Analysis of effect of anti-spoofing signal for mitigating to spoofing in GPS L1 signal

In this paper, we introduce the type of spoofing signal and the method of spoofing mitigation. The spoofing has three type: simplistic, intermediate, sophisticated and we will be interested in the intermediate spoofing. The intermediate spoofers synchronize its counterfeit GNSS signals with the current broadcast GNSS signals. So, if the receiver is attacked by a spoofer, it should be able to detect the spoofing signal through the absolute and relative GNSS signal strength, signal strength changing rate, Bound and compare range rates, etc. There are two way to mitigate spoofing signal, elimination of spoofing channel through the signal processing and counterbalance of spoofing signal through the RF phase control. For simulation, we generated the intermediate spoofing signal using the software GNSS signal generator simulator(SGGS), the intermediate spoofers synchronize its counterfeit GPS signals with the current broadcast GPS signals and generated the anti-spoofing signal to mitigate the spoofing signal. The software GPS receiver simulator(SGRS) received the mixed signal the spoofing, anti-spoofing and normal signal from SGGS, and process the signals. In paper, we can check that the DLL and PLL tracking loop error are generated and pseudo-range is changed linear according to mitigate to spoofing signal when the anti-spoofing signal is entered. As a result, we can check that navigation solution is changed from abnormal by spoofing signal to normal by anti-spoofing signal.