Detection and Identification of Inauthentic Signals Based on the Frequency Drift of the GNSS Receiver Clock

The GNSS receiver clock drift can be estimated as part of the Time Differenced Carrier Phase solution. If the solution is computed with simulated carrier phase measurements, the estimated clock drift will also include a component that reflects the drift of the simulator clock. Therefore, even after the simulated signals completely takes over a GNSS receiver, it is still possible to detect the existence of the simulator clock. The detectability depends on the quality of receiver clock and the simulator clock. In this work, a software defined radio GNSS receiver PyChips will be used to track authentic and simulated channels simultaneously. The carrier phase measurements are used to compute the true receiver clock drift, and the quantify the impact of the simulator clocks. Multiple OCXO and atomic clock models are considered and tested.