a Multilale Node Tracking System"
by Welles et al. and in C~madian application Set°ial No. 2,176,882 bled May 17, s 1996, entitled "Protocol and Mechanism for Primary and Mutter Mode Communication for Asset Tracking" by Ali et al., assigned to the instant assignee, a tracking system based on a "trzutter" mode local area network is used to generate data which are transmitted to a central station. In this asset tracking system, there are two modes of eomrnunic.ation. Clne mode is to communication between the central station and the tracking units, which is usually via satellite. The second mode is a local area network, referred to as the "mutter" mode, between tracl~ing units. C>ne of the mobile units, denoted the master unit, communicates with the central station. While this asset tracking system is a reliable ar7d accurate system for tracking a ssets during i5 transit, it would be desirable to provide a GP~i receiver and satellite for use of a locomotive in conjunction mobile tracking units on board the railcars and joined in a local area network (LAN).
SUMMARY' OFTHF INVFN'TION
It is therefore an object of the invention to provide a system for ~o global localization of railcars in transit.
Another object of the invention is to provide a method for tracking railcars in transit that does not re,~uire an unlimited power source.
According to the; invention, locatiat~ <nf a railcar is determined using a CJPS receiver and a satellite iransc;eiver on hoard the locomotive and a ?s LAN of railcar tracking units. Instead of conxputing the GPS solution independently and transmitting it to a central station, the railcar tracking units transmit their unique 1Ds to one of the tracking units in the LAN which acts as an administrator unit. 'f he administrator unit, in turn, maintains a list of IDs and periodically transmits the list of LI~s to the locomotive. The 30 locomotive locates itself using the GPS system and periodically transmits its position and velocity to the central station.
More particularly, the I.AN formed by the tracking units on board -23,532 the railcars in a train is leaned a "mutter" network, and selects a master tracking unit which serves as an administrator unit The other tracking units in the network operates as slaves to the selected master unit. The administrator unit of the network communicates with the transceiver of the locomotive. The locomotive contains a GPS location device in conjunction with an on-board transceiver used to communicate with the central station.
The administrator unit transmits to the locomotive transceiver a list of railcar IDs in the LAN. The locomotive transceiver then transmits to the central station, via appropriate medium, the list of railcars along with the location and velocity of the locomotive. On reaching the destination, just before taming itself off, the locomotive transceiver sends to the central station the list of railcar IDs and their current location as calculated by the locomotive GPS receiver.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention believed to be novel are set forth in the appended claims. The invention, however, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings) in which:
Figtue 1 is a block diagram of an exemplary asset tracking system which employs mobile tracking units and operates in accordance with the method of the present invention;
Figure 2 is a block diagram showing in furtiter detail a mobile tracking unit as used in the asset tracking system shown in Figure I;
Figure 3 is a block diagram illusaating organization of the mobile local area network implemented by the present invention;
Figure 4 is a flow diagram showing the steps in operation of the selocted master tracking unit; and Figure 5 is a flow diagram showing the steps in operation of the computer on board the locomotive.
DETAILED DESCRIPTION OF A PREFERRED
EMBODIMENT OF THE INVENTION
~7-23,532 Figure 1, illustrates mobile tracking units which employ navigation signals from a GPS satellite constellation, although, as suggested above, other navigation systems can be used in lieu of GPS. A set of mobile tracking units l0A-lOD are installed in respective railcars 12A-12D, which are to be tracked or monitored. A communication link 14, such as a satellite communication link through a communication satellite 16, is provided between the locomotive and a remote central station 18 manned by one or more operators and having suitable display devices and the like for displaying location and status information for each railcar equipped with a respective mobile tracking unit. Communication link 14 can be conveniently used for transmitting vehicle conditions or events measured with suitable sensing elements. Communication link 14 may be one-way (from the locomotive to the centtal station) or two-way. In a two-way communication link, messages and commands can be sent to the locomotive transceiver, thereby further enhancing reliability of the communication. A constellation of GPS satellites, such as GPS satellites 20A and 20B, provides highly accurate navigation signals which can be used to deterntine vehicle location and velocity when the signals are acquired by a suitable GPS receiver.
Briefly, the GPS was developed by the U.S. Department of Defense and gradually placed into service throughout the 1980s. The GPS satellites constantly transmit radio signals in L-Band frequency using spread spectrum techniques. The transmitted radio signals carry pseudotandom sequences which allow users to determine location on the surface of the earth (within approximately 100 feet), velocity (within about 0.1 MPH), ~d P~~ tire information. GPS is a particularly attractive navigation system to employ, being that the respective orbits of the GPS satellites are chosen so as to provide world-wide coverage and being that such highly-accurate radio signals are provided fret of charge to users by the U.S. federal government.
A locomotive mobile tracking unit, such as shown in Figure 2, includes an on boani navigation set SO capable of generating data substantially corresponding to the locomotive location. Choice of navigation set depends on the particular navigation system used for supplying 3s navigation signals to the mobile tracking unit. Preferably, the navigation set ~D-23,532 2 ~ ~ ~ g g 3 is a GPS receiver such as a multichannel receiver, however, other receivers designed for acquiring signals from a corresponding navigation system may alternatively be employed. For example, depending on the locomotive location accuracy requirements, the navigation set may comprise a Loran-C
receiver or other such less highly-accurate navigation receiver than a GPS
receiver. Further, the navigation set may conveniently comprise a transceiver that inherently provides two-way communication with the central station and avoids the need for separately operating an additional component to implement such two-way communication. Briefly, such transceiver t0 would allow for implementation of satellite range measurement techniques being that the position of the locomotive is simply detemtined at the central station by range measurements to the locomotive and the central station from two satellites whose position in space is known. A key advantage of the present invention is the ability to substantially reduce the total energy required by the mobile tracking units on board a train propelled by the locomotive by utilizing the effectively unlimited power of the locomotive for the GPS navigation set and the transceiver for communicating with the central station.
Mobile tracking unit 10, as shown in Figure Z, includes a suitable electromagnetic transceiver 52, which may comprise a commercially available spread specavm transceiver such as those currently being utilized in wireless LANs. A low profile antenna 54 is coupled to transceiver 52 and navigation sec 50, to serve both. Both transceiver 52 and navigation set 50 are activated by a controller 58 which, in turn, is responsive to signals from a clock module 60. Transceiver 52 is capable of transmitting the vehicle location data by way of communication link 14 (Figure 1) to the central station and receiving commands from the central station by way of the same link. If a GPS receiver is used, the GPS receiver and the transceiver can be conveniently integrated as a single unit for maximizing efficiency of installation and operation. An example of one such integrated unit is the Galaxy lnmarsatGGPS integrated unit, which is available from Trimble Navigation, Sunnyvale, California, and is conveniently designed for data communication and position reporting between the central station and the mobile tracking unit.
A low power, short distance radio link permits joining the nearby RI7-23,532 _7..
mobile tracking units in a network to conserve pc:awer and maintain high reliability and functionality of such network. l:;ach tracking unfit also includes a power source (which comprises a battery pack that can be charged by an array of solar cc.°lls fib through a charging circuit b4), and s various system and vehicle sensors EiBA-68D,. as well as a low power local transceiver 70 and a microprocessor 72. l~'lic~°op~~oc;essor 72 is interfaced to all of the other elements of the tracking unit and has control over them.
