Orbit accuracy analysis of TianQin gravitational wave detector using BDS-3 inter-satellite links

The TianQin space-borne gravitational wave detector will orbit at an altitude of 1.0×10 5 km with an arm length of 1.7×10 5 km, structured in an equilateral triangular satellite formation. The TianQin project delineates detailed requirements for orbit determination during both the launch phase and subsequent scientific experimentation. This paper pioneers the investigation of Precise Orbit Determination (POD) for TianQin utilizing the third generation of BeiDou global navigation satellite system (BDS-3) Inter-Satellite Link (ISL) through simulation. By analyzing the visibility, the feasibility of using BDS-3 ISLs for TianQin POD is explored. Furthermore, a refined Solar Radiation Pressure (SRP) model is developed, and the POD accuracy of TianQin is assessed, considering factors such as arc length, ranging intervals, and error sources. The results indicate the following: (A) Visibility between TianQin and BDS-3 satellites is intermittent, with an average of 10.6 BDS-3 satellites visible to TianQin, and the average Root Mean Square (RMS)value of Position Dilution of Precision (PDOP) for TianQin is 48.13. (B) POD accuracy improves with shorter ranging intervals. (C) The error in ephemeris is the dominant factor affecting the POD accuracy. (D) The establishment of three links between TianQin and the BDS-3 satellites satisfies the POD requirements of TianQin. With a ranging interval of 600 s and over a 7-day arc, the average three-Dimensional (3D) position accuracy of the three TianQin satellites is 1.35 m, while the 3D velocity accuracy is 0.08 mm/s.