Evaluating EGNOS augmentation on a military helicopter

Alain Muls and Frank Boon

Abstract:	The European Geostationary Navigation Overlay System, or EGNOS, is a satellite based augmentation system for GPS and Glonass which shall ensure the accuracy and integrity for multi-modal transport applications. The EGNOS signal is provided through an infrastructure based on space and ground segments, which are currently operational in test mode. EGNOS is the basis on which many future satellite navigation services will be developed. The goal of EGNOS is to augment GPS and Glonass in order to provide: accuracy better than stand-alone, increased availability, guaranteed integrity and continuity of service in order to meet navigation requirements for multi-modal applications. The EGNOS Implementation Phase started in November 1998 and the EGNOS prototype (ESTB) is available since February 2000. The operational area of EGNOS is the European continent and its prime mission is to service the civil aviation community. To evaluate the current performance of EGNOS enhanced navigation with respect to traditional GPS aiding methods such as DGPS a test flight was performed. This test flight reflected the daily operations carried out with a military helicopter. In addition to this liaison flight path a tactical flight was performed over the southern part of Belgium. Special manoeuvres were also introduced stressing the system and decreasing satellite visibility due to masking effects. A Septentrio PolaRx-1 GPS/EGNOS/WAAS receiver operating on board allows data processing in 3 different navigation modes: GPS stand alone, differential GPS and SBAS augmented GPS. An OTF reference trajectory using a nearby static reference receiver provides assessment the quality of each navigation solution. Contrary to the expectations from high dynamics and poor satellite visibility, the results show a high availability (98.3% tracking) of the EGNOS signal. The SBAS augmented GPS solution demonstrates better accuracies than the GPS stand alone solution, similar to the DGPS track.
Published in:	Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001) September 11 - 14, 2001 Salt Palace Convention Center Salt Lake City, UT
Pages:	2458 - 2462
Cite this article:	Muls, Alain, Boon, Frank, "Evaluating EGNOS augmentation on a military helicopter," Proceedings of the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2001), Salt Lake City, UT, September 2001, pp. 2458-2462.
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