Method for determining stationary locomotive location in a railyard

• US 6,405,127 B1
• Filed: 09/15/2000
• Issued: 06/11/2002
• Est. Priority Date: 09/15/2000
• Status: Expired due to Term

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: General Electric Company
• Inventors: Doner, John R.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US09/663,112
• Time in Patent Office: 634 Days
• Field of Search: 701/200, 701/207, 340/7.21, 340/7.28, 340/988, 340/989, 340/993, 340/825.49, 346/2.R, 346/122.R, 342/357.08, 342/358, 342/357.06
• US Class Current: 701/207
• CPC Class Codes: G01S 19/07 providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile

Abstract

A system for determining a locomotive within a railyard includes a base station, a base station receiver that receives location data pertaining to the base station location, a mobile receiver that receives location data pertaining to the location of locomotive, and a computer. The mobile receiver utilizes data from a group of satellites that are a subset of the satellite constellation used to obtain base station location data. The computer tracks base station location data and computes a position error for the base station. The computer applies the error to a locomotive estimated position resulting in an accurate locomotive location.

Claims

1. A method for determining the location of an object using a system, the system including a base station having a known fixed position, a base station receiver configured to receive location data from a first set of satellites, a mobile receiver coupled with the object configured to receive location data from a second set of satellites, with the second set of satellites being a subset of and thus fewer in number than the first set of satellites, and a computer configured to determine the location of the object from the location data, said method comprising the steps of:

utilizing the base station receiver to receive base station location data from the first set of satellites;

storing the base station location data from the first set of satellites using the computer;

utilizing the mobile receiver to receive object location data from the second set of satellites;

utilizing the computer and the stored base station location data from the first set of satellites to determine base station location data with respect to the second set of satellites, and a base station position estimate;

calculating a positional error in the base station position estimate relative to the known fixed position of the base station; and

determining a calculated location of the object using the positional error and the object location data.

2. A method in accordance with claim 1 wherein the computer further configured to electronically store data, said step of utilizing the base station receiver to receive base station location data from the first set of satellites further comprises the steps of:

receiving the base station location data continuously at a predetermined sampling interval;

communicating the base station location data to the computer; and

storing the base station location data in the computer.

3. A method in accordance with claim 2 wherein the mobile receiver further configured to compute an average fixed location of the object and communicate with the computer, said step of utilizing the mobile receiver to receive object location data from the second set of satellites further comprising the steps of:

receiving the object location data continuously at a predetermined sampling interval;

averaging the object location data to determine an averaged fixed position of the object; and

communicating the averaged fixed position to the computer.

4. A method in accordance with claim 3 further comprising the step of identifying the satellites that comprise the second set of satellites.

5. A method in accordance with claim 4 wherein said step of identifying the satellites further comprises the step of communicating the averaged fixed position to the computer using a data stream format comprising

6. A method in accordance with claim 5 wherein said step of utilizing the stored base station location data from the first set of satellites and the computer to determine base station location data with respect to the second set of satellites further comprises the steps of parsing data from the first set of location data stored in the computer correlating to the same satellites and time interval identified in the data stream.

7. A method in accordance with claim 1 wherein said step of calculating a positional error further comprises the steps of:

determining the base station location based on the third set of location data; and

determining a disparity between a known fixed location of the base station and a base station location determined using the third set of location data.

8. A method in accordance with claim 1 wherein said step of determining the location of the object using the positional error further comprises the steps of:

determining an average fixed position of the object based on the second set of location data;

modifying the position error to account for an offset between a sampling time of the first set of data, and a sampling time of the second set of data using the equation; and

adjusting the average fixed position of the object using the modified position error.

9. A method in accordance with claim 8 wherein said step of modifying the position error to account for an offset between a sampling time of the first set of location data, and a sampling time of the second set of location data further comprises the step of modifying the latitude position error, μ

_i, by ${\mathrm{\mu <br><br>}}_i^{\mathrm{\prime <br><br>}}={\mathrm{\mu <br><br>}}_i+\left(\frac{t_i^{\mathrm{\prime <br><br>}}-t_i}{t_{i+1}-t_i}\right)<br><br>\left({\mathrm{\mu <br><br>}}_{i+1}-{\mathrm{\mu <br><br>}}_i\right)$

and modifying the longitude positional error, ν

_i, by $v_i^{\mathrm{\prime <br><br>}}=v_i+\left(\frac{t_i^{\mathrm{\prime <br><br>}}-t_i}{t_{i+1}-t_i}\right)<br><br>\left(v_{i+1}-v_i\right)$

for i=0,1,2, . . . N

wherein t is the time of data collection, and N is the number of samples to be averaged.

10. A method in accordance with claim 8 wherein the step of adjusting the average fixed position of the object using the position error further comprises the step of adjusting the average latitude fixed position, θ

_l, by ${\mathrm{\theta <br><br>}}_L={\mathrm{\theta <br><br>}}_L^{\left(t_0\right)}-\frac{1}{N}<br><br>\underset{i=0}{\overset{N-1}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\mu <br><br>}}_i^{\mathrm{\prime <br><br>}}$

and adjusting the average longitude fixed position, φ

, by ${\mathrm{\phi <br><br>}}_L={\mathrm{\phi <br><br>}}_L^{\left(t_0\right)}-\frac{1}{N}<br><br>\text{\hspace{1em}<br><br>}<br><br>\underset{i=0}{\overset{N-1}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>v_i^{\mathrm{\prime <br><br>}}$

wherein μ

′

_i is the modified latitude positional error, ν

′

_i is the modified longitude positional error, and N is the number of sample to be averaged.

