Centimeter precise orbit determination for the Swarm satellites via undifferenced kinematic method

• Main Authors: ZHANG Bingbing, NIU Jiqiang, WANG Zhengtao, XU Feng, TIAN Kunjun
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2021-01-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: swarm satellite; precise point positioning; undifferenced kinematic method; batch least squares estimation method; centimeter level
• Online Access: http://xb.sinomaps.com/article/2021/1001-1595/2021-1-27.htm

Using dual-frequency satellite-borne GPS observations from May 24 to May 30, 2015, the linear combination of Melbourne-Wübbena and ionosphere-free linear combination, based on the basis of precise point positioning technology, the batch least squares estimation method is used to precisely determine the Swarm undifferenced kinematic orbits with different orbital attitudes. The orbit accuracy is assessed using three methods, which include satellite-borne GPS phase observation residuals analysis, comparison with ESA reduced-dynamic orbits and external evaluation with SLR measurements. The results indicate: ①Swarm satellite-borne GPS phase observation residual RMS is in the range of 6~7 mm level. ②Comparisons with reduced-dynamic orbits computed by European Space Agency (ESA), radial, along-track and cross-track orbit difference RMS are in the range of 2~4 cm level. ③Comparisons with kinematic orbits computed by ESA, Radial, along-track and cross-track orbit difference RMS are in the range of 1~2 cm level. ④The external validation with satellite laser ranging (SLR) measurement shows RMS errors are in the range of 3~4 cm level. Therefore, it is feasible to use the undifferenced kinematic orbit determination method and the orbit determination strategy provided in this paper to carry out the precise orbit determination of swarm series satellites. The orbit determination accuracy is centimeter level.