Transceiver 70 may be a commercially available spread spectrum transceiver such as those currently utilized in wireless local area networks. Spread uo spectnrm transceiver 70 is equipped with its c~wn low profile antenna 7~t.
Utilizing local transceiver 7t), microprocessor 72 communicates with all other tracking units within communications ranl.;e. When a train has multiple freight cars 82,, 82z, . . . ., 82r, equipped with these tracking units, as shown in Figure 3, all of these units exchange information. E~ecause the microprocessors u5 are interfaced to their own pcawer sources, the status of available power for each tracking unit can also be exchanged. In accordance with the inventions disclosed in the aforementioned Canadian application Serial No. 2,176,869 entitled "Local Communication Network for Power Reduction and Enhanced Reliability in a Multiple Node Tracking System" by Welles et al. and Canadian application r o Serial. No. 2,176,882 entitled "Protocol and Mechanism for Primary and Mutter Mode Communication for Asset 'lyracking" by Ali et al., the tracking unit with the most available power (i.e., most fully charged batteries) will become the designated master unit, the other units being slave units. The master unit performs the GPS position and velocity data reci;pcion function, assembles these >5 data along with the IDs of all othier tracking units oro the train, and transmits this information periodically in a single packet to a central station 8~ via communication satellite 86.
In accordance with the present invention, the master tracking unit does not perform the GI'S location and velocity reception function; rather, ao this function is performed by tile GPS system on board the locomotive, thereby saving considerable powor- irr tI~rET operatic:m of the master tracking unit. The master tracking unit performs all tl~e othc;r functions .as described above, including maintaining a list of IDs oi~the, members ofthe mutter group. The master tracking ~~nii pei°iodically transrnts this information to the ~~~~883 -23,532 -g_ locomotive. The locomotive, in turn, locates itself using the GPS system and transmits its location and the data collected by the master tracking unit of the mutter network to the central station. The master tracking unit thus performs the function of a network administrator, leaving the power demanding functions to the locomotive.
To implement the protocol according to the invention, a two-way communication link between the locomotive transceiver and each of the asset tracking units is first established. This protocol is preferably a Tirne Division Multiple Access (TDMA) protocol The TDMA protocol requires l0 each tracking unit to ttartsmit in an assigned time slot during which no other unit transmits. A TDMA system requires sacking units to be time synchronized to prevent message "collisions" (i.e., interference between simultaneously transmitted signals). This can be accomplished using GPS
absolute time as a reference transmitted by the locomotive transceiver, for example. The various tracking units are also assigned transmission frequencies and time slots by the central station.
The tracking units, using the TDMA system, transmit on the assigned frequency and time slot. The locomotive transceiver receives data from the different tracking uniu, and an on-board computer decodes the information and stores the information in a table. Each row of the table has at least three entries; namely, unit ID, battery strength and signal quality.
Signal quality can be selected to be received signal strength, bit error rate measured over a known sync word or carrier-to-interference ratio. The tracking units are formed into a LAN rcfeacd to as a "muttei' group. The master tracking unit periodically polls the tracking units in its mutter group, and the collected data are then transmitted by the master unit to the locomotive transceiver and thence via satellite Link to the central station.
This conserves battery power as other tracking units in the mutter group, especially those with low battery power, do not have to transmit except at infrequentintervals.
The master tracking unit is selected as follows. From each of the groups in the table generated by the computer on board the locomotive, the tracking units are sorted by battery strength and signal quality to determine the unit with not only the best battery strength but also the one with the best propagation path to the satellite. If no single tracking unit is best in both -23,532 2 ~ '~ 6 8 8 3 categories, a compromise, or trade-off is made. Use of the signal quality measure in selecting the best tracking unit helps overcome effects such as shadowing, and provides inherent diversity. That, is, if the tracking unit with the highest battery strength is under a canopy (e.g., tunnel, foliage, ice or awning), then there is no point in choosing that unit to forward the group's data to the locomotive tracking unit as considerabie power must be expended to overcome the attenuation of the canopy.
Alternatively, the locomotive computer and transceiver can act as the master unit and all the a~acking units attached to railcars in the consist serve l0 as slave units to the locomotive unit. This has the advantage of providing the master unit with access to the unlimited power available to the locomotive. A primary disadvantage of this arrangement is that a train can be quite long, requiring much battery power and signal strength to transmit a good quality signal from a remote end of the train to the locomotive. This 15 can result in loss of reliability of the diversity of the mutter network.
If the master tracking unit can be selected to be at a location near the middle of the train, the average distance of transmission from a slave unit to the selected master unit is reduced, thereby improving reliability of the signal.
Figure 4, illustrates the process implemented by the tracking unit 20 selected to be the master unit in the mutter group forming the LAN. On a periodic basis, the master tracking unit, acting as the network administrator of the mutter group, polls the tracking units in its list and waits for a response. For each slave unit, the master unit goes through a similar logic.
The tracking unit mode is set to master at step 401. The master unit is in a 25 standby or "sleep" mode until the slave unit polling time at step 402. At that time, the master unit is activated, or "wakes up", and transmits a poll to the slave unit at step 403. A test is then made at decision step 404 to determine whether a reply was received from the slave unit. If so, the information received from the slave unit is stored at step 405, and the failure count for 30 that slave unit is set to zero at step 406. The process then loops back to function block 402. If, however, a reply is not received from the slave unit, the failure count for that unit is incremented at step 407. A test is made at decision step 408 to determine if the failure count for that slave unit is equal to six. If not, the process loops back to step 402; otherwise, the slave unit is 35 removed from the masters slave list at step 409. Next, a test is made at -23,532 decision step 410 to detemvne if all the slaves on the mastei s slave list have been polled. If not, the process loops back to step 402. When all the slave tracking units have been polled and at a predetermined time, the master tracking unit transmits the collected data to the locomotive at step 411, and the process exits.
Figure 5 illustrates by way of a flow diagram the process implemented by the computer on board the locomotive. The locomotive, using its GPS receiver (i.e., navigation set) periodically detemtines its current location and velocity, as indicated at step 501. These data are 1o temporarily stored in a frame buffer at step 502. The locomotive transceiver awaits the transmission from the master tracking unit during a time window centered on the predetermined time of transmission by the master tracking unit at step 503. The data received from the master tracking unit acting as the administrator unit of the muaer group is also temporarily stored in the frame buffer at step 504. Finally, during its assigned tune slot, the locomotive aanscciver transmits the data accumulated in the frame buffer to the central station at step SOS.
While only certain preferred features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover ail such modifications and changes as fall within the true spirit of the invention.
NETWORKS
AND LOCOMOTIVE TRANSMITTER
DURING TRANSIT
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to asset sacking and, more particularly, to tracking of assets, such as railcars, during transit, using the Global Positioning System (GPS).
