A Galileo E6-B/C Receiver: Signals, Prototype, Tests and Performance

Abstract

Galileo satellites are transmitting the E6-B/C signals reserved for the Galileo Commercial Service (CS), which aims at providing precise point positioning (PPP) and authentication services, mainly for professional users, through a 492-bps signal and encrypted spreading codes. IfEN GmbH developed and tested a full CS E6-B/C receiver whose results are presented in this paper. This paper mainly covers four aspects: the Galileo E6-B/C signals, the Galileo CS receiver prototype, the testing campaign and the test results. The first part of the paper focuses on the CS signal definition. While most elements of the CS signal are in the public domain, there is no single reference that provides a full description of all the information required to process the E6-B/C (un-encrypted) signals in a receiver. This paper presents a comprehensive description of the E6-B/C signal frequencies, power, modulation, primary and secondary codes, data coding scheme and message structure. It must be noticed that the full data structure will partly depend on the future high accuracy service providers and its access may be controlled. While the Galileo Commercial Services will foreseeably be access-controlled, the signals will be partly openly accessible, so that receivers can freely use the 3 frequencies of Galileo (E1, E5 and E6). The second part of the paper describes the Galileo E6-B/C receiver prototype, based on IFEN's NTR receiver. The receiver incorporates E1, E5ab and E6 front-ends and is able to process GPS, Galileo, GLONASS, BDS, SBAS and IRNSS signals. Some receiver specificities related to the E6-B/C signals are also described, as the handling of encrypted codes, the record and storage of sample streams for remote authentication based on encrypted spreading codes, or on-the-fly CS encryption key handling. The third part of the paper presents the test campaign carried out by IFEN GmbH. This part presents an overview of the test scenarios, which included both simulated and real data testing, in static and dynamic (urban, suburban) scenarios. The fourth part of the paper addresses the test results obtained with the CS receiver prototype. The paper finalizes by presenting some conclusions and proposing further work.