An Investigation of Precise Orbit and Clock Products for BDS-3 from Different Analysis Centers

Abstract

A quality evaluation of precise products for BDS-3 constellations is presented for the first time in this contribution. Then, the tropospheric delay retrieval and positioning performance of BDS-3 precise point positioning (PPP) solutions using the precise products (gbm, wum, iac, sha, cnt) with observations from 24 stations from DOY 280 to 317 in 2020 was comprehensively investigated. The orbit comparisons present consistencies of 0.09–0.22 m for the C19–C37 satellites and of 0.5–1.2 m for the C38–C46 satellites among the final products. The standard deviation (STD) values of the clock differences of iac showed the best agreement with those of gbm, followed by wum, sha. The clock differences performance of cnt was the worst. For BDS-3 PPP solutions with five Analysis centers (ACs) products, the median convergence times of static PPP mode incorporating the gbm, wum, iac, sha, and cnt products were 31.0, 33.5, 34.5, 37.8, and 72.0 min, respectively; the median convergence times of kinematic PPP model incorporating the same products were 40.5, 41.0, 50.5, 55.0, and 94.0 min, respectively. The positioning accuracies in the static and kinematic modes were approximately 1–4 cm, 2–6 cm in the horizontal and vertical components, respectively. With the final products in kinematic mode, the performance of PPP with real-time products (cnt) is poorer than all PPP with final products. The median of ZTD accuracies of the five products gbm, wum, iac, sha, and cnt were 7.84, 7.58, 7.04, 7.19, and 10.1 mm, respectively, and the accuracy differences were very small among five AC products (gbm, wum, iac, sha).

Comparison and Assessment on Long-Term Performance of BDS-2/BDS-3 Satellite Atomic Clocks

“…Since January 2019, WHU has provided BDS-2 and BDS-3 precise clock offset products (ftp://igs.ensg.ign.fr/pub/ igs/products/mgex/). Moreover, the STD of WHU BDS-2 and BDS-3 precise clock offset products is 0.51 ns [31] and 0.34 ns [32], respectively, which meets the requirements of analyzing the characteristics of BDS satellite atomic clocks. Thus, WHU precision clock products with a sampling interval of 30 s from 1 January 2019 to 3 July 2020 are selected in this paper to analyze the performance and the characteristics of BDS satellite atomic clocks.…”

BDS-2/BDS-3 combined precise time-frequency transfer with different inter-system bias estimation strategies and different analysis centres products

“…If ISB with high temporal stability, ISB can be calculated as constants by equation ( 9). If ISB variations with time and is strongly related to the preceding and the following epochs, ISB can be calculated as a random walk by equation (10). If the ISB is independent of the preceding and the subsequent periods, then ISB can be calculated as a random walk by equation (11).…”

“…Cao et al [9] demonstrated that the positioning performance of the BDS-2/BDS-3 was improved by more than 50% compared with BDS-2. Shen et al [10] analyzed the quality of BDS-3 precision products and evaluated the BDS-3 positioning performance of 24 stations by using five analysis centers (ACs) products. Ge et al [11] proved that BDS-3 and GPS real-time (RT) PPP have the same accuracy.…”

Sub-meter-level navigation with an enhanced multi-GNSS single-point positioning algorithm using iGMAS ultra-rapid products

“…Nowadays, ultra-rapid products are estimated by both IGS and International GNSS Monitoring and Assessment System (iGMAS) independently. IGS uses eight ACs: Centre for Orbit Determination in Europe (CODE), Center National d'Etudes Spatiales and Collecte Localisation Satellites (CNES/ CLS), Wuhan University (WHU), Deutsches GeoForschungs Zentrum (GFZ), Japan Aerospace Exploration Agency (JAXA), Technische Universität München (TUM), Shanghai Astronomical Observatory (SHAO), and Information and Analysis Centre (IAC) (Shen et al., 2021). In addition to the IGS products, the Chinese project called iGMAS provides products obtained from combinations of its own ACs.…”