Geofencing and route adherence in global positioning system with signals from fewer than three satellites

• US 7,492,315 B2
• Filed: 03/28/2007
• Issued: 02/17/2009
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: 2201028 Ontario Incorporated
• Original Assignee: Transcore Link Logistics Corporation (Roper Technologies, Inc.)
• Inventors: Verechtchiagine, Dimitri
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US11/692,665
• Publication Number:
  US 20080238769A1
• Time in Patent Office: 692 Days
• Field of Search: 342/357.06, 342/357.07, 342/357.08, 342/357.12, 342/357.13, 342/357.17, 702/152
• US Class Current: 342/357.33
• CPC Class Codes: G01S 19/42 Determining position

Abstract

Particular implementations are particularly useful in providing a system in which the hardware is more easily upgradable and new hardware functionality may be added without adding any new physical hardware. Through placement of an FPGA closely associated with the CPU of a personal computer, the FPGA may be reconfigured to act as new hardware. A system for installing new virtual hardware involves loading firmware into memory associated with the FPGA and reconfiguring the FPGA through a microcontroller. Particular implementations include universal ports associated with the FPGA into which adapter plugs can be placed to quickly adapt to any device that may be added through the virtual hardware use of the FPGA. Other implementations include high density connectors into which a plurality of ports of varying configurations may be plugged for connection of external electronic equipment through the FPGA.

Claims

1. A method for determining a minimum distance from a global positioning system receiver to a reference location, the method comprising:

(a) receiving at least one global positioning system signal from no more than two global positioning system satellites in the global positioning system receiver;

(b) determining, from the at least one global positioning system signal received in step (a), a set of possible locations at which the global positioning system can be located; and

(c) determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location

wherein, in step (a), said at least one global positioning system signal is received from two said global positioning system satellites and wherein step (b) comprises determining a solution plane approximating a solution surface comprising the set of possible locations near the reference location.

2. The method of claim 1, wherein step (c) comprises determining a minimum distance from the solution plane to the reference location.

3. The method of claim 1, wherein the global positioning system receiver is assumed to have a location constraint, and wherein the set of possible locations is determined from the solution plane and the location constraint.

4. The method of claim 3, wherein the location constraint is that the global positioning system receiver is assumed to be on a constraint surface, and wherein the set of possible locations is determined from an intersection of the constraint surface and the solution plane.

5. The method of claim 4, wherein the constraint surface is a horizontal plane.

6. A method for determining a minimum distance from a global positioning system receiver to a reference location, the method comprising:

(a) receiving at least one global positioning system signal from no more than two global positioning system satellites in the global positioning system receiver;

(b) determining, from the at least one global positioning system signal received in step (a), a set of possible locations at which the global positioning system can be located; and

(c) determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is determined from either a previously determined location of the global positioning system receiver or a previously determined solution surface.

7. A method for determining a minimum distance from a global positioning system receiver to a reference location, the method comprising:

(a) receiving at least one global positioning system signal from no more than two global positioning system satellites in the global positioning system receiver;

(b) determining, from the at least one global positioning system signal received in step (a), a set of possible locations at which the global positioning system can be located; and

(c) determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is a geofence anchor location.

8. The method of claim 7, wherein the geofence anchor location has a corresponding geofence radius, and further comprising comparing the minimum distance to the geofence radius to determine whether a geofence crossing even has taken place.

9. A method for determining a minimum distance from a global positioning system receiver to a reference location, the method comprising:

(a) receiving at least one global positioning system signal from no more than two global positioning system satellites in the global positioning system receiver;

(b) determining, from the at least one global positioning system signal received in step (a), a set of possible locations at which the global positioning system can be located; and

(c) determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is on a route, and further comprising using the minimum distance to determine whether the global positioning system receiver is following the route.

10. The method of claim 9, wherein the route is modeled as a plurality of line segments, and wherein the minimum distance is calculated to each of the line segments.

11. A global positioning system receiver for determining a minimum distance to a reference location, the global positioning system receiver comprising:

an antenna for receiving at least one global positioning system signal from no more than two global positioning system satellites; and

a processor, in communication with the antenna, for determining, from the at least one global positioning system signal received by the antenna, a set of possible locations at which the global positioning system can be located; and

for determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein said at least one global positioning system signal is received from two said global positioning system satellites and wherein the processor determines a solution plane approximating a solution surface comprising the set of possible locations near the reference location.

12. The global positioning system receiver of claim 11, wherein the processor determines a minimum distance from the solution plane to the reference location.

13. The global positioning system receiver of claim 11, wherein the global positioning system receiver is assumed to have a location constraint, and wherein the set of possible locations is determined from the solution plane and the location constraint.

14. The global positioning system receiver of claim 13, wherein the location constraint is that the global positioning system receiver is assumed to be on a constraint surface, and wherein the set of possible locations is determined from an intersection of the constraint surface and the solution plane.

15. The global positioning system receiver of claim 14, wherein the constraint surface is a horizontal plane.

16. A global positioning system receiver for determining a minimum distance to a reference location, the global positioning system receiver comprising:

an antenna for receiving at least one global positioning system signal from no more than two global positioning system satellites; and

a processor, in communication with the antenna, for determining, from the at least one global positioning system signal received by the antenna, a set of possible locations at which the global positioning system can be located; and

for determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is either a previously determined location of the global positioning system receiver or a previously determined solution surface.

17. A global positioning system receiver for determining a minimum distance to a reference location, the global positioning system receiver comprising:

an antenna for receiving at least one global positioning system signal from no more than two global positioning system satellites; and

a processor, in communication with the antenna, for determining, from the at least one global positioning system signal received by the antenna, a set of possible locations at which the global positioning system can be located; and

for determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is a geofence anchor location.

18. The global positioning system receiver of claim 17, wherein the geofence anchor location has a corresponding geofence radius, and further comprising comparing the minimum distance to the geofence radius to determine whether a geofence crossing even has taken place.

19. A global positioning system receiver for determining a minimum distance to a reference location, the global positioning system receiver comprising:

an antenna for receiving at least one global positioning system signal from no more than two global positioning system satellites; and

a processor, in communication with the antenna, for determining, from the at least one global positioning system signal received by the antenna, a set of possible locations at which the global positioning system can be located; and

for determining a minimum distance from the set of possible locations to the reference location as the minimum distance from the global positioning system receiver to the reference location, wherein the reference location is on a route, and further comprising using the minimum distance to determine whether the global positioning system receiver is following the route.

20. The global positioning system receiver of claim 19, wherein the route is modeled as a plurality of line segments, and wherein the minimum distance is calculated to each of the line segments.