Experimental Study on the Precise Orbit Determination of the BeiDou Navigation Satellite System

Abstract

The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better.

Precise Point Positioning Using the Regional BeiDou Navigation Satellite Constellation

“…The PANDA (Positioning And Navigation Data Analyst) software is used for the data processing. The software was developed at the GNSS Research Center in Wuhan University (Liu and Ge, 2003;Shi et al, 2008) and has recently been adapted for BDS data processing (Shi et al, 2012;Zhao et al, 2013;He et al, 2013). Similar to other scientific GNSS software packages, it includes the following basic modules: data pre-processing, orbit integration, parameter estimation, data editing and ambiguity-fixing.…”

“…Satellite attitude control mode has also not been announced. Moreover, the attitude control mode of the BDS satellites is assumed to be the same as that of the GPS Block IIR satellites (He et al, 2013).…”

“…Besides the above-mentioned positioning services, precise relative positioning has already been investigated Montenbruck et al, 2012) and precise orbit determination and clock estimation has also been demonstrated Ge et al, 2012b;Shi et al, 2012;Steigenberger et al, 2012;Zhao et al, 2013;He et al, 2013). Precise Point Positioning (Zumberge et al, 1997) based on the products has also been undertaken in post-processing and simulated in real-time mode for validating the estimated orbit and clock products (Kouba and Heroux, 2001).…”

“…All stations are equipped with UR240 dual-frequency GPS/BeiDou receivers and UA240 antennas manufactured by the UNICORE Company in Beijing, China (http://www.unicor ecomm.com/english/). A number of studies have been carried out based on data from this network (Ge et al, 2012a;Shi et al, 2012;Zhao et al, 2013;He et al, 2013).…”

“…Precise orbits and clocks estimated from a global tracking network using the strategy by He et al (2013) are employed in BDS PPP processing in static, kinematic and simulated real-time kinematic mode. The static results using various session lengths and kinematic trajectories are compared with the daily GPS PPP results using IGS precise orbits and clocks in order to assess the performance of BDS PPP in terms of accuracy and convergence time.…”