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's 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 the 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: 1) 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. 2) 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 6. 3) 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.

Analysis and comparison of the orbit determination accuracy of TianQin based on multiple ground-based measurements

“…Meanwhile, 1 cm random errors and 0.5 cm systematic errors are added to each station as its measurement errors. The sampling rate for Nps is set as 300 s in accordance with the product format given by ILRS, the detailed simulation flow can be found in [8]. In POD, the weight ratios between CDSN observations and SLR observations, as well as between S/Ka-band ranging and SLR observations, are set at 1:500 and 1:25, respectively, considering the precision of observational data and sampling rates.…”

“…To ensure operational stability, with constellation arm length changes limited to within 1% and breathing angle variations within ±0.1°, precise positioning of TianQin satellites' radial (R) position and tangential (T) velocity is imperative, requiring accuracies of 5 m and 2 mm s −1 , respectively [8,9]. This underscores the critical need for high-precision orbit determination to guarantee mission success.…”

“…In the context of utilizing SLR data for POD, the current accuracy for Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) satellites is approximately 10 centimeters and 30 centimeters, respectively, with a 7-day arc length [31][32][33][34]. Reference [8] provides an analysis of TianQin satellite POD accuracy based on SLR observations, indicating that the number and distribution of SLR stations are the primary factors influencing TianQin satellites' POD accuracy. With the maturation of satellite POD technology and the increasing demand for orbit accuracy, relying solely on a single tracking method for POD is no longer sufficient to further enhance orbit precision.…”

Determination of Precise Galileo and Sentinel-6A Orbits through the Integration of GNSS and SLR Data

“…And in fact, in the combined GNSS/SLR data processing, the satellites could be regards as space tie for GNSS and SLR, which could become a supplement for the sparse local tie. (Glaser et al, 2019;Klopotek et al, 2020;Thaller et al, 2017;Wang, 2021) Utilizing GNSS and SLR data to determine both Galileo and Sentinel-6A satellites orbits at the observation level shows great potential to improve the orbit qualities (An et al, , 2022Bury et al, 2019). Whereas, as illustrated in Table 1, the number of GNSS observations surpasses the number of SLR observations substantially.…”