Bockgroiutd Description Goods shipped from a manufacturing plant, warehouse or port of entry to a destination are nom~ally tracked to assure their timely and safe delivery. Tracking has heretofore been accomplished in part by use of shipping documents and negotiable instruments, some of which travel with the goods and others of which are transmitted by post or courier to a receiving destination. This paper sacking provides a record which is completed only on the safe delivery and acceptance of the goods. However, there sometimes is a need to know the location of the goods while in transit.
Knowledge of the location of the goods can be used for inventory control, scheduling and monitoring.
Shippers have provided information on the location of goods by tracking their vehicles, knowing what goods are loaded on those vehicles.
Goods are often loaded aboani shipping containers or container trucks, for example, which are in turn loaded aboard railcars. Various devices have been used to track such vehicles. In the case of railcars, passive radio frequency (RF) transponders mounted on the cars have been used to facilitate interrogation of each car as it passes a way station and supply the car's identification (ID). This information is tlxn transmitted by a rndiated -23.532 signal or land line to a central station which tracks the locations of cars.
This technique, however, is deficient in that any traits on a siding cannot pass a way station until it has left the siding, which could involve a considerable delay. Moreover, way station installations are expensive, requiring a compromise that results in way stations being installed at varying distances, depending on the track layout Thus, the precision of location information varies from place to place on the railroad.
Recently, mobile tracking units have been used for tracking various types of vehicles, such as trains. Communication has been provided by means of cellular mobile telephone or RF radio link. Such mobile tracking units are generally installed aboard the locomotive which provides a ready source of power. However, in the case of shipping containers, container truck trailers and railcars, a similar source of power is not readily available.
Mobile tracking units which might be attached to containers and vehicles 13 must be power efficient in order to provide reliable and economical operation.
Most current asset tracking systems are land-based systems wherein a radio unit on the asset transmits information to wayside stations of a fixed network, such as the public land mobile radio network or a cellular network. These networks do not have ubiquitous coverage, and the asset tracking units are expensive. A satellite-based truck sacking system developed by Qualcomm Inc., known as OMNTfRACS, is in operation in the United States and Canada. This system requires a specialized directional antenna and considerable power for operation, while vehicle location, 23 derived from two satellites, is obtained to an accuracy of about one-fourth kilometer. A rail vehicle positioning system described in U.S. Patent No.
5,129,605 to Bums et al. is installed on the locomotive of a train and uses, as inputs to generate a location report, a GPS receiver, a wheel tachometer, transponders, and manual inputs from the locomotive engineer. While the Bums et al. system is accurate for locating a locomotive, it is not adaptable for locating individual railcars in a train. The problem of locating railcars is exacerbated by the fact that railcars in a consist may be removed or added during a particular locomotive's aansit ftrom a starting point to an ultimate destination. Therefore, knowledge of a locomotive's location is not a 33 roliable indication of the location of railcars.
RD-23,532 _3..
In an asset tracking system disclosed in Canadian application Serial No.
2,176,869 filed May 17, 1906 entitled "Local C:'ommunication Network for Power Reduction and Enhanced Reliability in a Multilale Node Tracking System"
by Welles et al. and in C~madian application Set°ial No. 2,176,882 bled May 17, s 1996, entitled "Protocol and Mechanism for Primary and Mutter Mode Communication for Asset Tracking" by Ali et al., assigned to the instant assignee, a tracking system based on a "trzutter" mode local area network is used to generate data which are transmitted to a central station. In this asset tracking system, there are two modes of eomrnunic.ation. Clne mode is to communication between the central station and the tracking units, which is usually via satellite. The second mode is a local area network, referred to as the "mutter" mode, between tracl~ing units. C>ne of the mobile units, denoted the master unit, communicates with the central station. While this asset tracking system is a reliable ar7d accurate system for tracking a ssets during i5 transit, it would be desirable to provide a GP~i receiver and satellite for use of a locomotive in conjunction mobile tracking units on board the railcars and joined in a local area network (LAN).
SUMMARY' OFTHF INVFN'TION
It is therefore an object of the invention to provide a system for ~o global localization of railcars in transit.
Another object of the invention is to provide a method for tracking railcars in transit that does not re,~uire an unlimited power source.
According to the; invention, locatiat~ <nf a railcar is determined using a CJPS receiver and a satellite iransc;eiver on hoard the locomotive and a ?s LAN of railcar tracking units. Instead of conxputing the GPS solution independently and transmitting it to a central station, the railcar tracking units transmit their unique 1Ds to one of the tracking units in the LAN which acts as an administrator unit. 'f he administrator unit, in turn, maintains a list of IDs and periodically transmits the list of LI~s to the locomotive. The 30 locomotive locates itself using the GPS system and periodically transmits its position and velocity to the central station.
More particularly, the I.AN formed by the tracking units on board -23,532 the railcars in a train is leaned a "mutter" network, and selects a master tracking unit which serves as an administrator unit The other tracking units in the network operates as slaves to the selected master unit. The administrator unit of the network communicates with the transceiver of the locomotive. The locomotive contains a GPS location device in conjunction with an on-board transceiver used to communicate with the central station.
The administrator unit transmits to the locomotive transceiver a list of railcar IDs in the LAN. The locomotive transceiver then transmits to the central station, via appropriate medium, the list of railcars along with the location and velocity of the locomotive. On reaching the destination, just before taming itself off, the locomotive transceiver sends to the central station the list of railcar IDs and their current location as calculated by the locomotive GPS receiver.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention believed to be novel are set forth in the appended claims. The invention, however, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings) in which:
Figtue 1 is a block diagram of an exemplary asset tracking system which employs mobile tracking units and operates in accordance with the method of the present invention;
Figure 2 is a block diagram showing in furtiter detail a mobile tracking unit as used in the asset tracking system shown in Figure I;
Figure 3 is a block diagram illusaating organization of the mobile local area network implemented by the present invention;
Figure 4 is a flow diagram showing the steps in operation of the selocted master tracking unit; and Figure 5 is a flow diagram showing the steps in operation of the computer on board the locomotive.
DETAILED DESCRIPTION OF A PREFERRED
EMBODIMENT OF THE INVENTION
~7-23,532 Figure 1, illustrates mobile tracking units which employ navigation signals from a GPS satellite constellation, although, as suggested above, other navigation systems can be used in lieu of GPS. A set of mobile tracking units l0A-lOD are installed in respective railcars 12A-12D, which are to be tracked or monitored. A communication link 14, such as a satellite communication link through a communication satellite 16, is provided between the locomotive and a remote central station 18 manned by one or more operators and having suitable display devices and the like for displaying location and status information for each railcar equipped with a respective mobile tracking unit. Communication link 14 can be conveniently used for transmitting vehicle conditions or events measured with suitable sensing elements. Communication link 14 may be one-way (from the locomotive to the centtal station) or two-way. In a two-way communication link, messages and commands can be sent to the locomotive transceiver, thereby further enhancing reliability of the communication. A constellation of GPS satellites, such as GPS satellites 20A and 20B, provides highly accurate navigation signals which can be used to deterntine vehicle location and velocity when the signals are acquired by a suitable GPS receiver.
