PARKING GARAGE ENVIRONMENT DETECTION AND EHPE DETERMINATION FOR VEHICULAR NAVIGATION

• US 20150142309A1
• Filed: 11/19/2013
• Published: 05/21/2015
• Est. Priority Date: 11/19/2013
• Status: Active Grant

• Current Assignee: General Motors LLC (General Motors Company)
• Original Assignee: General Motors LLC (General Motors Company)
• Inventors: Hay, Curtis L., Sun, Debo
• Granted Patent: US 9,644,970 B2
• Time in Patent Office: Days
• US Class Current: 701/469
• CPC Class Codes: B60W 10/00 Conjoint control of vehicle sub-units of different type or different function for propulsion of purely electrically-propelled vehicles with power supplied within the vehicle B60L50/00 - B60L58/00
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

Implementations of the present invention contemplate obtaining a more accurate estimated horizontal position error (EHPE) under conditions in which the telematics unit of a vehicle cannot receive GNSS signals. In particular, the invention contemplates determining that a vehicle is entering a parking garage and obtaining a more accurate estimated horizontal position error (EHPE) of the vehicle in the parking garage when GNSS signals are unavailable.

Claims

1. A method, implemented at a telematics unit of a vehicle, for calculating the estimated horizontal position error (EHPE) of a position of a vehicle provided by a dead reckoning (DR) engine, the method comprising:

determining that the vehicle is operating within a parking garage, wherein determining that the vehicle is operating within a parking garage triggers the use of a parking garage mode by a DR engine of the telematics unit; and

determining the EHPE of the vehicle according to the parking garage mode of the DR engine.

2. The method of claim 1, wherein determining that the vehicle is operating within a parking garage comprises analyzing data received from a GNSS.

3. The method of claim 1, wherein determining that the vehicle is operating within a parking garage comprises analyzing heading change characteristics of vehicular movement.

4. The method of claim 3, wherein analyzing heading change characteristics comprises comparing a heading change accumulation calculated at a first time with a heading change accumulation calculated at a second time.

5. The method of claim 3 wherein analyzing heading change characteristics of vehicular movement comprises:

determining that S_hd(k+L)−

S_hd(k)>

180°

, wherein S_hd(k) is the heading change accumulation at time k, and S_hd(k+L) is the heading change accumulation at time k+L.

6. The method of claim 1, wherein determining the EHPE of the vehicle according to the parking garage mode of the DR engine comprises multiplying the distance traveled by the estimated heading error (EHE).

7. The method of claim 1, wherein determining the EHPE of the vehicle according to the parking garage mode of the DR engine comprises:

selecting an equation to use for calculating the EHPE of the vehicle; and

evaluating the selected equation;

wherein selecting the equation to use for calculating the EHPE of the vehicle comprises;

specifying an EHPE calculation factor relation, an EHPE calculation factor delta relation, an offset detecting threshold, an EHPE calculation limiting threshold, and an accumulated heading change consideration threshold;

calculating a value for the EHPE calculation factor using the EHPE calculation factor delta relation, the offset detecting threshold, the EHPE calculation factor limiting threshold, and the accumulated heading change consideration threshold; and

selecting an equation to use for calculating the EHPE of the vehicle based on the calculated value of the EHPE calculation factor.

8. The method of claim 7, wherein the EHPE calculation factor delta relation specifies that the EHPE calculation factor delta is equal to a first value if the accumulated heading change is less than the accumulated heading change consideration threshold and equal to a relation accounting for the accumulated heading change if the accumulated heading change is greater than the accumulated heading change consideration threshold.

9. The method of claim 1, wherein determining the EHPE of the vehicle according to the parking garage mode of the DR engine comprises:

determining the EHPE(k)=EHPE(k−

1)+hE(k)·

Δ

d(k) if C_EHPE(N−

1)≦

1; and

determining that

10. The method of claim 9, wherein T₂ is any value greater than 2 and T₃ is any value greater than 0.5.

11. A computer readable medium having stored thereon a set of computer executable instructions for calculating the estimated horizontal position error (EHPE) of a position of a vehicle provided by a dead reckoning (DR) engine, the set of instructions comprising instructions for:

determining that the vehicle is operating within a parking garage, wherein determining that the vehicle is operating within a parking garage triggers the use of a parking garage mode by a DR engine of the telematics unit; and

determining the EHPE of the vehicle according to the parking garage mode of the DR engine.

12. The computer readable medium of claim 11, wherein determining that the vehicle is operating within a parking garage comprises analyzing data received from a GNSS.

13. The computer readable medium of claim 11, wherein determining that he vehicle is operating within a parking garage comprises analyzing heading change characteristics of vehicular movement.

14. The computer readable medium of claim 13, wherein analyzing heading change characteristics of vehicular movement comprises:

determining that S_hd(k−

L)−

S_hd(k)>

180°

, wherein S_hd(k) is the heading change accumulation at time k, and S_hd(k+L) is the heading change accumulation at time k+L.

15. The computer readable medium of claim 11, wherein determining, the EHPE of the vehicle according to the parking garage mode of the DR engine comprises multiplying the distance traveled by the estimated heading error (EHE).

16. The computer readable medium of claim 15, wherein determining the EHPE of the vehicle according to the parking garage mode of the DR engine comprises:

determining that EHPE(k)=EHPE(k−

1)+hE(k)·

Δ

d(k) if C_EHPE(N−

1)≦

1; and

determining that

17. The computer readable medium of claim 16, wherein T₂ is any value greater than 2 and T₃ is any value greater than 0.5.

18. A telematics unit configured to receive GNSS signals and to determine the position of a vehicle through dead reckoning (DR) techniques when it is unable to receive GNSS signals, the telematics unit comprising:

a processor configured to determine that the vehicle is operating within a parking garage and further configured to execute a parking garage DR mode upon determining that the vehicle is operating within the parking garage wherein the parking garage DR mode determines an estimated horizontal position error (EHPE) of the position of the vehicle.

19. The telematics unit of claim 18, wherein determining that the vehicle is operating within a parking garage comprises analyzing data received from a GNSS.

20. The telematics unit of claim 18, wherein determining that the vehicle is operating within a parking garage comprises analyzing heading change characteristics of vehicular movement.