Network-Assistance to Improve Joint 5G and GNSS Positioning for GNSS Anti-Spoofing

Abstract

Spoofing is a false transmission of global navigation satellite system (GNSS) signals, and it aims to mislead a GNSS receiver. Although the unauthorized transmission of signals in the GNSS frequency range, and thus spoofing, is prohibited, there are a significant number of attacks worldwide. Without any spoofing detection method the GNSS receiver is helpless against an attack but the detection requires additional receiver complexity, which not all receiver have readily available. Coupling of different sensors, GNSS with integrated navigation system (INS) or 5th generation mobile networks (5G), enhances the robustness. But altering the spoofed signal within the tolerances of the other sensors limits the sensor fusion detection. Having pre-information from one of the fused systems if there is a spoofing attack ongoing, can improve the overall performance and enhance the system reliability. With the new 5G standard, such information can be shared. This paper presents a use case where early spoofing reporting from the network can assist the fusion algorithms adapt and obtain superior performance promptly. Three test cases: unspoofed, spoofed, and spoofed with network assisted alert flag, are explored. Therefore, a measurement campaign was conducted to record the 5G data. The GNSS data is simulated for a fair comparison, as a spoofing attack can only be simulated. For each test case the standalone GNSS and 5G, and the 5G-GNSS fused approach is processed. These are compared to analyse the position performance and to showcase the advantage of the network assistance.