SYSTEM AND METHOD FOR SERVER SIDE DETECTION OF FALSIFIED SATELLITE MEASUREMENTS

• US 20100127928A1
• Filed: 11/24/2008
• Published: 05/27/2010
• Est. Priority Date: 11/24/2008
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Harper, Neil, Thomson, Martin
• Granted Patent: US 8,035,557 B2
• Time in Patent Office: Days
• US Class Current: 342/357.450
• CPC Class Codes: G01S 19/215 issues related to spoofing

Abstract

A system and method for determining whether a wireless device has transmitted one or more forged satellite measurements. An estimated location of the wireless device may be determined as a function of information from a cellular network. Acquisition assistance data may be determined for a first set of satellites as a function of the estimated location, the assistance data including an uncertainty window. If measured code phase information in the satellite measurements substantially correlates to the uncertainty window, then the wireless device may be transmitting forged satellite measurements.

Claims

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;

(b) determining acquisition assistance data for a first set of satellites as a function of the estimated location, the assistance data including an uncertainty window; and

(c) identifying one or more satellite measurements received from the wireless device as forged if measured code phase information in the measurements substantially correlates to the uncertainty window.

2. The method of claim 1 wherein the uncertainty window is a code phase uncertainty window.

3. The method of claim 1 wherein the step of identifying further comprises:

(d) for ones of the first set of satellites from which the wireless device receives a signal, comparing relative code phase information; and

(e) identifying a forged satellite measurement if a difference between the relative code phase information is substantially outside the uncertainty window.

4. The method of claim 3 wherein the relative code phase information is a difference between code phase information reported by the wireless device and code phase information determined by a location information server.

5. The method of claim 11 wherein the estimated location is determined as a function of coarse acquisition (“

C/A”

) code phase shift information.

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

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

8. 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.

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

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

10. The method of claim 9 wherein the second set of satellites is a subset of the first set of satellites.

11. The method of claim 9 wherein the second set of satellites is mutually exclusive of the first set of satellites.

12. 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.

13. The method of claim 1 wherein the satellites are a part of a Global Navigation Satellite System (“

GNSS”

).

14. The method of claim 13 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.

15. 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;

(b) determining acquisition assistance data for a first set of satellites as a function of the estimated location;

(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) identifying one or more forged satellite measurements if a difference between measured code phase information for ones of the first 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.

16. The method of claim 15 wherein the measured code phase information is coarse acquisition (“

C/A”

) code phase shift information.

17. The method of claim 15 wherein the estimated location is determined as a function of Doppler information.

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

19. The method of claim 15 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.

20. The method of claim 15 further comprising the step of:

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

21. The method of claim 20 wherein the second set of satellites is a subset of the first set of satellites.

22. The method of claim 20 wherein the second set of satellites is mutually exclusive of the first set of satellites.

23. The method of claim 15 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.

24. The method of claim 15 wherein the satellites are a part of a Global Navigation Satellite System (“

GNSS”

).

25. The method of claim 24 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.

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

(a) circuitry for determining an estimated location of the wireless device;

(b) circuitry for determining acquisition assistance data for a set of satellites as a function of the estimated location, the assistance data including an uncertainty window; and

(c) circuitry for identifying the wireless device as transmitting one or more forged satellite measurements if code phase information received from the wireless device substantially correlates to the uncertainty window.

27. The system of claim 26 wherein the circuitry for identifying further comprises circuitry for comparing the received code phase information to code phase information in the determined acquisition assistance data.

28. The system of claim 26 wherein the code phase information is coarse acquisition (“

C/A”

) code phase shift information.

29. The system of claim 26 wherein the estimated location is determined as a function of Doppler information.

30. The system of claim 26 wherein the estimated location is determined as a function of signals provided by a cellular network.

31. The system of claim 26 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.

32. The system of claim 26 wherein the satellites are a part of a Global Navigation Satellite System (“

GNSS”

).

33. The system of claim 32 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.