Server-Based Galileo PRS Snapshot Positioning for Remotely Piloted Aircraft Systems

The encryption used in Galileo public regulated service (PRS) ensures authentic, reliable time and position data, enabling the deployment of security-critical applications that unprotected global navigation satellite system (GNSS) receivers cannot support. However, conventional Galileo PRS receivers with integrated security module (SM) are not suitable for all applications, even when a secure solution is required: They are more expensive than standard Open Service (OS) receivers and require specific handling due to the key management. In addition, size, weight, and power (SWaP) constraints are challenging for a wide range of miniaturized applications. This paper discusses the methods, setups, and first real-world demonstration of server-based PRS processing in a Remotely Piloted Aircraft Systems (RPAS) scenario under spoofing. In this approach, PRS signal processing is outsourced to a secure server that hosts the required SM. In this architecture, the receiver, referred to as the snapshot receiver or user terminal (UT), captures short segments of raw intermediate frequency (IF) signal data, known as snapshots. The system supports two operational modes-spreading code transmission (SCT) and sample and process (SAP)-each tailored to different application requirements. This system architecture was evaluated in a real-world demonstration within a protected test area using jamming and spoofing experiments. The results demonstrate the robustness of a server-based position, velocity, and time (PVT) against spoofing threats while achieving low latency, showcasing its potential for secure and reliable navigation in real-world scenarios.