Multi-source DOA estimation based on multi-UAV collaboration in complex GNSS spoofing environments

Unmanned Aerial Vehicles (UAVs) are widely used in both military and civilian sectors due to their maneuverability and versatility. However, UAVs rely on the Global Navigation Satellite System (GNSS) for real-time accurate navigation and are therefore vulnerable to attacks, particularly spoofing attacks, in GNSS-challenging environments. Furthermore, UAV payloads are generally limited to carrying only a single antenna, significantly restricting the spatial Degrees of Freedom (DoFs) available. A new scheme is presented to address the challenges posed by multiple spoofing sources for UAV GNSS navigation. Unlike conventional multi-antenna techniques, our approach extends centralised multi-antenna Direction of Arrival (DOA) estimation to distributed scenarios using UAV collaboration techniques. The multi-source DOA estimation of GNSS spoofing is achieved using the space-time DOA matrix (ST-DOAMatrix) technique, which enhances system resilience and spatial DoFs. Simulation results validate the effectiveness of the proposed method and demonstrate the feasibility and potential of the technique in ensuring the proper and safe operation of UAVs using GNSS navigation.