GNSS Performance Research for MEO, GEO, and HEO

Abstract

GNSSs such as GPS, GLONASS, Galileo, and Beidou have demonstrated to be a valid and efficient system for various space applications in LEO. Since the 1990s precise GNSS-based positioning of GEO, MEO, HEO, and even deep space exploration satellites has also been considered feasible. This paper analyzes the GNSS satellite visibility and PDOP performances for 6 space users, including two GEO, one MEO, and three HEO satellites. The simulation results show that a single GNSS receiver with the sensitivity of about −180 to −188 dBW is enough for space user below 50,000 km while the receiver of a Lunar explorer must be able to process the received signal low to −202 ~ −208 dBW. As for a multi-GNSS receiver, the sensitivity requirements decrease about 2–4 dBW compared with the single GNSS one. Viewed from the sensitivity standpoint, a GPS-only receiver and a BDS+GPS receiver are the best single GNSS and multi-GNSS choice for most of the six space users while a Beidou-only receiver performs the best for GEO1 satellite which is fixed above the Asia-Pacific area. It can be concluded that for the space users below 50,000 km, it is possible to attain an average PDOP of below 20 with a receiver sensitivity no higher than −184 dBW. An important conclusion drawn from the analysis is that the higher the space user flies, the more important role multi-GNSS application plays.