System and method for server side detection of falsified satellite measurements

1. A method for determining whether a wireless device has transmitted one or more forged satellite measurements, comprising the steps of:

(a) determining an estimated location of the wireless device, the estimated location including a predetermined uncertainty area;

(b) determining acquisition assistance data for a first set of satellites as a function of the estimated location by a location determining system, the assistance data including a code phase uncertainty window corresponding to said predetermined uncertainty area;

(c) for ones of the first set of satellites from which the wireless device receives a signal, comparing code phase information measured by the device to code phase information in the determined acquisition assistance data; and

(d) at the location determining system identifying one or more forged satellite measurements if a difference between said measured code phase information for said ones of the first set of satellites and said code phase information in the determined acquisition assistance data for the same ones of satellites is greater than a predetermined threshold, said predetermined threshold being defined by said code phase uncertainty window.

2. The method of claim 1 wherein the measured code phase information is coarse acquisition (“C/A”) code phase shift information.

3. The method of claim 1 wherein the estimated location is determined as a function of Doppler information.

4. The method of claim 1 wherein the estimated location is determined as a function of signals provided by a cellular network.

5. The method of claim 1 further comprising the step of determining another estimated location of the wireless device from signals received from a second set of satellites, the second set excluding a satellite having a forged measurement.

6. The method of claim 1 further comprising the step of:

(e) repeating steps (a) through (d) using signals received from a second set of satellites.

7. The method of claim 6 wherein the second set of satellites is a subset of the first set of satellites.

8. The method of claim 6 wherein the second set of satellites is mutually exclusive of the first set of satellites.

9. The method of claim 1 wherein the wireless device is selected from the group consisting of: cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

10. The method of claim 1 wherein the satellites are a part of a Global Navigation Satellite System (“GNSS”).

11. The method of claim 10 wherein the GNSS is selected from the group consisting of: a Global Positioning System (“GPS”), Galileo system, GLONASS system, Quasi-Zenith Satellite System (“QZSS”), Beidou satellite system, Compass satellite system, and combinations thereof.

12. A system for determining whether a wireless device has transmitted one or more forged satellite measurements, comprising:

first circuitry configured to determine an estimated location of the wireless device, the estimated location including a predetermined uncertainty area;

second circuitry configured to determine acquisition assistance data for a first set of satellites as a function of the estimated location, the assistance data including a code phase uncertainty window corresponding to said predetermined uncertainty area;

third circuitry configured to compare code phase information measured by the device to code phase information in the determined acquisition assistance data for ones of the first set of satellites from which the wireless device receives a signal; and

fourth circuitry configured to identify one or more forged satellite measurements if a difference between said measured code phase information for said ones of the first set of satellites and said code phase information in the determined acquisition assistance data for the same ones of satellites is greater than a predetermined threshold, said predetermined threshold being defined by said code phase uncertainty window.

13. The system of claim 12 wherein the measured code phase information is coarse acquisition (“C/A”) code phase shift information.

14. The system of claim 12 wherein the estimated location is determined as a function of Doppler information.

15. The system of claim 12 wherein the estimated location is determined as a function of signals provided by a cellular network.

16. The system of claim 12 further comprising circuitry for determining another estimated location of the wireless device from signals received from a second set of satellites, the second set excluding a satellite having a forged measurement.

17. The system of claim 12 further comprising:

fifth circuitry for determining an estimated location of the wireless device;

sixth circuitry for determining acquisition assistance data for a second set of satellites as a function of the estimated location;

seventh circuitry for comparing code phase information measured by the device to code phase information in the determined acquisition assistance data for ones of the second set of satellites from which the wireless device receives a signal; and

eighth circuitry for identifying one or more forged satellite measurements if a difference between measured code phase information for ones of the second set of satellites and code phase information in the determined acquisition assistance data for the same ones of satellites is greater than a predetermined threshold.

18. The system of claim 17 wherein the second set of satellites is a subset of the first set of satellites.

19. The system of claim 17 wherein the second set of satellites is mutually exclusive of the first set of satellites.

20. The system of claim 17 wherein said sixth circuitry is the same as said second circuitry, said seventh circuitry is the same as said third circuitry, and said eighth circuitry is the same as said fourth circuitry.

21. The system of claim 12 wherein the wireless device is selected from the group consisting of: cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

22. The system of claim 12 wherein the satellites are a part of a Global Navigation Satellite System (“GNSS”).

23. The system of claim 22 wherein the GNSS is selected from the group consisting of: a Global Positioning System (“GPS”), Galileo system, GLONASS system, Quasi-Zenith Satellite System (“QZSS”), Beidou satellite system, Compass satellite system, and combinations thereof.