Method and system for proximity detection and location determination

• US 6,218,961 B1
• Filed: 02/20/1998
• Issued: 04/17/2001
• Est. Priority Date: 10/23/1996
• Status: Expired due to Term

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: GE Harris Railway Electronics, LLC (GE Aerospace)
• Inventors: Gross, Eric, Easterling, Scott, Guarino, Anthony J., Gottfried, Michael S., Reinhart, Leonard R., Peek, Ernest, Zahm, Charles L.
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US09/027,256
• Time in Patent Office: 1,152 Days
• Field of Search: 340/903, 340/902, 340/905, 340/425.5, 340/566, 340/539, 340/991, 340/988, 340/990, 246/3, 246/122.R, 246/121, 246/166, 246/166.1, 246/167.R, 246/125, 246/124, 246/126, 701/19, 701/117, 342/455
• US Class Current: 340/903
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B61L 2205/04 Satellite based navigation systems, e.g. global positioning system [GPS]
• CPC Class Codes: B61L 23/34 for indicating the distance between vehicles or trains by the transmission of signals therebetween
• CPC Class Codes: B61L 25/025 Absolute localisation, e.g. providing geodetic coordinates
• CPC Class Codes: B61L 25/026 Relative localisation, e.g. using odometer
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks
• CPC Class Codes: G01S 2205/002 for traffic control, mobile tracking, guidance, surveillance or anti-collision
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236

Abstract

A system and method for preventing collisions between vehicles, such as railway vehicles, by exchanging data regarding track position of the vehicles. By use of an on-board track database, the system provides an indication of the distance between vehicles based not on line-of-sight but on track distance. Additionally, a system and method for accurately determining location of railway vehicles without the use of a network of trackside indicators. The disclosed system uses a gyro, position indicator, and a satellite position determination along with a track database to maintain highly accurate estimates of measurement errors and track position.

Claims

1. An on-board vehicle proximity detector comprising:

(a) means for determining the geographic position of a vehicle carrying the proximity detector, said vehicle traveling along a predetermined track layout;

(b) a database of track parameters of the track layout on which the vehicle is traveling;

(c) means responsive to said database and said geographic position determining means for determining the track position of the vehicle;

(d) means for receiving from other vehicles wireless signals including the track positions of the other vehicles;

(e) means responsive to said track position determining means and said receiving means for determining the distance along said track layout between the vehicle carrying the proximity detector and each of the other vehicles from which track positions are received; and

,

(f) means responsive to said distance along the track determining means for initiating an alarm if the determined distance is less than a safe amount.

2. The proximity detector of claim 1 including means for transmitting the track position of the vehicle carrying the proximity detector via a wireless link.

3. The proximity detector of claim 1 further comprising:

(g) means for automatically initiating a braking action if a crew of the vehicle fails to respond appropriately to the alarm.

4. The proximity detector of claim 1 further comprising:

(h) means for automatically disabling said means for automatically initiating a braking action at predetermined locations along said track layout.

5. The proximity detector of claim 1 further comprising:

(i) means for automatically disabling said means for automatically initiating a braking action whenever the speed of the vehicle is below a threshold level.

6. The proximity detector of claim 2 wherein the transmission of the track position is performed periodically at plural periodic rates, one of said periodic rates being used when the vehicle is at some portions of the track layout and others of the periodic rates being used when the vehicle is at other portions of the track layout.

7. The proximity detector of claim 1 wherein said database includes a table of successive geographic boxes, each of said boxes being associated with a different position along said track layout.

8. The proximity detector of claim 7 wherein some of said geographic boxes represent geographic areas having a first size and others of said geographic boxes represent geographic areas having a second size, said first size being different from said second size.

9. The proximity detector of claim 7 wherein each of said boxes is defined by a line of longitude and a line of latitude.

10. The proximity detector of claim 7 wherein the size of some of said geographic boxes is determined, at least in part, from the area of uncertainty associated with said geographic position.

14. The proximity detector of claim 1 wherein said safe amount is a predetermined distance.

15. The proximity detector of claim 1 wherein said safe amount is determined, at least in part, from the expected braking distance of said vehicle, said expected braking distance including an assessment of the grade of the track.

