New-Generation BeiDou (BDS-3) Experimental Satellite Precise Orbit Determination with an Improved Cycle-Slip Detection and Repair Algorithm

Abstract

Currently, five new-generation BeiDou (BDS-3) experimental satellites are working in orbit and broadcast B1I, B3I, and other new signals. Precise satellite orbit determination of the BDS-3 is essential for the future global services of the BeiDou system. However, BDS-3 experimental satellites are mainly tracked by the international GNSS Monitoring and Assessment Service (iGMAS) network. Under the current constraints of the limited data sources and poor data quality of iGMAS, this study proposes an improved cycle-slip detection and repair algorithm, which is based on a polynomial prediction of ionospheric delays. The improved algorithm takes the correlation of ionospheric delays into consideration to accurately estimate and repair cycle slips in the iGMAS data. Moreover, two methods of BDS-3 experimental satellite orbit determination, namely, normal equation stacking (NES) and step-by-step (SS), are designed to strengthen orbit estimations and to make full use of the BeiDou observations in different tracking networks. In addition, a method to improve computational efficiency based on a matrix eigenvalue decomposition algorithm is derived in the NES. Then, one-year of BDS-3 experimental satellite precise orbit determinations were conducted based on iGMAS and Multi-GNSS Experiment (MGEX) networks. Furthermore, the orbit accuracies were analyzed from the discrepancy of overlapping arcs and satellite laser range (SLR) residuals. The results showed that the average three-dimensional root-mean-square error (3D RMS) of one-day overlapping arcs for BDS-3 experimental satellites (C31, C32, C33, and C34) acquired by NES and SS are 31.0, 36.0, 40.3, and 50.1 cm, and 34.6, 39.4, 43.4, and 55.5 cm, respectively; the RMS of SLR residuals are 55.1, 49.6, 61.5, and 70.9 cm and 60.5, 53.6, 65.8, and 73.9 cm, respectively. Finally, one month of observations were used in four schemes of BDS-3 experimental satellite orbit determination to further investigate the reliability and advantages of the improved methods. It was suggested that the scheme with improved cycle-slip detection and repair algorithm based on NES was optimal, which improved the accuracy of BDS-3 experimental satellite orbits by 34.07%, 41.05%, 72.29%, and 74.33%, respectively, compared with the widely-used strategy. Therefore, improved methods for the BDS-3 experimental satellites proposed in this study are very beneficial for the determination of new-generation BeiDou satellite precise orbits.

A BDS-2/BDS-3 Integrated Method for Ultra-Rapid Orbit Determination with the Aid of Precise Satellite Clock Offsets

“…In orbit determination, un-differenced ionosphere-free code and a phase combination of B1I and B3I observations were conducted. Moreover, the arc length is set to three-days, and a parameter configuration similar to [10,13] is used. It is noted that the un-differenced and double-differenced methods are two popular data processing strategies for orbit determination, and they each have their own advantages and disadvantages.…”

“…In the experiment, the constraint of the clock offset parameter is taken as a condition equation to estimate the orbit determination parameter. In this study, the clock accuracies of the precise clock and broadcast clock are set as 10 m and 5000 m, respectively, which are referenced in [8,13]. Similarly, experiments using 31 days (DOY 30-60, 2019) of data are conducted for the analyses of the orbit results estimated from the use of the constraints on the clock parameters.…”

“…For BDS, research over BDS-2's orbit and clock offset has been mainly focused on the following three key aspects: (1) based on the available regional tracking network [6,7], the data processing strategies are constrained to a small number, and uneven geographical distribution, of ground tracking stations; (2) satellite geometric and physical models are refined [8][9][10], such as attitude models, sun radiation pressure, and the phase centre; (3) multi-GNSS observations are combined to augment BDS-2's performance. BDS-2's orbit determination has been studied extensively to improve accuracy and the relevant algorithms [11][12][13]. Results showed that the three-dimensional root-mean-square error (3D RMS) of the BDS-2's one-day overlapping arc for MEO (and IGSO) and GEO were improved from 0.5 m and 3.0 m to 0.2 m and 1.0 m, respectively.…”

Distributed Orbit Determination for Global Navigation Satellite System with Inter-Satellite Link

“…The distributed autonomous ephemeris updating were discussed for navigation satellites [22]. There are also many researches on developing higher precision orbit determination methods for new BeiDou (BDS-3) experimental satellites in the literature [23][24][25][26]. Currently, the developments for autonomous orbit determination, time synchronization, and autonomous operation and management are wildly investigated.…”

BDS-3 differential code bias estimation with undifferenced uncombined model based on triple-frequency observation

“…As a great advantage of the new generation BDS, the contribution of the ISL in terms of POD was analyzed and confirmed by Ren et al (2017) with different data processing strategies. Taking the limited measurements of BDS-3 into consideration, Hu et al (2018) refined the cycle slip detection and repair strategy in their study to improve the usability of the observations as well as the precision of POD. Besides the frequency compatibility of the new signals, a better performance in terms of measurement noise and anti-multi-path property is also expected.…”