Galileo Constellation MEO Only -- Advantages and Disadvantages

Jacek Januszewski

Abstract:	Nowadays there are two world wide satellite navigation systems ¨C American GPS and Russian GLONASS. A new system ¨C Galileo will be constructed by Europe. The most probable numbers of visible satellites above a certain limit ¨C masking elevation angle Hmin for Galileo system at different latitude of the observer and relevant distributions of GDOP (Geometric Dilution Of Precision) coefficient values (in per cent, over 8 intervals) were calculated and presented in this paper. The calculations were realized for two the most possible Galileo constellations (MEO only) ¨C 27 or 30 satellites, distributed in three planes. Elevation Hmin was assumed 0O, 5O, 10O and 15O. The latitude of observer 0O¨C90O was divided into 9 zones, each 10O wide. As the number of satellites used for pseudorange measurements can be less than the number of satellites visible at a given moment and certain point on the Earth (for many reasons) additional calculations were realized for assumption of 1, 2 or 3 non operational satellites. All calculations, based upon a reference ellipsoid WGS- 84, were made with the use of author's simulating program. The geographic-time coordinates of the observer were generated by random-number generator with uniform distribution. As the possibility of fix position depends on the relative position of the satellites on the orbits the calculations were made for different combinations. As the results we can say ¨C the position of observer in mode ¡°3D¡± could be obtained for Hmin¡Ü15O in each zone of latitude for 0, 1 or 2 non operational satellites for both constellations.
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:	2125 - 2133
Cite this article:	Januszewski, Jacek, "Galileo Constellation MEO Only -- Advantages and Disadvantages," 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. 2125-2133.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In