Method of determining the position of a vehicle moving along a guideway

• US 9,085,310 B2
• Filed: 05/25/2011
• Issued: 07/21/2015
• Est. Priority Date: 05/25/2011
• Status: Active Grant

• Current Assignee: Ground Transportation Systems Canada Incorporated
• Original Assignee: Thales Canada Incorporated (Thales SA)
• Inventors: McKillican, Boyd, Kanner, Abe
• Primary Examiner(s): Kuhfuss, Zachary
• Application Number:
  US13/115,425
• Publication Number:
  US 20120299777A1
• Time in Patent Office: 1,518 Days
• Field of Search: 246/122.R, 701/19
• US Class Current: 1/1
• CPC Class Codes: B61L 25/025 Absolute localisation, e.g. providing geodetic coordinates
• CPC Class Codes: B61L 3/125 using short-range radio transmission
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 5/02695 Constraining the position to lie on a curve or surface
• CPC Class Codes: G01S 5/08 Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A method of determining the position of a vehicle moving along a guideway is disclosed wherein signals from groups of transponders located beside the guideway are detected as the vehicle moves along the guideway to create a footprint in the time domain corresponding to the time the vehicle is in communication with that transponder. The transponders of each group are spaced a known distance apart from each other. An estimate of the position of the moving vehicle is computed by matching the point in the time domain that bears the same geometric relationship to the footprints corresponding to the transponders of the group to a point in the spatial domain that bears a known geometric relationship with the transponders of each group.

Claims

1. A method of determining a position of a vehicle moving along a guideway, comprising:

detecting signals from each of a plurality of localized groups of transponders located beside the guideway as the vehicle moves along the guideway, each localized group being located at a detection location, the individual transponders within each said localized group being spaced a known distance apart from each other, said localized groups being spaced substantially further apart from each other than the individual transponders within each said localized group, wherein as the vehicle passes a current said detection location, the signals from each transponder within the localized group at the current detection location create a footprint in a time domain corresponding to a time the vehicle is in communication with that transponder;

identifying a point in a spatial domain between the transponders that bears a known geometric relationship with the transponders of each localized group; and

computing an estimate of the position of the moving vehicle by matching a point in the time domain that bears the same geometric relationship to the footprints of the transponders of the localized group at the current detection location as the point in the spatial domain bears with the transponders of the localized group at the current detection location.

2. A method as claimed in claim 1, wherein each said localized group comprises a pair of said transponders, and the position of the vehicle is computed by determining the midpoint between the footprints corresponding to the transponders in the pair forming the localized group at the current detection location.

3. A method as claimed in claim 1, the distances between the transponders of each localized group are constant.

4. A method as claimed in claim 1, wherein the distances between the transponders of each localized group vary and are stored in a database.

5. A method as claimed in claim 1, wherein the transponders of each localized group are spaced apart by less than ten meters.

6. A method as claimed in claim 1, wherein the point in the time domain is determined by both rising and falling edges of the footprints.

7. A guideway-mounted system for determining a position of a vehicle moving along a guideway wherein transponders are located beside a guideway such that a detector on the moving vehicle generates signals that create a footprint in a time domain corresponding to a time the vehicle is in communication with that transponder, and wherein the transponders are arranged in a plurality of localized groups spaced a known distance apart, and the localized groups are spaced substantially further apart from each other than the individual transponders within each said localized group, each localized group being located at a detection location, whereby as a vehicle moves along the guideway past a current said detection location the vehicle is able to compute an estimate of position by matching a point in a spatial domain between the transponders that bears a known geometric relationship with the transponders of the localized group at the current detection location with a point in the time domain that bears the same geometric relationship to the footprints corresponding to the transponders of the localized group at the current detection location.

8. A system as claimed in claim 7, wherein each localized group of transponders comprises a pair of said transponders.

9. A system as claimed in claim 7, the distances between the transponders of each localized group are constant.

10. A system as claimed in claim 7, wherein the distances between the transponders of each localized group vary.

11. A system as claimed in claim 7, wherein the transponders of each localized group are spaced apart by less than ten meters.

12. A vehicle-mounted system for determining a position of a vehicle moving along a guideway, comprising:

a detector for detecting signals from a plurality of localized groups of transponders located beside the guideway as the vehicle moves along the guideway, the transponders of each localized group being spaced a known distance apart from each other, and said localized groups being spaced substantially further apart from each other than the individual transponders within each said localized group, each localized group being located at a detection location, and wherein as the vehicle passes a current said detection location the signals from each transponder in the localized group at the current detection location create a footprint in a time domain corresponding to the time the vehicle is in communication with that transponder; and

a processor for computing an estimate of the position of the moving vehicle by matching a point in the time domain that bears the same geometric relationship to the footprints corresponding to the transponders of the localized group at the current detection location to a point in the spatial domain between the transponders that bears a known geometric relationship with the transponders of the localized group at the current detection location.

13. A vehicle-mounted system as claimed in claim 12, wherein the point in the time domain is the midpoint between the footprints.

14. A vehicle-mounted system as claimed in claim 12, further comprising a database storing the distances between the transponders of each localized group.

15. A system for determining a position of a vehicle moving along a guideway, comprising:

localized groups of transponders located beside the guideway, the transponders of each localized group being spaced a known distance apart from each other, and said localized groups being spaced substantially further apart from each other than the individual transponders within each said localized group, each localized group being located at a detection location;

a detector on the vehicle for detecting signals from the transponders as the vehicle moves along the guideway, and wherein as the vehicles passes a current detection location the signals from each transponder in the localized group at the current detection location create a footprint in a time domain corresponding to a time the vehicle is in communication with that transponder; and

;

a processor on the vehicle for computing an estimate of the position of the moving vehicle by matching a point in the time domain that bears the same geometric relationship to the footprints corresponding to the transponders of the localized group at the current detection location to a point in the spatial domain between the individual transponders that bears a known geometric relationship with the transponders of the localized group at the current detection location.

16. A system as claimed in claim 15, wherein each said localized group comprises a pair of transponders and the position of the vehicle is computed by determining the midpoint between the footprints corresponding to the transponders of the pair forming the localized group at the current detection location.

17. A system as claimed in claim 15, wherein the distances between the transponders of each localized group are constant.

18. A system as claimed in claim 15, wherein the distances between the transponders of each localized group vary and are stored in a database.

19. A system as claimed in claim 15, wherein the transponders of each localized group are spaced apart by less than ten meters.