Cross-correlations of unknown encrypted signals between civilian GNSS receivers are used to detect spoofing known open-source signals. This type of detection is the strongest known defense against spoofing attacks if the defended receiver has one antenna. The attack strategy of concern starts by false GNSS radio-navigation signals exactly top of the true signals. The false signals increase in , lift the receiver tracking loops off of the true , and then drag the tracking loops and the solution to erroneous, but consistent results. paper develops codeless and semi-codeless spoofing methods for use in inexpensive, narrow-band GNSS receivers. Detailed algorithms and are developed that use the encrypted military (Y) code on the L1 GPS frequency in order to defend open-source civilian C/A code. The new detection are similar to methods used in civilian dualfrequency receivers to track the P(Y) code on L2 by -correlating it with P(Y) on L1. Successful detection actual spoofing attacks is demonstrated by off-line of digitally recorded RF data. The codeless can detect attacks using 1.2 sec of correlation, the semi-codeless technique requires correlation of 0.2 sec or less. This technique has been in a narrow-band receiver with a 2.5 MHz RF front-end that attenuates the P(Y) code by 5.5 dB.
No takes yet. Share an insight, caveat, or question.
A 2018 study studied this question.