Real-Time Utilization of IGS Stations in SPEED

F. Dufour, P. Larhantec, J.A. Gicquel, S. Boher

Abstract:	SPEED has been developed by ESA in the framework of the European GNSS Evolution Programme (EGEP) to become a central part of the EGNOS test beds in order to test and qualify future EGNOS evolutions. The CNES has significantly contributed to its development and hence, possesses its own SPEED platform since mid-2011. CNES has put in place a SPEED experimentation plan that is on many aspects complementary to the ESA one. SPEED is a powerful tool to simulate, test and even demonstrate an EGNOS-like service. SPEED initially has the very same navigation algorithms and system capabilities than the original EGNOS system, but allow to easily change the navigation kernel and add much more parameterization possibilities (with respect to the algorithms or the system configuration specifically). A SPEED platform has the capability to use EGNOS RIMS data in real time and to disseminate its own navigation message but without the constraints linked to the provision of an operational and certified navigation service. For many months, SPEED has been used extensively by CNES to investigate EGNOS algorithms behaviors or to test EGNOS system configurations variants. Almost all these works have been done using archived data and the fast replay feature of the platform, which is very useful to accelerate the runs (up to at least 7 times). In replay, SPEED already has the capability to use IGS stations measurements as input to the runs (alone or conjointly with EGNOS RIMS data), but a real-time capability was missing. So CNES has decided to develop a new SPEED component to add this important capability to the platform in order to demonstrate a real-time utilization of IGS stations’ measurements into the process of computing valid SBAS navigation messages. This component receives the RTCM fluxes of selected IGS stations in real time and converts them in EGNOS internal format on the fly to feed the SPEED platform that will, in turn, use them to produce a specific navigation service. Using IGS stations can be very interesting to increase the number of measurements over a SBAS service area (in addition to existing GNSS stations), to test an extension of the service in a region not deserved yet, or even to test the replacement of a GNSS station infrastructure by another one. Of course, the navigation algorithms and their parameterization have to be adapted to the specificities of the IGS station measurements. In the paper, we will present two examples of real-time utilization of IGS stations over the European region: the first one in combination with EGNOS RIMS data, and the second one with IGS stations only. The main navigation service performances will be detailed and commented in both cases.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	1890 - 1896
Cite this article:	Dufour, F., Larhantec, P., Gicquel, J.A., Boher, S., "Real-Time Utilization of IGS Stations in SPEED," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 1890-1896.
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