Anti-spoofing in a satellite navigation system
View Patent ↗Embodiments are generally directed to anti-spoofing techniques for satellite navigation systems. In general, the anti-spoofing techniques use codeless or semi-codeless tracking of encrypted satellite signals to generate measurements that can be used to perform consistency checks to received non-encrypted signals. The consistency checks will detect if the non-encrypted signal is a genuine satellite signal or a spoofing signal.
1. A method comprising:
receiving, at a receiver, non-encrypted signals and encrypted signals from a plurality of satellites;
determining location information for the receiver from the non-encrypted signals to generate non-encrypted location information;
executing a semi-codeless technique to determine location information for the receiver from the encrypted signals to generate encrypted location information; and
determining, based on the encrypted location information, a difference between the encrypted location information and the non-encrypted location information.
2. The method of claim 1 , further comprising:
comparing the difference between the encrypted location information and the non-encrypted location information to a predetermined threshold,
wherein a difference that is greater than the threshold indicates that the non-encrypted location information is not accurate.
3. The method of claim 1 , wherein determining location information for the receiver from the non-encrypted signals comprises:
determining position, velocity, and time measurements (PVT) measurements for the receiver using the non-encrypted signals.
4. The method of claim 3 , wherein determining location information for the receiver from the encrypted signals comprises:
determining PVT measurements for the receiver from a carrier signal associated with the encrypted signals.
5. The method of claim 1 , wherein the receiver is a Global Positioning System (GPS) receiver, the non-encrypted signals are Coarse/Acquisition (C/A) code signals, and the encrypted signals are Precision (P) code signals forming P(Y) signals.
6. The method of claim 1 , wherein the receiver is a timing receiver.
7. An apparatus, comprising:
one or more antennas;
a receiver coupled to the one or more antennas configured to:
receive, via the one or antennas, non-encrypted signals and encrypted signals from a plurality of satellites;
determine location information for the receiver from the non-encrypted signals to generate non-encrypted location information;
execute a semi-codeless technique to determine location information for the receiver from the encrypted signals to generate encrypted location information; and
determine, based on the encrypted location information, a difference between the encrypted location information and the non-encrypted location information.
8. The apparatus of claim 7 , wherein the receiver is further configured to:
compare the difference between the encrypted location information and the non-encrypted location information to a predetermined threshold,
wherein a difference that is greater than the threshold indicates that the non-encrypted location information is not accurate.
9. The apparatus of claim 7 , wherein to determine location information for the receiver from the non-encrypted signals, the receiver is configured to:
determine position, velocity, and time measurements (PVT) measurements for the receiver using the non-encrypted signals.
10. The apparatus of claim 9 , wherein to determine location information for the receiver from the encrypted signals, the receiver is configured to:
determine PVT measurements for the receiver from a carrier signal associated with the encrypted signals.
11. The apparatus of claim 7 , wherein the receiver is a Global Positioning System (GPS) receiver, the non-encrypted signals are Coarse/Acquisition (C/A) code signals, and the encrypted signals are Precision (P) code signals forming P(Y) signals.
12. The apparatus of claim 7 , wherein the receiver is a timing receiver.
13. One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:
receive at a receiver, non-encrypted signals and encrypted signals from a plurality of satellites;
determine location information for the receiver from the non-encrypted signals to generate non-encrypted location information;
execute a semi-codeless technique to determine location information for the receiver from the encrypted signals to generate encrypted location information; and
determine, based on the encrypted location information, a difference between the encrypted location information and the non-encrypted location information.
14. The non-transitory computer readable storage media of claim 13 , further comprising instructions operable to:
compare the difference between the encrypted location information and the non-encrypted location information to a predetermined threshold,
wherein a difference that is greater than the threshold indicates that the non-encrypted location information is not accurate.
15. The non-transitory computer readable storage media of claim 13 , wherein the instructions operable to determine location information for the receiver from the non-encrypted signals comprise instructions operable to:
determine position, velocity, and time measurements (PVT) measurements for the receiver using the non-encrypted signals.
16. The non-transitory computer readable storage media of claim 15 , wherein the instructions operable to determine location information for the receiver from the encrypted signals comprise instructions operable to:
determine PVT measurements for the receiver from a carrier signal associated with the encrypted signals.