Patent ID: 7310062
Filing Date: 2007-12-18
Classification: G01S

Abstract:
1. A method of detecting GPS signal tampering using dual antenna diversity while tracking GPS satellites comprising the steps of: measuring a first carrier phase of a first satellite signal at a first antenna with a first GPS receiver; measuring a second carrier phase of the first satellite signal at a second antenna with a second GPS receiver; measuring a first carrier phase of a second satellite signal at the first antenna with the first GPS receiver measuring a second carrier phase of the second satellite signal at the second antenna with the second GPS receiver determining a baseline vector between the first antenna and the second antenna; translating the first carrier phase measurement of the first satellite signal and the first carrier phase measurement of the second satellite signal to a virtual zero baseline condition with the second antenna with the baseline vector; double differencing the translated first carrier phase measurement of the first satellite signal, the translated first carrier phase measurement of the second satellite, the second carrier phase measurement of the first satellite signal, and the second carrier phase measurement of the second satellite signal to obtain double difference residuals; computing a test statistic of the double difference residuals; determining a threshold; comparing the test statistic of the double difference residuals to the threshold; and flagging an inconsistency in measured signals when the threshold is exceeded thereby indicating a tampered signal is present.