11. A system for determining a location of an object at rest on a path that lays in close proximity to at least one other path, said system comprising:

a base station having a known fixed position;

a base station receiver configured to receive base station location data from a first set of satellites;

a mobile receiver coupled to the object, said mobile receiver configured to receive object location data from a second set of satellites; and

a computer configured to electronically store data including the base station location data from the first set of satellites, communicate with said base station receiver and said mobile receiver, and determine base station location data with respect to the second set of satellites using the stored base station location data from the first set of satellites.

12. A system in accordance with claim 11 wherein said base station receiver further configured to:

receive the base station location data from the first set of satellites continuously and at a predetermined sampling interval; and

communicate the base station location data from the first set of satellites to said computer.

13. A system in accordance with claim 11 wherein said computer further configured to electronically store the base station location data from the first set of satellites.

14. A system in accordance with claim 11 wherein said mobile receiver further configured to:

receive the object location data from the second set of satellites continuously and at a predetermined sampling interval; and

compute an averaged fixed position of the object using the object location data from the second set of satellites.

15. A system in accordance with claim 14 wherein said mobile receiver further configured to communicate with said computer using a data stream comprising the averaged fixed position, and information identifying the second set of satellites.

16. A system in accordance with claim 15 wherein said data stream configured to use a format comprising

17. A system in accordance with claim 16 wherein the base station location data with respect to the second set of satellites comprises parsed data from the based station location data from the first set of satellites correlating to the same satellites and time interval identified in the data stream.

18. A system in accordance with claim 11 wherein said computer further configured to compute a base station location based on the base station location data with respect to the second set of satellites.

19. A system in accordance with claim 18 wherein said computer further configured to compute a position error comprising the disparity between the base station location based on the base station location data with respect to the second set of satellites and the known fixed location of said base station.

20. A system in accordance with claim 19 wherein said computer further configured to modify the position error to account for an offset between a sampling time of the base station location data with respect to the second set of satellites and a second sampling time of the object location data from the second set of satellites.

21. A system in accordance with claim 20 wherein said computer further configured to modify said latitude position error, μ

_i, using ${\mathrm{\mu <br><br>}}_i^{\mathrm{\prime <br><br>}}={\mathrm{\mu <br><br>}}_i+\left(\frac{t_i^{\mathrm{\prime <br><br>}}-t_i}{t_{i+1}-t_i}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\left({\mathrm{\mu <br><br>}}_{i+1}-{\mathrm{\mu <br><br>}}_i\right)$

and modify said longitude position error, ν

_i, using $v_i^{\mathrm{\prime <br><br>}}=v_i+\left(\frac{t_i^{\mathrm{\prime <br><br>}}-t_i}{t_{i+1}-t_i}\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(v_{i+1}-v_i\right)$

for i=0,1,2, . . . N

wherein t is the time of data collection, and N is the number of samples to be averaged.

22. A system in accordance with claim 20 wherein said computer further configured to compute the location of the object by adjusting the average fixed position using the modified position error.

23. A system in accordance with claim 22 wherein said computer further configured to compute the latitude, θ

_l, of the object using ${\mathrm{\theta <br><br>}}_L={\mathrm{\theta <br><br>}}_L^{\left(t_0\right)}-\frac{1}{N}<br><br>\text{\hspace{1em}<br><br>}<br><br>\underset{i=0}{\overset{N-1}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\mathrm{\mu <br><br>}}_i^{\mathrm{\prime <br><br>}}$

and compute the longitude, φ

, of the object using ${\mathrm{\theta <br><br>}}_L={\mathrm{\theta <br><br>}}_L^{\left(t_0\right)}-\frac{1}{N}<br><br>\text{\hspace{1em}<br><br>}<br><br>\underset{i=0}{\overset{N-1}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>v_i^{\mathrm{\prime <br><br>}}$

wherein μ

′

_i is the modified latitude positional error, ν

′

_i is the modified longitude positional error, and N is the number of sample to be averaged.

24. A system in accordance with claim 11 wherein the object comprises a locomotive.

25. A method for determining the location of an object using a system, the system including a base station, a base station receiver configured to receive location data from a first set of satellites, a computer, and a mobile receiver coupled with the object configured to receive location data from a second set of satellites, with the second set of satellites being a subset of and thus fewer in number than the first set of satellites, said method comprising:

utilizing the base station receiver to receive base station location data from the first set of satellites;

storing the base station location data from the first set of satellites using the computer; and

utilizing the mobile receiver to receive object location data from the second set of satellites.

26. A method in accordance with claim 25 further comprising:

utilizing the stored base station location data from the first set of satellites and the computer to determine base station location data with respect to the second set of satellites; and

utilizing the base station location data with respect to the second set of satellites and the computer to determine a base station position estimate.

27. A method in accordance with claim 26, wherein the base station has a known fixed position and said method further comprises calculating a positional error in the base station position estimate relative to the known fixed position of the base station.

28. A method in accordance with claim 27 further comprising determining a calculated location of the object using the positional error and the object location data.