Briefly, the GPS was developed by the U.S. Department of Defense and gradually placed into service throughout the 1980s. The GPS satellites constantly transmit radio signals in L-Band frequency using spread spectrum techniques. The transmitted radio signals carry pseudotandom sequences which allow users to determine location on the surface of the earth (within approximately 100 feet), velocity (within about 0.1 MPH), ~d P~~ tire information. GPS is a particularly attractive navigation system to employ, being that the respective orbits of the GPS satellites are chosen so as to provide world-wide coverage and being that such highly-accurate radio signals are provided fret of charge to users by the U.S. federal government.
A locomotive mobile tracking unit, such as shown in Figure 2, includes an on boani navigation set SO capable of generating data substantially corresponding to the locomotive location. Choice of navigation set depends on the particular navigation system used for supplying 3s navigation signals to the mobile tracking unit. Preferably, the navigation set ~D-23,532 2 ~ ~ ~ g g 3 is a GPS receiver such as a multichannel receiver, however, other receivers designed for acquiring signals from a corresponding navigation system may alternatively be employed. For example, depending on the locomotive location accuracy requirements, the navigation set may comprise a Loran-C
receiver or other such less highly-accurate navigation receiver than a GPS
receiver. Further, the navigation set may conveniently comprise a transceiver that inherently provides two-way communication with the central station and avoids the need for separately operating an additional component to implement such two-way communication. Briefly, such transceiver t0 would allow for implementation of satellite range measurement techniques being that the position of the locomotive is simply detemtined at the central station by range measurements to the locomotive and the central station from two satellites whose position in space is known. A key advantage of the present invention is the ability to substantially reduce the total energy required by the mobile tracking units on board a train propelled by the locomotive by utilizing the effectively unlimited power of the locomotive for the GPS navigation set and the transceiver for communicating with the central station.
Mobile tracking unit 10, as shown in Figure Z, includes a suitable electromagnetic transceiver 52, which may comprise a commercially available spread specavm transceiver such as those currently being utilized in wireless LANs. A low profile antenna 54 is coupled to transceiver 52 and navigation sec 50, to serve both. Both transceiver 52 and navigation set 50 are activated by a controller 58 which, in turn, is responsive to signals from a clock module 60. Transceiver 52 is capable of transmitting the vehicle location data by way of communication link 14 (Figure 1) to the central station and receiving commands from the central station by way of the same link. If a GPS receiver is used, the GPS receiver and the transceiver can be conveniently integrated as a single unit for maximizing efficiency of installation and operation. An example of one such integrated unit is the Galaxy lnmarsatGGPS integrated unit, which is available from Trimble Navigation, Sunnyvale, California, and is conveniently designed for data communication and position reporting between the central station and the mobile tracking unit.
A low power, short distance radio link permits joining the nearby RI7-23,532 _7..
mobile tracking units in a network to conserve pc:awer and maintain high reliability and functionality of such network. l:;ach tracking unfit also includes a power source (which comprises a battery pack that can be charged by an array of solar cc.°lls fib through a charging circuit b4), and s various system and vehicle sensors EiBA-68D,. as well as a low power local transceiver 70 and a microprocessor 72. l~'lic~°op~~oc;essor 72 is interfaced to all of the other elements of the tracking unit and has control over them.
Transceiver 70 may be a commercially available spread spectrum transceiver such as those currently utilized in wireless local area networks. Spread uo spectnrm transceiver 70 is equipped with its c~wn low profile antenna 7~t.
Utilizing local transceiver 7t), microprocessor 72 communicates with all other tracking units within communications ranl.;e. When a train has multiple freight cars 82,, 82z, . . . ., 82r, equipped with these tracking units, as shown in Figure 3, all of these units exchange information. E~ecause the microprocessors u5 are interfaced to their own pcawer sources, the status of available power for each tracking unit can also be exchanged. In accordance with the inventions disclosed in the aforementioned Canadian application Serial No. 2,176,869 entitled "Local Communication Network for Power Reduction and Enhanced Reliability in a Multiple Node Tracking System" by Welles et al. and Canadian application r o Serial. No. 2,176,882 entitled "Protocol and Mechanism for Primary and Mutter Mode Communication for Asset 'lyracking" by Ali et al., the tracking unit with the most available power (i.e., most fully charged batteries) will become the designated master unit, the other units being slave units. The master unit performs the GPS position and velocity data reci;pcion function, assembles these >5 data along with the IDs of all othier tracking units oro the train, and transmits this information periodically in a single packet to a central station 8~ via communication satellite 86.
In accordance with the present invention, the master tracking unit does not perform the GI'S location and velocity reception function; rather, ao this function is performed by tile GPS system on board the locomotive, thereby saving considerable powor- irr tI~rET operatic:m of the master tracking unit. The master tracking unit performs all tl~e othc;r functions .as described above, including maintaining a list of IDs oi~the, members ofthe mutter group. The master tracking ~~nii pei°iodically transrnts this information to the ~~~~883 -23,532 -g_ locomotive. The locomotive, in turn, locates itself using the GPS system and transmits its location and the data collected by the master tracking unit of the mutter network to the central station. The master tracking unit thus performs the function of a network administrator, leaving the power demanding functions to the locomotive.
To implement the protocol according to the invention, a two-way communication link between the locomotive transceiver and each of the asset tracking units is first established. This protocol is preferably a Tirne Division Multiple Access (TDMA) protocol The TDMA protocol requires l0 each tracking unit to ttartsmit in an assigned time slot during which no other unit transmits. A TDMA system requires sacking units to be time synchronized to prevent message "collisions" (i.e., interference between simultaneously transmitted signals). This can be accomplished using GPS
absolute time as a reference transmitted by the locomotive transceiver, for example. The various tracking units are also assigned transmission frequencies and time slots by the central station.
The tracking units, using the TDMA system, transmit on the assigned frequency and time slot. The locomotive transceiver receives data from the different tracking uniu, and an on-board computer decodes the information and stores the information in a table. Each row of the table has at least three entries; namely, unit ID, battery strength and signal quality.
Signal quality can be selected to be received signal strength, bit error rate measured over a known sync word or carrier-to-interference ratio. The tracking units are formed into a LAN rcfeacd to as a "muttei' group. The master tracking unit periodically polls the tracking units in its mutter group, and the collected data are then transmitted by the master unit to the locomotive transceiver and thence via satellite Link to the central station.
This conserves battery power as other tracking units in the mutter group, especially those with low battery power, do not have to transmit except at infrequentintervals.
The master tracking unit is selected as follows. From each of the groups in the table generated by the computer on board the locomotive, the tracking units are sorted by battery strength and signal quality to determine the unit with not only the best battery strength but also the one with the best propagation path to the satellite. If no single tracking unit is best in both -23,532 2 ~ '~ 6 8 8 3 categories, a compromise, or trade-off is made. Use of the signal quality measure in selecting the best tracking unit helps overcome effects such as shadowing, and provides inherent diversity. That, is, if the tracking unit with the highest battery strength is under a canopy (e.g., tunnel, foliage, ice or awning), then there is no point in choosing that unit to forward the group's data to the locomotive tracking unit as considerabie power must be expended to overcome the attenuation of the canopy.
