Method and apparatus to automatically generate a train manifest

• US 5,902,341 A
• Filed: 10/30/1996
• Issued: 05/11/1999
• Est. Priority Date: 10/30/1996
• Status: Expired due to Term

• Current Assignee: ViaSat Incorporated
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Wilson, John Bryan
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): WYCKOFF, TIMOTHY R
• Application Number:
  US08/741,250
• Time in Patent Office: 923 Days
• Field of Search: 701/19, 701/20, 246/122 R, 246/124, 246/167 R, 246/6, 246/3, 246/169 R, 340/825.49, 340/825.54, 340/988, 340/989, 342/357, 342/457
• US Class Current: 342/357.34
• CPC Class Codes: B61L 15/0027 Radio-based, e.g. using GSM-R
• CPC Class Codes: B61L 15/0072 On-board train data handling
• CPC Class Codes: B61L 2205/04 Satellite based navigation systems, e.g. global positioning system [GPS]
• CPC Class Codes: B61L 25/021 Measuring and recording of train speed
• CPC Class Codes: B61L 25/025 Absolute localisation, e.g. providing geodetic coordinates
• CPC Class Codes: B61L 27/40 Handling position reports or trackside vehicle data
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 19/51 Relative positioning

Abstract

A system located in a region to determine information about an unknown car relative to a moving train includes first and second satellite navigation receivers, first and second transceivers and first and second controllers. The moving train includes a first car, and the region includes the moving train and the unknown car. The region is defined by points at which radio communication with the first car is possible. The first satellite navigation receiver, located in the first car, provides first location data, and the second satellite navigation receiver, located in the unknown car, provides second location data. The first transceiver is located in the first car, and the second transceiver is located in the unknown car. The first controller, located in the first car, reads the first location data from the first satellite receiver at a first time and sends via the first transceiver a first request to the second transceiver at the first time. The second controller, located in the unknown car and responsive to the first request received via the second transceiver, reads the second location data from the second satellite receiver and sends via the second transceiver a first response to the first transceiver, the first response including the second location data, wherein the first controller receives via the first transceiver the response and calculates a first distance from a first difference between the first and second location data. Alternatively, the first controller polls the region for unknown cars. An unknown car responds with it identification number. The first controller has a Doppler receiver to determine whether the unknown and responding car is moving with respect to the first controller. From the Doppler indications of all responding cars, the first controller determines a train manifest, and then transmits the manifest and equipment status via satellite to a central station.

Claims

1. In a region that includes a moving train and at least one unconnected car, the moving train including a first car, the region being defined by points at which radio communication with the first car is possible, a method to determine membership of an unknown car in the moving train, the method comprising steps of:

determining a first relative position of the unknown car relative to the first car at a first time by using a satellite navigation system;

determining a second relative position of the unknown car relative to the first car at a second time by using the satellite navigation system;

calculating a displacement distance from a difference between the first relative position and the second relative position; and

declaring the unknown car to be a member of the moving train when the displacement distance is substantially zero.

2. The method of claim 1, wherein the step of determining a first relative position includes:

determining at the first time a position of the first car by using the satellite navigation system;

sending at the first time a first position request from the first car to the unknown car;

determining responsive to the first position request a position of the unknown car by using the satellite navigation system;

receiving a first position response from the unknown car at the first car, the first position response including the position of the unknown car as determined in response to the first position request; and

forming the first relative position by subtracting the position of the first car from the position of the unknown car.

3. The method of claim 2, wherein the step of determining a first relative position further includes:

determining at the second time a position of the first car by using the satellite navigation system;

sending at the second time a second position request from the first car to the unknown car;

determining responsive to the position request a position of the unknown car by using the satellite navigation system;

receiving a second position response from the unknown car at the first car, the second position response including the position of the unknown car as determined in response to the second position request; and

forming the second relative position by subtracting the position of the first car from the position of the unknown car.

4. The method of claim 2, further including a step of sending the first position response from the unknown car to the first car so that the first position response includes an identification number corresponding to the unknown car.

5. The method of claim 1 further including a step of building a manifest, wherein:

the steps of determining first and second relative positions includes determining an identification number assigned to the unknown car; and

the step of building a manifest includes (i) repeating the steps of determining first and second relative positions, calculating and declaring and (ii) listing the identification numbers of cars declared to be a member of the moving train.

6. The method of claim 5, further including a step of sending a message to a central station via a radio link, wherein the step of determining a first relative position includes determining a position of the first car at the first time, the message including the manifest and the position of the first car at the first time.

7. A system located in a region to determine information about an unknown car relative to a moving train, the moving train including a first car, the region including the moving train and the unknown car, the region being defined by points at which radio communication with the first car is possible, the system comprising:

means for determining a first relative position of the unknown car relative to the first car at a first time by using a satellite navigation system;

means for determining a second relative position of the unknown car relative to the first car at a second time by using the satellite navigation system;

means for calculating a displacement distance from a difference between the first relative position and the second relative position; and

means for declaring the unknown car to be a member of the moving train when the displacement distance is substantially zero.

8. The system of claim 7, wherein the means for determining a first relative position includes:

means for determining at the first time a position of the first car by using the satellite navigation system;

means for sending at the first time a first position request from the first car to the unknown car;

means for determining responsive to the first position request a position of the unknown car by using the satellite navigation system;

means for receiving a first position response from the unknown car at the first car, the first position response including the position of the unknown car as determined in response to the first position request; and

means for forming the first relative position by subtracting the position of the first car from the position of the unknown car.

9. The system of claim 8, further including means for sending the first position response from the unknown car to the first car so that the first position response includes an identification number corresponding to the unknown car.

10. The system of claim 8, wherein the means for determining a first relative position further includes:

means for determining at the second time a position of the first car by using the satellite navigation system;

means for sending at the second time a second position request from the first car to the unknown car;

means for determining responsive to the position request a position of the unknown car by using the satellite navigation system;

means for receiving a second position response from the unknown car at the first car, the second position response including the position of the unknown car as determined in response to the second position request; and

means for forming the second relative position by subtracting the position of the first car from the position of the unknown car.

11. A system located in a region to determine information about an unknown car relative to a moving train, the moving train including a first car, the region including the moving train and the unknown car, the region being defined by points at which radio communication with the first car possible, the system comprising:

a first satellite navigation receiver located in the first car to provide first location data;

a second satellite navigation receiver located in the unknown car to provide second location data;

first and second transceivers, the first transceiver being located in the first car, the second transceiver being located in the unknown car;

a first controller located in the first car, the first controller reading the first location data from the first satellite receiver at a first time and sending via the first transceiver a first request to the second transceiver at the first time;

a second controller located in the unknown car, the second controller responsive to the first request received via the second transceiver reading the second location data from the second satellite receiver and sending via the second transceiver a first response to the first transceiver, the first response including the second location data,

wherein the first controller receives via the first transceiver the response and calculates a first distance from a first difference between the first and second location data.

12. The system of claim 11, wherein the first controller further includes repeat circuitry, the repeat circuitry including:

a timer to define a second time after the second time;

a control element to initiate reading second location data from the first satellite receiver at the second time and sending a second request at the second time, the first controller receiving a second response and calculating a second distance; and

a calculator to determine a displacement distance as a difference between the first and second distances, the calculator declaring the unknown car to be a member of the moving train when the displacement distance is substantially zero.