Signal inconsistency detection of spoofing

• US 20070247362A1
• Filed: 04/06/2007
• Published: 10/25/2007
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Victor Strachan
• Inventors: Strachan, Victor
• Granted Patent: US 7,450,060 B2
• Time in Patent Office: Days
• US Class Current: 342/357.290
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H04K 2203/22 for communication related to vehicles
• CPC Class Codes: H04K 3/22 including jamming detection and monitoring
• CPC Class Codes: H04K 3/255 based on redundancy of transmitted data, transmission path or transmitting source
• CPC Class Codes: H04K 3/65 using deceptive jamming or spoofing, e.g. transmission of false signals for premature triggering of RCIED, for forced connection or disconnection to/from a network or for generation of dummy target signal
• CPC Class Codes: H04K 3/90 related to allowing or preventing navigation or positioning, e.g. GPS

Abstract

Methods and apparatus relating to signal inconsistency detection of spoofing (SIDS), i.e. the use of inconsistencies in signals received at a plurality of points in space to detect spoofing.

Claims

1-21. -21. (canceled)

22. A method of detecting spoofing using one or more radio receivers, at least one antenna, and an inertial reference system, comprising:

computing velocity changes of the at least one antenna;

estimating a difference between navigation measurements to be received by the antenna from a navigation system at least two time periods based on the computed velocity changes; and

comparing the estimated difference to an actual difference between navigation measurements derived from signals received at at least two time periods to determine whether the received signal is a spoofing signal.

23. The method of claim 22 wherein the velocity changes of the at least one antenna are computed using the inertial reference system.

24. The method of claim 23 wherein the inertial reference system computes the velocity changes of the at least one antenna by evaluating dynamics of a lever arm coupled between the inertial reference system and the at least one antenna.

25. The method of claim 22 wherein the velocity changes of the at least one antenna are based on a priori knowledge of lever arm dynamics.

26. The method of claim 22 further comprising correcting the inertial reference system only if the comparing step yields a value less than a predetermined threshold.

27. The method of claim 26 wherein the estimating step relies on a priori knowledge of position of the navigation system, and wherein the predetermined threshold is based on statistical error in the a priori knowledge.

28. The method of claim 26 wherein the predetermined threshold is based on a desired level of certainty.

29. The method of claim 26 wherein the correcting step comprises updating current position data of the inertial reference system only if the comparing step yields a value less than the predetermined threshold.

30. The method of claim 22 wherein the estimating step relies on a priori knowledge of position of the navigation system.

31. A method of validating a navigation signal using a radio receiver having an antenna and an inertial reference system, comprising:

obtaining a first navigation measurement from a navigation signal with the antenna in a first position;

obtaining a second navigation measurement from the navigation signal with the antenna in a second position;

calculating a difference between the first and second measurements;

estimating a difference between a first navigation measurement to be obtained with the antenna in a first position and a second navigation measurement to be obtained with the antenna in a second position;

comparing the estimated difference to the calculated difference; and

determining validity of the navigation signal based on the comparison.

32. The method of claim 31 wherein the estimating step comprises the inertial reference system estimating a change in position of the antenna based on antenna velocity.

33. The method of claim 32 wherein the inertial reference system derives the antenna velocity by evaluating dynamics of a lever arm coupled between the inertial reference system and the antenna.

34. The method of claim 31 wherein the estimating step comprises estimating a change in position of the antenna based on a prior knowledge of antenna dynamics.

35. The method of claim 31 wherein the estimating step relies on a priori knowledge of position of the navigation system.

36. The method of claim 31 further comprising determining the navigation signal as valid if a result of the comparing step yields a value less than a predetermined threshold.

37. The method of claim 36 further comprising correcting the inertial reference system if the navigation signal is valid.

38. The method of claim 37 wherein the correcting step comprises updating current position data of the inertial reference system if the navigation signal is valid.

39. The method of claim 36 wherein the estimating step relies on a priori knowledge of position of the navigation system, and wherein the predetermined threshold is based on statistical error in the a priori knowledge.

40. The method of claim 36 wherein the predetermined threshold is based on a desired level of certainty.