Alternatively, the locomotive computer and transceiver can act as the master unit and all the a~acking units attached to railcars in the consist serve l0 as slave units to the locomotive unit. This has the advantage of providing the master unit with access to the unlimited power available to the locomotive. A primary disadvantage of this arrangement is that a train can be quite long, requiring much battery power and signal strength to transmit a good quality signal from a remote end of the train to the locomotive. This 15 can result in loss of reliability of the diversity of the mutter network.
If the master tracking unit can be selected to be at a location near the middle of the train, the average distance of transmission from a slave unit to the selected master unit is reduced, thereby improving reliability of the signal.
Figure 4, illustrates the process implemented by the tracking unit 20 selected to be the master unit in the mutter group forming the LAN. On a periodic basis, the master tracking unit, acting as the network administrator of the mutter group, polls the tracking units in its list and waits for a response. For each slave unit, the master unit goes through a similar logic.
The tracking unit mode is set to master at step 401. The master unit is in a 25 standby or "sleep" mode until the slave unit polling time at step 402. At that time, the master unit is activated, or "wakes up", and transmits a poll to the slave unit at step 403. A test is then made at decision step 404 to determine whether a reply was received from the slave unit. If so, the information received from the slave unit is stored at step 405, and the failure count for 30 that slave unit is set to zero at step 406. The process then loops back to function block 402. If, however, a reply is not received from the slave unit, the failure count for that unit is incremented at step 407. A test is made at decision step 408 to determine if the failure count for that slave unit is equal to six. If not, the process loops back to step 402; otherwise, the slave unit is 35 removed from the masters slave list at step 409. Next, a test is made at -23,532 decision step 410 to detemvne if all the slaves on the mastei s slave list have been polled. If not, the process loops back to step 402. When all the slave tracking units have been polled and at a predetermined time, the master tracking unit transmits the collected data to the locomotive at step 411, and the process exits.
Figure 5 illustrates by way of a flow diagram the process implemented by the computer on board the locomotive. The locomotive, using its GPS receiver (i.e., navigation set) periodically detemtines its current location and velocity, as indicated at step 501. These data are 1o temporarily stored in a frame buffer at step 502. The locomotive transceiver awaits the transmission from the master tracking unit during a time window centered on the predetermined time of transmission by the master tracking unit at step 503. The data received from the master tracking unit acting as the administrator unit of the muaer group is also temporarily stored in the frame buffer at step 504. Finally, during its assigned tune slot, the locomotive aanscciver transmits the data accumulated in the frame buffer to the central station at step SOS.
While only certain preferred features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover ail such modifications and changes as fall within the true spirit of the invention.
Claims (4)
1. A method of tracking railcar's in a train including a locomotive, said locomotive including a global positioning satellite (GPS) receiver and a transceiver for communicating with a central station, said method comprising the steps of:
affixing a battery powered tracking unit to each one of a plurality of railcars in the train;
forming a local area network of tracking units in the train, said local area network including a single administrator tracking unit selected among the tracking units;
periodically reporting a unique identification (ID) from each respective one of said tracking units in the network to the administrator tracking unit;
maintaining by the administrator tracking unit a list of tracking units by ID;
periodically reporting from the administrator tracking unit to the transceiver the list of tracking units; and periodically reporting from the transceiver to a central station a GPS
position and the list of tracking units.
affixing a battery powered tracking unit to each one of a plurality of railcars in the train;
forming a local area network of tracking units in the train, said local area network including a single administrator tracking unit selected among the tracking units;
periodically reporting a unique identification (ID) from each respective one of said tracking units in the network to the administrator tracking unit;
maintaining by the administrator tracking unit a list of tracking units by ID;
periodically reporting from the administrator tracking unit to the transceiver the list of tracking units; and periodically reporting from the transceiver to a central station a GPS
position and the list of tracking units.
2. The method of tracking railcars in a train as recited in claim 1 and further comprising the step of updating the list of tracking units by the administrator tracking unit when railcars are removed or added to the train.
3. The method of tracking railcars in a train as recited in claim 2 and further comprising the steps of:
periodically transmitting polls at specified times from the administrator tracking unit to tracking units on the list of tracking units;
determining whether a response has been received from each tracking unit polled by the administrator tracking unit;
counting by the administrator tracking unit, for each tracking unit on the list a number of consecutive failures to receive a response from polls; and removing from the list of tracking units any tracking unit for which the number of consecutive failures exceeds a predetermined value.
periodically transmitting polls at specified times from the administrator tracking unit to tracking units on the list of tracking units;
determining whether a response has been received from each tracking unit polled by the administrator tracking unit;
counting by the administrator tracking unit, for each tracking unit on the list a number of consecutive failures to receive a response from polls; and removing from the list of tracking units any tracking unit for which the number of consecutive failures exceeds a predetermined value.
4. The method of tracking railcars in a train as recited in claim 3 and further comprising the step of notifying the central station from the transceiver that a tracking unit has been removed from the list of tracking units for the train.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/484,752 US5682139A (en) | 1995-06-07 | 1995-06-07 | Railcar location using mutter networks and locomotive transmitter during transit |
