Galileo Commercial Service from the Early Definition to the Early Proof-of-Concept

J. David Calle, Enrique Carbonell, Irma Rodríguez, Guillermo Tobías, Eckart Göhler, Oscar Pozzobon, Matteo Cannale, Ignacio Fernández

Abstract:	Since 2012 the European Commission has been working on the definition studies and the demonstration of the capabilities of one of the four services of Galileo, the Commercial Service (CS). The CS was introduced in the Galileo mission with the aim to create added value with respect to the Galileo Open Service and other GNSS signals freely available, and also to create potential revenue to support the maintenance of the Galileo services in the future. Two services were deeply analysed during the Galileo CS Definition phase: Authentication and High Accuracy. High Accuracy is understood as the ability of the system to provide a positioning accuracy of a few centimeters, and Authentication is defined as the ability of the Galileo signals to ensure the user that they are transmitted from the Galileo satellites and not from any other source. Both services foresee to use of the available bandwidth in the Galileo E6 signal to disseminate the CS data to the users. In the frame of the Galileo CS definition studies, one of them led by GMV, an extensive experimentation campaign was carried out in order to evaluate the potential performance of the Galileo Commercial Service with different system architectures regarding, for example, uplink/downlink capabilities and E6 bandwidth allocation between services. In the specific case of the High Accuracy service, the results demonstrated that the number and location of the uplink antennas and the signal-in-space interface design – available bandwidth to transmit corrections to the navigation messages and corrections update rates - do have an impact on the achievable performance in terms of convergence time, positioning error and availability. These different key performance parameters were assessed under different user scenarios: static and dynamic users, open-sky and urban environment conditions. Furthermore, the sensitivity with respect to certain parameters such as the masking angle was also evaluated. The results and conclusions of the experimentation campaign aimed at evaluating the potential performance of the Galileo High-Accuracy service were based on the high-accuracy products provided by GMV’s magicPPP solution and the simulations performed with the GMV’s Stargate tool, which is able to simulate the uplink/downlink capabilities of a GNSS system and provide the associated availability performance at user level. The best positioning performances were achieved in an open sky environment with a static receiver obtaining a positioning error (horizontal, RMS) below 7 cm. Under the same environment conditions, the performances obtained for a kinematic receiver compared with the RTK algorithm showed an RMS below 10 cm in horizontal and about 20 cm in vertical. Regarding the dissemination strategy, the main conclusions drawn from the results of the Stargate simulations were that the CS availability in Galileo FOC (assuming 27 satellites), is about the 73% with 10 uplink antennas, but it could be improved with an additional uplink station or an additional antenna per site up to the 95% or better. At the beginning of 2014, the development of the CS Demonstrator was launched with the objective of developing an end-to-end system to test the real capabilities of the service. The demonstrator will be able to generate CS data suitable to be broadcast through the E6 signal, develop a CS Receiver capable to receive and process those signals, authenticate the navigation message by means of several authentication solutions and calculate an improved PVT solution using High Accuracy ephemeris corrections. The system will be fully developed by the beginning of 2015 and the integration with Galileo Service Centre will be ready by late 2015. Fortunately, we do not have to wait till 2015 to show the first results and demonstrate the capabilities of the CS thanks to a preliminary demonstrator, the CS Early Proof of Concept (EPOC), which was developed during the first half of 2014 and started the SIS tests on July 2014. The EPOC can be described as a testbed version of the CS Demonstrator with limited functionalities. Concretely, the EPOC is able to generate and provide off-line data that will be later transmitted through E6 signals during certain weekly slots to test the reception of the E6-B/C signals, and analyse the achievable performances of future potential services. The EPOC is composed by several components: a module able to generate CS data suitable to be broadcast by the Galileo satellites in the E6 signal, a CS Receiver able to receive and record the information the E6 signal, an authentication client able to authenticate data received in the E6, a PVT algorithm which uses the authenticated High Accuracy information and finally a module able to compare and analyse the generated E6 files with the recorded by the CS receiver. The EPOC SIS-Tests will be focused on demonstrating and testing the envisaged characteristics for the final service at its earliest stage. The tests are performed on a weekly basis. The procedure starts arranging the time slot for the test with ESA, in charge of the Galileo Core Infrastructure; the E6 data for that period is generated and provided to the GMS operators for its broadcasting. The CS Receiver is set up at the agreed time to record the E6, and finally that information is processed by the authentication client, the PVT algorithm and analysed versus the generated information. These tests are performed under different environment conditions (static open-sky, kinematic open-sky, static urban environment and kinematic urban environment), and with and without E6 spreading code encryption. The objective of this paper is twofold, firstly to present the context of the Galileo CS and the different activities and results obtained during the Galileo CS Definition phase, and secondly to introduce the CS Early Proof-Of-Concept and show the first results obtained using the real Galileo E6 signals during the EPOC-SIS-Tests.
Published in:	Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014) September 8 - 12, 2014 Tampa Convention Center Tampa, Florida
Pages:	392 - 405
Cite this article:	Calle, J. David, Carbonell, Enrique, Rodríguez, Irma, Tobías, Guillermo, Göhler, Eckart, Pozzobon, Oscar, Cannale, Matteo, Fernández, Ignacio, "Galileo Commercial Service from the Early Definition to the Early Proof-of-Concept," Proceedings of the 27th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2014), Tampa, Florida, September 2014, pp. 392-405.
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