Estimating the location of a wireless terminal based on assisted GPS and pattern matching

• US 8,965,393 B2
• Filed: 05/22/2006
• Issued: 02/24/2015
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Polaris Wireless Incorporated
• Original Assignee: Polaris Wireless Incorporated
• Inventors: Bhattacharya, Tarun Kumar
• Primary Examiner(s): Vu, Michael T
• Application Number:
  US11/419,640
• Publication Number:
  US 20060240841A1
• Time in Patent Office: 3,200 Days
• Field of Search: 4554561-4566, 432/458, 432/357.06, 342/457, 342/450, 342/453, 342/357.31
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/17 Emergency applications
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A method of using a non-GPS-derived technique to estimate the location of an Assisted-GPS-enabled wireless terminal for the purposes of generating location-specific assistance data for the wireless terminal is disclosed. The wireless terminal then uses the assistance data to acquire and process one or more GPS signals and to derive information that is probative of the wireless terminal'"'"'s location. The GPS-derived location information is then combined with non-GPS-derived location to form an estimate of the location of the wireless terminal that is better than can be derived from either alone. This combination of GPS-derived and non-GPS techniques is particularly useful when the wireless terminal can only acquire one or two GPS signals because it is not possible to determine the location of the wireless terminal with only two GPS signals alone.

Claims

1. A process comprising:

generating a first assistance data for a satellite signal at a first location that is serviced by a base station;

generating a second assistance data for the satellite signal at a second location that is serviced by the base station;

generating a first non-GPS-derived estimate of the location of a wireless terminal that is serviced by the base station; and

transmitting the first assistance data to the wireless terminal when the first non-GPS-derived estimate of the location of the wireless terminal is closer to the first location than the second location, and transmitting the second assistance data to the wireless terminal when the first non-GPS-derived estimate of the location of the wireless terminal is closer to the second location than the first location;

wherein the first non-GPS-derived estimate of the location of the wireless terminal is based on comparing a first measurement of a trait of a first signal to a map that correlates locations with predicted values of the trait.

2. The process of claim 1 wherein the first non-GPS-derived estimate of the location of the wireless terminal is more accurate than an estimate based on cell ID alone.

3. The process of claim 1 further comprising receiving a second estimate of the location of the wireless terminal from the wireless terminal based on the satellite signal.

4. The process of claim 3 further comprising generating a third estimate of the location of the wireless terminal based on the first measurement and the second estimate of the location of the wireless terminal.

5. The process of claim 3 further comprising generating a third estimate of the location of the wireless terminal based on the second estimate of the location of the wireless terminal and a second measurement of the trait of the first signal.

6. The process of claim 1 further comprising receiving ranging data from the wireless terminal based on the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the ranging data.

7. The process of claim 1 further comprising receiving ranging data from the wireless terminal based on the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the ranging data and the first measurement.

8. The process of claim 1 further comprising receiving ranging data from the wireless terminal based on the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the ranging data and a second measurement of the trait of the first signal.

9. The process of claim 1 further comprising receiving a partially-processed satellite signal from the wireless terminal based on the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the partially-processed satellite signal.

10. The process of claim 1 further comprising receiving a partially-processed satellite signal from the wireless terminal based on the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the partially-processed satellite signal and the first measurement.

11. The process of claim 1 further comprising receiving a partially-processed satellite signal from the wireless terminal based the satellite signal;

and

generating a second estimate of the location of the wireless terminal based on the partially-processed satellite signal and a second measurement of the trait of the first signal.

12. An apparatus comprising:

a first server comprising a first processor for;

(i) generating a first assistance data for a satellite signal at a first location that is serviced by a base station, and

(ii) generating a second assistance data for the satellite signal at a second location that is serviced by the base station;

a second server comprising a second processor for generating a first non-GPS-derived estimate of the location of a wireless terminal that is serviced by the base station; and

a transmitter for transmitting the first assistance data when the first non-GPS-derived estimate of the location of the wireless terminal is closer to the first location than the second location, and transmitting the second assistance data when the first non-GPS-derived estimate of the location of the wireless terminal is closer to the second location than the first location;

wherein the first non-GPS-derived estimate of the location of the wireless terminal is based on comparing a first measurement of a trait of a first signal to a map that correlates locations with predicted values of the trait.

13. The apparatus of claim 12 wherein the first server and the second server are the same server.

14. The apparatus of claim 13 wherein the wireless terminal generates a second estimate of its own location based on the satellite signal and transmits the second estimate.

15. The apparatus of claim 14 wherein the second server generates a third estimate of the location of the wireless terminal based on the first measurement and the second estimate of the location of the wireless terminal.

16. The apparatus of claim 14 wherein the second server generates a third estimate of the location of the wireless terminal based on the second estimate of the location of the wireless terminal and a second measurement of the trait of the first signal.

17. The apparatus of claim 13 wherein the second server:

(i) receives ranging data from the wireless terminal based on the satellite signal; and

(ii) generates a second estimate of the location of the wireless terminal based on the ranging data and the first measurement.

18. The apparatus of claim 13 wherein the second server:

(i) receives a partially-processed satellite signal from the wireless terminal based on the satellite signal; and

(ii) generates a second estimate of the location of the wireless terminal based on the partially-processed satellite signal and the first measurement.

19. The apparatus of claim 12 wherein the first processor and the second processor are the same processor.

20. The apparatus of claim 12 wherein the second server:

(i) receives ranging data from the wireless terminal based on the satellite signal; and

(ii) generates a second estimate of the location of the wireless terminal based on the ranging data.

21. The apparatus of claim 12 wherein the second server:

(i) receives a partially-processed satellite signal from the wireless terminal based on the satellite signal; and

(ii) generates a second estimate of the location of the wireless terminal based on the partially-processed satellite signal.