| US08/484,752 | 1995-06-07 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2176883A1 CA2176883A1 (en) | 1996-12-08 |
| CA2176883C true CA2176883C (en) | 2005-12-06 |
Family
ID=23925461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002176883A Expired - Fee Related CA2176883C (en) | 1995-06-07 | 1996-05-17 | Railcar location using mutter networks and locomotive transmitter during transit |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5682139A (en) |
| EP (1) | EP0748081A1 (en) |
| JP (1) | JP3824280B2 (en) |
| CA (1) | CA2176883C (en) |
| IL (1) | IL118421A (en) |
Families Citing this family (130)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6897780B2 (en) * | 1993-07-12 | 2005-05-24 | Hill-Rom Services, Inc. | Bed status information system for hospital beds |
| US5715174A (en) * | 1994-11-15 | 1998-02-03 | Absolute Software Corporation | Security apparatus and method |
| US6226622B1 (en) * | 1995-11-27 | 2001-05-01 | Alan James Dabbiere | Methods and devices utilizing a GPS tracking system |
| JP2920879B2 (en) * | 1996-10-09 | 1999-07-19 | 川崎重工業株式会社 | Logistics / transportation system |
| US6218961B1 (en) | 1996-10-23 | 2001-04-17 | G.E. Harris Railway Electronics, L.L.C. | Method and system for proximity detection and location determination |
| US5902341A (en) * | 1996-10-30 | 1999-05-11 | Scientific-Atlanta, Inc. | Method and apparatus to automatically generate a train manifest |
| US8982856B2 (en) | 1996-12-06 | 2015-03-17 | Ipco, Llc | Systems and methods for facilitating wireless network communication, satellite-based wireless network systems, and aircraft-based wireless network systems, and related methods |
| US7054271B2 (en) | 1996-12-06 | 2006-05-30 | Ipco, Llc | Wireless network system and method for providing same |
| US8466795B2 (en) | 1997-01-21 | 2013-06-18 | Pragmatus Mobile LLC | Personal security and tracking system |
| US5986547A (en) | 1997-03-03 | 1999-11-16 | Korver; Kelvin | Apparatus and method for improving the safety of railroad systems |
| FR2762168B1 (en) * | 1997-04-10 | 1999-05-07 | Alsthom Cge Alcatel | MOBILE STATION INTEGRATING RADIOCOMMUNICATION AND LOCATION FUNCTIONS, AND CORRESPONDING METHOD FOR RECEIVING LOCATION SIGNALS BY A MOBILE STATION |
| JP3374042B2 (en) * | 1997-05-16 | 2003-02-04 | 本田技研工業株式会社 | Inter-vehicle communication method |
| US6057779A (en) * | 1997-08-14 | 2000-05-02 | Micron Technology, Inc. | Method of controlling access to a movable container and to a compartment of a vehicle, and a secure cargo transportation system |
| CA2305142A1 (en) | 1997-11-07 | 1999-05-20 | Hill-Rom, Inc. | Mobile surgical support apparatus |
| US5969643A (en) * | 1998-02-23 | 1999-10-19 | Westinghouse Air Brake Company | Method and apparatus for determining relative locomotive position in a train consist |
| US5977909A (en) * | 1998-03-13 | 1999-11-02 | General Electric Company | Method and apparatus for locating an object using reduced number of GPS satellite signals or with improved accuracy |
| US6104978A (en) * | 1998-04-06 | 2000-08-15 | General Electric Company | GPS-based centralized tracking system with reduced energy consumption |
| DE19816435C1 (en) * | 1998-04-15 | 1999-06-17 | Deutsche Bahn Ag | Satellite locating apparatus |
| US6437692B1 (en) | 1998-06-22 | 2002-08-20 | Statsignal Systems, Inc. | System and method for monitoring and controlling remote devices |
| US6914893B2 (en) | 1998-06-22 | 2005-07-05 | Statsignal Ipc, Llc | System and method for monitoring and controlling remote devices |
| US6028522A (en) * | 1998-10-14 | 2000-02-22 | Statsignal Systems, Inc. | System for monitoring the light level around an ATM |
| US8410931B2 (en) | 1998-06-22 | 2013-04-02 | Sipco, Llc | Mobile inventory unit monitoring systems and methods |
| US6218953B1 (en) | 1998-10-14 | 2001-04-17 | Statsignal Systems, Inc. | System and method for monitoring the light level around an ATM |
| US6891838B1 (en) | 1998-06-22 | 2005-05-10 | Statsignal Ipc, Llc | System and method for monitoring and controlling residential devices |
| US20020013679A1 (en) * | 1998-10-14 | 2002-01-31 | Petite Thomas D. | System and method for monitoring the light level in a lighted area |
| US6463272B1 (en) | 1998-12-21 | 2002-10-08 | Intel Corporation | Location reporting pager |
| US7034690B2 (en) * | 1999-02-09 | 2006-04-25 | Hill-Rom Services, Inc. | Infant monitoring system and method |
| US10973397B2 (en) | 1999-03-01 | 2021-04-13 | West View Research, Llc | Computerized information collection and processing apparatus |
| US8636648B2 (en) | 1999-03-01 | 2014-01-28 | West View Research, Llc | Endoscopic smart probe |
| US7650425B2 (en) * | 1999-03-18 | 2010-01-19 | Sipco, Llc | System and method for controlling communication between a host computer and communication devices associated with remote devices in an automated monitoring system |
| US6985750B1 (en) | 1999-04-27 | 2006-01-10 | Bj Services Company | Wireless network system |
| US6422628B1 (en) | 1999-05-10 | 2002-07-23 | Veridian Erim International, Inc. | Transportable satellite communication station including double-expandable trailer |
| GB9911170D0 (en) * | 1999-05-14 | 1999-07-14 | Aea Technology Plc | Track monitoring equipment |
| US7027773B1 (en) | 1999-05-28 | 2006-04-11 | Afx Technology Group International, Inc. | On/off keying node-to-node messaging transceiver network with dynamic routing and configuring |
| AU5158800A (en) * | 1999-05-28 | 2000-12-18 | Basic Resources, Inc. | Wireless transceiver network employing node-to-node data messaging |
| US8065155B1 (en) | 1999-06-10 | 2011-11-22 | Gazdzinski Robert F | Adaptive advertising apparatus and methods |
| US7710273B2 (en) * | 1999-09-02 | 2010-05-04 | Round Rock Research, Llc | Remote communication devices, radio frequency identification devices, wireless communication systems, wireless communication methods, radio frequency identification device communication methods, and methods of forming a remote communication device |
| US6539393B1 (en) * | 1999-09-30 | 2003-03-25 | Hill-Rom Services, Inc. | Portable locator system |
| US6487393B1 (en) | 1999-10-04 | 2002-11-26 | General Electric Company | Method for data exchange with a mobile asset considering communication link quality |
| US7236462B2 (en) | 1999-10-04 | 2007-06-26 | General Electric Company | Method for data exchange with a mobile asset considering communication link quality |
| AU2298801A (en) * | 1999-10-21 | 2001-04-30 | Pinpoint Corporation | Method and apparatus for low cost asset location |
| MXPA02006553A (en) * | 1999-12-30 | 2003-04-10 | Ge Transp Systems Global Signa | Methods and apparatus for locomotive position determination. |
| US6697752B1 (en) | 2000-05-19 | 2004-02-24 | K&L Technologies, Inc. | System, apparatus and method for testing navigation or guidance equipment |
| FR2818058B1 (en) * | 2000-12-13 | 2008-10-24 | Thomson Csf | METHOD AND SYSTEM FOR EXCHANGING INFORMATION BETWEEN A MAIN STATION AND A CLUSTER OF MOBILE STATIONS |
| US8458754B2 (en) * | 2001-01-22 | 2013-06-04 | Sony Computer Entertainment Inc. | Method and system for providing instant start multimedia content |
| US7242306B2 (en) | 2001-05-08 | 2007-07-10 | Hill-Rom Services, Inc. | Article locating and tracking apparatus and method |
| CA2445161A1 (en) | 2001-05-08 | 2002-11-14 | Hill-Rom Services, Inc. | Article locating and tracking system |
| US8489063B2 (en) | 2001-10-24 | 2013-07-16 | Sipco, Llc | Systems and methods for providing emergency messages to a mobile device |
| US7480501B2 (en) | 2001-10-24 | 2009-01-20 | Statsignal Ipc, Llc | System and method for transmitting an emergency message over an integrated wireless network |
| US7424527B2 (en) | 2001-10-30 | 2008-09-09 | Sipco, Llc | System and method for transmitting pollution information over an integrated wireless network |
| AUPR910301A0 (en) * | 2001-11-26 | 2001-12-20 | Marine-Watch Limited | Satellite system for vessel identification |
| US7711847B2 (en) | 2002-04-26 | 2010-05-04 | Sony Computer Entertainment America Inc. | Managing users in a multi-user network game environment |
| RU2308045C2 (en) | 2002-05-07 | 2007-10-10 | Агротек Корпорейшн | Method and system for tracking |
| US6862502B2 (en) | 2002-05-15 | 2005-03-01 | General Electric Company | Intelligent communications, command, and control system for a land-based vehicle |
| US7421471B2 (en) * | 2002-05-17 | 2008-09-02 | Sony Computer Entertainment America Inc. | Configuration switching: dynamically changing between network communication architectures |
| US20030217135A1 (en) | 2002-05-17 | 2003-11-20 | Masayuki Chatani | Dynamic player management |
| US7606920B2 (en) * | 2002-05-17 | 2009-10-20 | Sony Computer Entertainment America Inc. | Method and apparatus for controlling communication ports for an online session of a multi-user application by associating each of the ports with a protocol and designating an active port |
| AU2003245650A1 (en) * | 2002-06-24 | 2004-01-06 | Manickam A. Gounder | Cargo container locking system and method |
| US8560707B2 (en) * | 2007-10-05 | 2013-10-15 | Sony Computer Entertainment America Llc | Seamless host migration based on NAT type |
| US8131802B2 (en) | 2007-10-05 | 2012-03-06 | Sony Computer Entertainment America Llc | Systems and methods for seamless host migration |
| US7792089B2 (en) * | 2002-07-31 | 2010-09-07 | Cattron-Theimeg, Inc. | System and method for wireless remote control of locomotives |
| US7734476B2 (en) | 2002-09-27 | 2010-06-08 | Hill-Rom Services, Inc. | Universal communications, monitoring, tracking, and control system for a healthcare facility |
| US8601606B2 (en) | 2002-11-25 | 2013-12-03 | Carolyn W. Hafeman | Computer recovery or return |
| MXPA05008287A (en) | 2003-02-10 | 2005-09-20 | Nielsen Media Res Inc | Methods and apparatus to adaptively gather audience information data. |
| US7323981B2 (en) * | 2003-02-20 | 2008-01-29 | Global Statistics, Inc. | Container tracking system |
| US6870476B2 (en) * | 2003-04-07 | 2005-03-22 | Bulldog Technologies Inc. | Continuous feedback container security system |
| US7399205B2 (en) | 2003-08-21 | 2008-07-15 | Hill-Rom Services, Inc. | Plug and receptacle having wired and wireless coupling |
| US20050055432A1 (en) * | 2003-09-08 | 2005-03-10 | Smart Synch, Inc. | Systems and methods for remote power management using 802.11 wireless protocols |
| US7289887B2 (en) * | 2003-09-08 | 2007-10-30 | Smartsynch, Inc. | Systems and methods for remote power management using IEEE 802 based wireless communication links |
| US7427024B1 (en) | 2003-12-17 | 2008-09-23 | Gazdzinski Mark J | Chattel management apparatus and methods |
| KR100741152B1 (en) * | 2004-01-07 | 2007-07-20 | 후아웨이 테크놀러지 컴퍼니 리미티드 | A method for reducing interface load of home subscriber server |
| JP4466269B2 (en) * | 2004-08-06 | 2010-05-26 | セイコーエプソン株式会社 | Electronic device and portable electronic device |
| EP1713183A1 (en) * | 2004-01-19 | 2006-10-18 | Seiko Epson Corporation | Electronic device and radio communication terminal |
| WO2005082696A1 (en) * | 2004-02-24 | 2005-09-09 | General Electric Company | Rail car tracking system |
| US7756086B2 (en) | 2004-03-03 | 2010-07-13 | Sipco, Llc | Method for communicating in dual-modes |
| US8031650B2 (en) | 2004-03-03 | 2011-10-04 | Sipco, Llc | System and method for monitoring remote devices with a dual-mode wireless communication protocol |
| US7319386B2 (en) | 2004-08-02 | 2008-01-15 | Hill-Rom Services, Inc. | Configurable system for alerting caregivers |
| US7852208B2 (en) | 2004-08-02 | 2010-12-14 | Hill-Rom Services, Inc. | Wireless bed connectivity |
| US9439126B2 (en) | 2005-01-25 | 2016-09-06 | Sipco, Llc | Wireless network protocol system and methods |
| US7487614B1 (en) * | 2005-01-27 | 2009-02-10 | Seth Walker | Radio controlled gill net recovery transmitters |
| US9547780B2 (en) * | 2005-03-28 | 2017-01-17 | Absolute Software Corporation | Method for determining identification of an electronic device |
| US7492810B2 (en) | 2005-04-04 | 2009-02-17 | General Electric Company | Method and apparatus for segmented code correlation |
| CN101346268B (en) * | 2005-12-23 | 2012-04-25 | Asf-基斯通公司 | Railroad train monitoring system |
| US20070170314A1 (en) * | 2006-01-26 | 2007-07-26 | Kane Mark E | Method and system for locating end of train units |
| MX2007015979A (en) * | 2006-03-31 | 2009-04-07 | Nielsen Media Res Inc | Methods, systems, and apparatus for multi-purpose metering. |
| US7698962B2 (en) * | 2006-04-28 | 2010-04-20 | Amsted Rail Company, Inc. | Flexible sensor interface for a railcar truck |
| US20080143593A1 (en) * | 2006-12-14 | 2008-06-19 | General Electric | System and method for providing asset management and tracking capabilities |
| US8171858B2 (en) * | 2006-12-20 | 2012-05-08 | Advanced Maglev Systems, Llc | Transit system vehicle guideway constructed from modular elements and using magnetic levitation for suspension and propulsion vehicles |
| US20080231466A1 (en) * | 2007-03-19 | 2008-09-25 | Halliburton Energy Services, Inc. | Facilitating the communication of connectively dissimilar well servicing industry equipment via a universal connection device |
| GB2450698A (en) * | 2007-07-03 | 2009-01-07 | Mps Electronics Ltd | Networked monitoring apparatus locatable on a vehicle |
| US20090033494A1 (en) * | 2007-07-31 | 2009-02-05 | Symbol Technologies, Inc. | Vehicular mobile rf tags |
| US8461968B2 (en) | 2007-08-29 | 2013-06-11 | Hill-Rom Services, Inc. | Mattress for a hospital bed for use in a healthcare facility and management of same |
| US7868740B2 (en) | 2007-08-29 | 2011-01-11 | Hill-Rom Services, Inc. | Association of support surfaces and beds |
| US9483405B2 (en) | 2007-09-20 | 2016-11-01 | Sony Interactive Entertainment Inc. | Simplified run-time program translation for emulating complex processor pipelines |
