Simulation and accuracy analysis of orbit determination for TianQin using SLR data

Abstract

TianQin project is a space gravitational wave detection project initiated by Sun Yat-sen University. It has high requirements for detectors’ orbit accuracy in the stages of orbit entry and scientific experiment operation. We obtain the different combinations of radial position errors and along-track velocity errors after analyzing the detectors orbit errors according to the stability requirements of TianQin constellation. Satellite laser ranging (SLR) is the space geodetic technique with the highest accuracy of range measurement, which is a commonly used method for satellite orbit determination. This paper uses solely simulated SLR data to determinate the precise orbit of TianQin detectors. We examine how the number of stations, the distribution of stations, and the measurement errors affect the SLR-only orbit determination accuracy. The results demonstrate that: (a) for the 7 days solution with 1 cm random errors and 0.5 cm systematic errors of SLR simulations, the average orbit determination accuracy of TianQin detectors is increasing from 27.37 m when using 5 Chinese stations to 9.34 m when using 6 Chinese stations. (b) The orbit determination accuracy can be significantly improved by optimizing the distribution of stations, which is increasing from 9.34 m for regional distribution to 1.75 m for global distribution when the number of stations is six. (c) When employing 6 Chinese stations, each 1 cm of random errors results in a deterioration in position accuracy by 19% and in velocity accuracy by 23%, each 1 cm of systematic errors affects 14% for position accuracy and 15% for velocity accuracy, respectively. While the impact of measurement errors on the orbit determination accuracy is aggravated when using 6 global distribution stations, which are 35% and 33% of 1 cm random errors and 17% and 20% of 1 cm systematic errors, respectively.