Secure position and time information by server side PRS snapshot processing

An alternative way to benefit from spoofing-resistant Galileo Public Regulated Service (PRS) signals is to use a server side processing concept, where all security-related processing steps are outsourced. Having outlined the architecture with user terminal, communication channel and remote server, the snapshot positioning algorithms with different pseudorange reconstruction methods are presented. To reduce the snapshot size, data compression methods are possible, however, degrading the effective C/N0. The results are demonstrated, processing E1 Pseudo-PRS signals from an RF constellation simulator and applying different compression techniques. Multiple raw data snapshots, with sizes from 810 to 10 kByte are evaluated providing Galileo E1 PRS snapshot positioning 1-sigma accuracy from 1.1 to 6.0 m. Finally, a method to estimate the accuracy from a single snapshot result is outlined.