| US8082160B2 (en) | 2007-10-26 | 2011-12-20 | Hill-Rom Services, Inc. | System and method for collection and communication of data from multiple patient care devices |
| US10759456B2 (en) | 2007-11-27 | 2020-09-01 | General Electric Company | Location determination system |
| US8154419B2 (en) * | 2007-12-14 | 2012-04-10 | Halliburton Energy Services Inc. | Oilfield area network communication system and method |
| US8046625B2 (en) | 2008-02-22 | 2011-10-25 | Hill-Rom Services, Inc. | Distributed fault tolerant architecture for a healthcare communication system |
| US8779924B2 (en) | 2010-02-19 | 2014-07-15 | Hill-Rom Services, Inc. | Nurse call system with additional status board |
| WO2011109659A1 (en) | 2010-03-03 | 2011-09-09 | Unimodal Systems, LLC | Modular electric generator for variable speed turbines |
| US8616274B2 (en) | 2010-05-07 | 2013-12-31 | Halliburton Energy Services, Inc. | System and method for remote wellbore servicing operations |
| US8433759B2 (en) | 2010-05-24 | 2013-04-30 | Sony Computer Entertainment America Llc | Direction-conscious information sharing |
| US9365223B2 (en) | 2010-08-23 | 2016-06-14 | Amsted Rail Company, Inc. | System and method for monitoring railcar performance |
| US8378854B1 (en) * | 2010-09-16 | 2013-02-19 | Glenview Properties LLC | Systems and methods for improved augmentation for GPS calculations |
| US9134426B1 (en) | 2010-09-16 | 2015-09-15 | United Parcel Service Of America, Inc. | Systems and methods for identifying attributes located along segments of a driving route |
| WO2012045182A1 (en) * | 2010-10-05 | 2012-04-12 | Die Schweizerische Post | Method of tracking a location of transported goods |
| EP2524852B1 (en) | 2011-05-17 | 2019-09-25 | Schweizerische Bundesbahnen SBB | Method and device for monitoring a section of a rail |
| US9002480B2 (en) * | 2011-10-13 | 2015-04-07 | Siemens Aktiengesellschaft | Method for operation of a control network, and a control network |
| US9411934B2 (en) | 2012-05-08 | 2016-08-09 | Hill-Rom Services, Inc. | In-room alarm configuration of nurse call system |
| US9282366B2 (en) | 2012-08-13 | 2016-03-08 | The Nielsen Company (Us), Llc | Methods and apparatus to communicate audience measurement information |
| US9314159B2 (en) | 2012-09-24 | 2016-04-19 | Physio-Control, Inc. | Patient monitoring device with remote alert |
| CN105431343B (en) | 2013-06-17 | 2018-07-10 | 国际电子机械公司 | Vehicles group monitors |
| US9830424B2 (en) | 2013-09-18 | 2017-11-28 | Hill-Rom Services, Inc. | Bed/room/patient association systems and methods |
| AU2014354639B2 (en) | 2013-11-27 | 2018-09-13 | Amsted Rail Company, Inc. | Train and rail yard management system |
| EP3086992A4 (en) | 2013-12-24 | 2018-12-12 | Amsted Rail Company, Inc. | System and method for detecting operational anomalies in train consists and railcars |
| US9606224B2 (en) * | 2014-01-14 | 2017-03-28 | Alstom Transport Technologies | Systems and methods for vehicle position detection |
| US9699499B2 (en) | 2014-04-30 | 2017-07-04 | The Nielsen Company (Us), Llc | Methods and apparatus to measure exposure to streaming media |
| US20160009303A1 (en) * | 2014-07-10 | 2016-01-14 | Mike Spahis | System and Method for Monitoring Mobile Vehicles |
| CN107614353B (en) | 2015-05-27 | 2020-03-17 | 阿母斯替德铁路公司 | System and method for establishing and managing train consist |
| US10113279B2 (en) | 2015-08-24 | 2018-10-30 | Off The Wall Products, Llc | Barrier systems with programmable light assembly |
| CN106476846B (en) * | 2016-10-20 | 2018-01-30 | 中车青岛四方车辆研究所有限公司 | Heavy Haul Freight Train organizing apparatus, grouping method and Electronically Controlled Pneumatic Brake Systems |
| US11123014B2 (en) | 2017-03-21 | 2021-09-21 | Stryker Corporation | Systems and methods for ambient energy powered physiological parameter monitoring |
| US11454728B2 (en) * | 2017-12-27 | 2022-09-27 | Westinghouse Air Brake Technologies Corporation | Real-time kinematics for a vehicle system |
| MX2020007708A (en) | 2018-01-24 | 2020-12-09 | Amsted Rail Co Inc | Discharge gate sensing method, system and assembly. |
| US11595256B2 (en) | 2018-04-17 | 2023-02-28 | Amsted Rail Company, Inc. | Autonomous optimization of intra-train communication network |
| CA3106016C (en) | 2018-07-12 | 2023-03-07 | Amsted Rail Company, Inc. | Brake monitoring systems for railcars |
| US10765952B2 (en) | 2018-09-21 | 2020-09-08 | Sony Interactive Entertainment LLC | System-level multiplayer matchmaking |
| US10695671B2 (en) | 2018-09-28 | 2020-06-30 | Sony Interactive Entertainment LLC | Establishing and managing multiplayer sessions |
| US11911325B2 (en) | 2019-02-26 | 2024-02-27 | Hill-Rom Services, Inc. | Bed interface for manual location |
| DE102019215194A1 (en) * | 2019-10-02 | 2021-04-08 | Robert Bosch Gmbh | Method, tracking device and evaluation device for recognizing an assignment of wagons in a train |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4651157A (en) * | 1985-05-07 | 1987-03-17 | Mets, Inc. | Security monitoring and tracking system |
| US4742357A (en) * | 1986-09-17 | 1988-05-03 | Rackley Ernie C | Stolen object location system |
| US4750197A (en) * | 1986-11-10 | 1988-06-07 | Denekamp Mark L | Integrated cargo security system |
| JPH0783366B2 (en) * | 1988-03-15 | 1995-09-06 | 富士通株式会社 | Building management system |
| US4897642A (en) * | 1988-10-14 | 1990-01-30 | Secura Corporation | Vehicle status monitor and management system employing satellite communication |
| US5602854A (en) * | 1991-05-13 | 1997-02-11 | Norand Corporation | Wireless personal local area network utilizing removable radio frequency modules with digital interfaces and idle sense communication protocol |
| WO1990013183A1 (en) * | 1989-04-18 | 1990-11-01 | Qualcomm Incorporated | Current carrier tractor-trailer data link |
| US5053964A (en) * | 1989-07-17 | 1991-10-01 | Utdc, Inc. | On-board integrated vehicle control and communication system |
| JP2887815B2 (en) * | 1990-08-08 | 1999-05-10 | アイシン精機株式会社 | Mobile station position monitoring system |
| US5225842A (en) * | 1991-05-09 | 1993-07-06 | Navsys Corporation | Vehicle tracking system employing global positioning system (gps) satellites |
| US5379224A (en) * | 1991-11-29 | 1995-01-03 | Navsys Corporation | GPS tracking system |
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1996
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- 1996-05-26 IL IL11842196A patent/IL118421A/en not_active IP Right Cessation
- 1996-05-29 EP EP96303807A patent/EP0748081A1/en not_active Withdrawn
- 1996-06-06 JP JP14379596A patent/JP3824280B2/en not_active Expired - Fee Related
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| JP3824280B2 (en) | 2006-09-20 |
| EP0748081A1 (en) | 1996-12-11 |
| CA2176883A1 (en) | 1996-12-08 |
| IL118421A0 (en) | 1996-09-12 |
| IL118421A (en) | 1999-11-30 |
| JPH09133758A (en) | 1997-05-20 |
| US5682139A (en) | 1997-10-28 |
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