What is Achievable with Current COMPASS Constellations?

Maorong Ge, Hongping Zhang, Xiaolin Jia, Shuli Song, Jens Wickert

Abstract: The development of the Chinese Satellite Navigation System COMPASS is scheduled into three phases: experimental system, regional system and global system. The regional system will be completed around the end of 2012 with a constellation of five Geostationary Earth Orbit (GEO) satellites and five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. By 2020 it will be extended into a global system. Now it is due to the end of the regional system development, one of the most interesting questions may be what can be achieved with the current COMPASS constellation besides the standard positioning service. In this study, one month data from a tracking network with nine stations in China and its surroundings is employed to demonstrate the capacity of the COMPASS with a constellation comprising of three GEOs and four IGSOs in operation. First of all, the data is processed for precise orbit and clock determination which is essential for any GNSS system. Then, Precise Point Positioning (PPP) in both static and kinematic mode is carried out for a user station by utilizing the estimated orbits and clocks. The derived positions and zenith tropospheric delays are compared with that from GPS data. Furthermore, predicted orbits are generated for estimating satellite clocks epoch-wisely. Estimated clocks and the predicted orbits are provided to a user station to simulate real-time PPP service. The result is assessed by the position differences between the estimates and that of the daily GPS solutions. The results show that the 3D-RMS of the overlapped orbits for GEOs and IGSOs are 330 cm and 51 cm, respectively and the clock RMS is about 0.3 ns. The accuracy of the static PPP with data longer than 6 hours is about 1 cm in horizontal and 2 cm in vertical but with a bias of 4 cm, while the kinematic PPP can reach cm-level accuracy. The PPP derived ZTD compared with that from GPS has an agreement of 15 mm. The simulated real-time PPP demonstrates an accuracy of 1 to 2 dm.
Published in: Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012)
September 17 - 21, 2012
Nashville Convention Center, Nashville, Tennessee
Nashville, TN
Pages: 331 - 339
Cite this article: Ge, Maorong, Zhang, Hongping, Jia, Xiaolin, Song, Shuli, Wickert, Jens, "What is Achievable with Current COMPASS Constellations?," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 331-339.
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