Method of improving a vehicle emergency call network

• US 7,705,775 B2
• Filed: 12/30/2005
• Issued: 04/27/2010
• Est. Priority Date: 12/30/2005
• Status: Expired due to Fees

• Current Assignee: General Motors LLC (General Motors Company)
• Original Assignee: General Motors LLC (General Motors Company)
• Inventors: Patil, Abhijit D., Madhavan, Sethu K., Aloi, Daniel N., Yasan, Eray
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/323,502
• Publication Number:
  US 20070152877A1
• Time in Patent Office: 1,579 Days
• Field of Search: 342/357.02, 342/342.09, 342/357.09, 455/404.2, 701/200, 701/201, 701/205, 701/208
• US Class Current: 342/357.31
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

A method of improving a vehicle emergency call network used during an enhanced 911 call, which is especially useful in environments having degraded GPS signals. The present method utilizes an independent position enhancement algorithm, such as a dead reckoning algorithm, and converts the output of that algorithm into a compatible format compatible with a position determining entity (PDE). Some independent position enhancement algorithms return output in the form of position information (typically, two- or three-dimensional coordinates), however, most PDEs only accept information in the form of pseudo-ranges. Thus, the present method provides a technique in which the advantages of an independent position enhancement algorithm are enjoyed, yet a compatible output is sent to the PDE.

Claims

1. A method for improving a vehicle emergency call network, comprising the steps:

(a) utilizing an independent position enhancement algorithm to determine enhanced position information for a vehicle that is in the form of three-dimensional coordinates;

(b) converting said enhanced position information for the vehicle from three-dimensional coordinates to enhanced pseudo-range information that is in the form of pseudo-ranges; and

(c) sending said enhanced pseudo-range information to a position determining entity (PDE).

2. The method of claim 1, wherein said independent position enhancement algorithm of step (a) utilizes data provided by at least one of a gyroscope and a wheel speed sensor.

3. The method of claim 2, wherein said independent position enhancement algorithm of step (a) is a dead-reckoning algorithm.

4. The method of claim 1, wherein step (b) further includes determining whether or not ephemeris data is valid.

5. The method of claim 1, wherein step (b) further includes identifying a plurality of visible satellites that would have been visible to a GPS receiver unit at a particular time, assuming that nothing was obstructing their transmission.

6. The method of claim 5, wherein step (b) further includes determining a health status for each of said plurality of visible satellites.

7. The method of claim 1, wherein step (b) further includes purposely inserting a set of errors in said enhanced pseudo-range information in order to offset subsequent error corrections made by said PDE.

8. The method of claim 7, wherein said set of errors includes at least one of the following:

i) clock synchronization errors, ii) atmospheric transmission delay errors, and iii) Earth rotational errors.

9. The method of claim 1, wherein said enhanced pseudo-range information of step (c) is sent to said PDE in an electronic message that conforms with an IS-801 format.

13. The method of claim 1, wherein step (b) further includes determining a Doppler frequency f.

10. A method for improving a vehicle emergency call network, comprising the steps of:

(a) utilizing a GPS receiver unit to receive GPS information from at least one satellite;

(b) utilizing said GPS information and an independent position enhancement algorithm to determine enhanced position information for a vehicle that is generally in the form of coordinates;

(c) converting said enhanced position information for the vehicle into enhanced pseudo-range information that has a set of errors purposely inserted therein; and

(d) sending said enhanced pseudo-range information with said set of errors to a position determining entity (PDE) in an electronic message that conforms with an IS-801 format.

11. A method for improving a vehicle emergency call network, comprising the steps:

(a) utilizing an independent position enhancement algorithm to determine enhanced position information for a vehicle that is in the form of three-dimensional coordinates;

(b) converting said enhanced position information for the vehicle from three-dimensional coordinates to enhanced pseudo-range information that is in the form of pseudo-ranges by utilizing the following equation;

PRⁱ⁼c(TOTⁱ⁻

TOR)+ε

ⁱ

wherein, PRⁱ is an enhanced pseudo-range;

c is the speed of light;

TOTⁱ is a time of transmission;

TOR is a time of reception; and

ε

ⁱ is an error due to the Earth'"'"'s rotation;

(c) purposely inserting a set of errors in the enhanced pseudo-range information in order to offset subsequent error corrections made by a position determining entity (PDE), wherein the set of errors includes at least one of the following;

i) clock synchronization errors, ii) atmospheric transmission delay errors, and iii) Earth rotational errors; and

(d) sending said enhanced pseudo-range information to said PDE.

12. The method of claim 11, wherein step (b) further includes utilizing the following equation: