Method and system for detecting interference for global positioning systems

• US RE41,382 E1
• Filed: 05/20/2009
• Issued: 06/22/2010
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: General Dynamics C4 Systems Incorporated (General Dynamics Corporation)
• Original Assignee: General Dynamics C4 Systems Incorporated (General Dynamics Corporation)
• Inventors: Hepner, Clinton Charles, Yee, David Moon, York, Jeffrey Dean
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US12/469,142
• Time in Patent Office: 398 Days
• Field of Search: 342/357.02, 342/357.06, 342/357.09, 342/357.12, 342/358
• US Class Current: 342/357.23
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G01S 5/0215 Interference
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal

Abstract

A method and system for detecting GPS interference is disclosed. In one exemplary embodiment, a method for detecting interference in a Global Positioning System comprises the steps of receiving at least one satellite signal from one or more satellites in a Global Positioning System; identifying a noise floor value from the at least one satellite signal; identifying an interference signal based on the noise floor value; determining an interference value for the interference signal from the noise floor value wherein a level of the noise floor value corresponds to a level of interference; and providing the interference value to at least one user for informing the user of the interference signal.

Claims

1. A method for detecting interference in a Global Positioning System, the method comprising the steps of:

receiving at least one satellite signal from one or more satellites in a Global Positioning System;

measuring a noise floor value in a frequency band of the at least one satellite signal;

identifying an interference signal based on the noise floor value wherein the interference signal is determined by a comparison between the noise floor value from the at least one satellite signal and a predetermined acceptable range;

determining an interference value for the interference signal from the noise floor value wherein a level of the noise floor value corresponds to a level of interference;

wherein the comparison between the noise floor value and the predetermined acceptable range determines a corresponding interference value for the interference signal;

wherein if the noise floor value is within the predetermined acceptable range, the interference value is set at a predetermined low interference value;

wherein if the noise floor value is outside the predetermined acceptable range, the noise floor interference value is set at a predetermined high interference value; and

providing the interference value to at least one user for informing the user of the interference signal.

2. The method of claim 1, wherein the interference value comprises a percentage between 0% and 100% representing a percentage of interference of the interference signal on maintaining a GPS signal lock.

3. The method of claim 1, wherein the interference value represents an average interference value for the one or more satellites.

4. The method of claim 1, wherein the interference signal comprises one or more of a jamming signal and a spoofing signal.

5. The method of claim 1, further comprising the step of:

providing the interference value to one or more recipients other than the at least one user for informing the one or more recipients of the interference signal via radio transmission.

6. The method of claim 5, wherein the one or more recipients comprise one or more of a ground unit, an airborne unit, an equipment unit, and a vehicle sensor unit.

7. The method of claim 1, further comprising the steps of:

determining an interference strength of the interference signal; and

providing the interference strength of the interference signal to the at least one user.

8. The method of claim 1, further comprising the steps of:

determining an interference direction of the interference signal; and

providing the interference direction of the interference signal to the at least one user.

9. The method of claim 1, wherein the step of receiving is performed at a search and rescue radio.

10. The method of claim 1, wherein the step of providing the interference value further comprises the step of:

displaying the interference value to the at least one user via a user interface.

11. The method of claim 10, further comprising the step of:

displaying a graphical representation of the interference value.

12. The method of claim 1, further comprising the step of:

triggering the user to switch to an alternative mode of position location, in response to being informed of the interference signal.

13. The method of claim 12, wherein the alternative mode of operation comprises distance measuring equipment (DME) mode.

14. The method of claim 1, further comprising the step of:

triggering the user to block the interference signal, in response to being informed of the interference signal.

15. The method of claim 1, further comprising the steps of:

transmitting the interference value to a central unit wherein the central unit receives a plurality of interference values from a plurality of other users; and

determining a source location of the interfering signal based at least in part on the interference value from the user and the one or more interference values from the plurality of other users.

16. A system for detecting interference in a Global Positioning System, the system comprising:

a receiving module for receiving at least one satellite signal from one or more satellites in a Global Positioning System;

a noise floor module for measuring a noise floor value in a frequency band of the at least one satellite signal;

a detection module for identifying an interference signal based on the noise floor value wherein the interference signal is determined by a comparison between the noise floor value from the at least one satellite signal and a predetermined acceptable range and determining an interference value for the interference signal from the noise floor value wherein a level of the noise floor value corresponds to a level of interference;

wherein the comparison between the noise floor value and the predetermined acceptable range determines a corresponding interference value for the interference signal;

wherein if the noise floor value is within the predetermined acceptable range, the interference value is set at a predetermined low interference value;

wherein if the noise floor value is outside the predetermined acceptable range, the noise floor interference value is set at a predetermined high interference value; and

a notification module for providing the interference value to at least one user for informing the user of the interference signal.

17. The system of claim 16, wherein the interference value comprises a percentage between 0% and 100% representing a percentage of interference of the interference signal on maintaining a GPS signal lock.

18. The system of claim 16, wherein the interference value represents an average interference value for the one or more satellites.

19. The system of claim 16, wherein the interference signal comprises one or more of a jamming signal and a spoofing signal.

20. The system of claim 16, wherein the interference value is provided to one or more recipients other than the at least one user for informing the one or more recipients of the interference signal via radio transmission.

21. The system of claim 20, wherein the one or more recipients comprise one or more of a ground unit, an airborne unit, an equipment unit, and a vehicle sensor unit.

22. The system of claim 16, wherein the detection module further determines an interference strength of the interference signal;

and the notification module further provides the interference strength of the interference signal to the at least one user.

23. The system of claim 16, wherein the detection module further determines an interference direction of the interference signal;

and the notification module further provides the interference direction of the interference signal to the at least one user.

24. The system of claim 16, wherein the system comprises a search and rescue radio.

25. The system of claim 16, further comprises a user display for displaying the interference value to the at least one user via a user interface.

26. The system of claim 25, wherein the user display displays a graphical representation of the interference value.

27. The system of claim 16, wherein the user switches to an alternative mode of position location, in response to being informed of the interference signal.

28. The system of claim 27, wherein the alternative mode of operation comprises distance measuring equipment (DME) mode.

29. The system of claim 16, wherein the user blocks the interference signal, in response to being informed of the interference signal.

30. The system of claim 16, wherein the interference value is transmitted to a central unit wherein the central unit receives a plurality of interference values from a plurality of other users;

and a source location of the interfering signal is determined based at least in part on the interference value from the user and the one or more interference values from the plurality of other users.

31. An article of manufacture for detecting interference in a Global Positioning System, the article of manufacture comprising:

at least one processor readable carrier; and

instructions carried on the at least one carrier;

wherein the instructions are configured to be readable from the at least one carrier by at least one processor and thereby cause the at least one processor to operate so as to;

receive at least one satellite signal from one or more satellites in a Global Positioning System;

measure a noise floor value in a frequency band of the at least one satellite signal;

identify an interference signal based on the noise floor value wherein the interference signal is determined by a comparison between the noise floor value from the at least one satellite signal and a predetermined acceptable range;

determine an interference value for the interference signal from the noise floor value wherein a level of the noise floor value corresponds to a level of interference;

wherein the comparison between the noise floor value and the predetermined acceptable range determines a corresponding interference value for the interference signal;

wherein if the noise floor value is within the predetermined acceptable range, the interference value is set at a predetermined low interference value;

wherein if the noise floor value is outside the predetermined acceptable range, the noise floor interference value is set at a predetermined high interference value; and

provide the interference value to at least one user for informing the user of the interference signal.