Revealing the Criteria for Detecting the Spoofing and Premediated Interference of GNSS Signals Using the Experimental Simulation Model

The results of the research on the detection of meaconing spoofing or intentional interference of Global Navigation Satellite Systems (GNSS) signals at the initial stage when the user enters the area of the indicated interference are presented. The research was carried out using an experimental simulation model (prototype) of the effects of GNSS/GPS signal spoofing. The prototype included a dual frequency GNSS receiver, two antennas, a combiner and attenuator, a computer for accumulation of measurement information. The impact of spoofing was analyzed using the output measurement information of the receiver. During the experiment, the signals from the first antenna were fed to the input of the receiver through a combiner. After 75 min of observation, the input of the receiver was fed with satellite signals from the second antenna. The amplitudes of the signals from both antennas did not differ much, which can be characterized as the effect of intentional interference or spoofing attack at the initial stage. The receiver output data were recorded, processed and analyzed. The results of the whole experiment have been analyzed. It was found that the main criteria for the presence of interference/spoofing are the signal-to-noise ratio, code and phase pseudorange differences, which change significantly and rapidly. The additional criteria can be the pseudorange standard deviations and a multiple increase of the positioning errors. The data obtained make it possible to indicate the influence of spoofing and to recommend switching to alternative navigational aids.