16. The proximity detector of claim 2 wherein the means for transmitting and the means for receiving comprise a digital RF communication processor.

17. The proximity detector of claim 1 where the means for determining the distance along said track and the means for initiating an alarm comprise a proximity detection computer.

11. A method for determining the location of a railway vehicle along a track in a track layout having plural parallel tracks for at least a portion thereof and having switches between some of said parallel tracks, said railway vehicle comprising a satellite positioning system, a gyro, a linear position estimating device and a track database, comprising the steps of:

(a) providing an approximate location of the vehicle from the satellite positioning system;

(b) determining from the track database all track paths within a specified area of uncertainty from said approximate location;

(c) establishing a Kalman filter for each determined track path, each of said filters monitoring the difference between the vehicle'"'"'s heading as measured by said gyro and heading data stored in the track database;

(d) monitoring at each Kalman filter as the vehicle moves along the track for residual differences in the heading state;

(e) upon a residual difference exceeding a specified threshold value, eliminating the associated track path as one of the track paths; and

,

(f) upon the reduction of the number of track paths to one, declaring the associate path to be the path along which the vehicle is travelling.

12. A proximity detection system for a vehicle having an identification associated therewith and travelling along a predetermined track layout comprising:

(a) a satellite positioning system which provides signals indicating the geographic location of the railway vehicle;

(b) a track database which includes data regarding the track used by the railway vehicle, said track including plural track segments, and said data including the geographic position of track segments and the heading of track segments;

(c) tachometer measuring the revolutions of one or more of the wheels of the vehicle for providing the position of the vehicle along the track;

(d) a gyro for providing the change in heading of the vehicle; and

,

(e) filter which receives the signals indicating the geographic location, the position of the vehicle along the track, the heading of the vehicle and the track database to provide an estimate of the error in said geographic position the error in said heading and the error in said position of the vehicle along the track to determine the track position of the vehicle;

(f) means for transmitting via a wireless link said identification and said track position;

(g) means for receiving wireless signals from other vehicles, said wireless signals including the identifications and track positions of said other vehicles;

(h) means for determining the distance along said track layout between said vehicle and said other vehicles; and

(i) means for initiating an alarm if the determined distance is less than a predetermined amount.

13. The proximity detection system of claim 12 further comprising:

(f) means for automatically initiating a braking action if a crew of the vehicle fails to respond appropriately to the alarm; and

,

(g) means for automatically disabling said means for automatically initiating a braking action at predetermined locations along said track layout.

18. A railway vehicle location determination system comprising:

(a) a satellite positioning system which provides signals indicating the geographic location of the railway vehicle;

(b) a track database which includes data regarding a track layout used by the railway vehicle, said track layout including plural track segments each having an associated mileage point, and said data including a geographic box associated with each mileage point;

(c) a computer which compares the geographic location of the railway vehicle with said geographic boxes to select the geographic box in which the geographic location of the vehicle is located; and

(d) a display for displaying the mileage point associated with the selected geographic box.

19. The location determination system of claim 18 wherein the size of said geographic boxes is based on said track layout and the uncertainty of the measurement of the location.

20. The location determination system of claim 18 wherein the size of said geographic boxes are defined by longitude and latitude.

21. A railway vehicle location determination system comprising:

(a) a satellite positioning system which provides signals indicating the approximate geographic location of the railway vehicle;

(b) a track database which includes data regarding the track used by the railway vehicle, said track including all track paths within a specified region of uncertainty for said approximate position, and said data including the geographic position of track segments and the heading of track segments;

(c) a tachometer measuring the revolutions of one or more of the wheels of the vehicle for providing the position of the vehicle along the track;

(d) a gyro for providing the change in heading of the vehicle;

(e) a Kalman filter for each track path within the specified region of uncertainty which receives the signals indicating the geographic location, the position of the vehicle along the track, the heading of the vehicle and the track database to provide an estimate of the error in said geographic position, the error in said heading and the error in said position of the vehicle along the track; and

(f) a turn out processor for comparing the turn rate and the heading from said gyro with the turn rate and heading from said track database to determine which of said track paths the vehicle is traveling.