Implementation and Performance Evaluation of SSC for High-power GNSS Spoofing Attacks

With the increasing attention paid to GNSS security topics, GNSS anti-spoofing technology, including spoofing detection, recognition and mitigation, has developed rapidly in recent years. Among them, spoofing mitigation plays a direct and important role in recovering PVT services in the presence of spoofing attacks. Most current studies focus on low- or medium-power spoofing scenarios where easily deployable measurement-level mitigation works well. However, in existing spoofing practices, due to the difficulty in power control, high-power spoofing attacks also pose an undeniable potential threat to user security through their impact on authentic signal processing, induced by multi-access interference (MAI). Therefore, this work aims to select a typical signal-level mitigation method to be implemented on a practical receiver platform, and then evaluate its anti-spoofing performance under high-power spoofing scenarios. Successive spoofing cancellation (SSC) is selected in this work for its low computational complexity and simple hardware structure. The design details of an anti-spoofing receiver with SSC are introduced from the circuit design of a single spoofing cancellation (SC) block and the control logic in constructing the SSC scheme. Furthermore, a prototype anti-spoofing GPS receiver with SSC is developed based on FPGA/ARM architecture. In wired spoofing experiments, decreases in the carrier-to-noise ratio (CNR) estimates are utilized as a metric for the channel-level resilience against high-power spoofing attacks. Then, the 3-dimentional positioning performance before and after employing spoofing cancelation is investigated. It is found that within a specified tolerance level of CNR degradation, SSC can confer an enhancement of roughly 15dB in one-channel spoofing scenarios. In four-channel spoofing scenarios, such gain will decrease as the power distribution among spoofing signals becomes more uniform. In addition, the results of positioning tests also indicate the MAI mitigation potential of SSC: after employing SSC, the root mean square error (RMSE) of 3D positioning based on the authentic signals improves from 18.34m/7.95m to 3.39m/3.89m in the one-channel/four-channel spoofing experiments when the total spoofing signal power is set 20dB higher than the interested authentic signal.