GSTAR: an innovative software platform for processing space geodetic data at the observation level

• Published in: Satellite navigation 2023-12, Vol.4 (1), p.18-20, Article 18
• Main Authors: Shi, Chuang, Guo, Shiwei, Fan, Lei, Gu, Shengfeng, Fang, Xinqi, Zhou, Linghao, Zhang, Tao, Li, Zhen, Li, Min, Li, Wenwen, Wang, Cheng, Lou, Yidong
• Format: Article
• Language: English
• Subjects: Algorithms; applications; BDS; BDS/GNSS high-precision products: strategies; C plus plus; Data processing; Design; Efficiency; Engineering; Global positioning systems; GNSS; GPS; Ground stations; GSTAR; Ionosphere; LEO; Linux; Object oriented programming; Orbits; Original Article; Precise clock estimation; Precise orbit determination; Satellites; services; Software packages
• ISSN: 2662-9291; 2662-1363
• DOI: 10.1186/s43020-023-00109-2

To meet the demands for the data combination with multiple space geodetic techniques at the observation level, we developed a new software platform with high extensibility and computation efficiency, named space Geodetic SpatioTemporal data Analysis and Research software (GSTAR). Most of the modules in the GSTAR are coded in C++ with object-oriented programming. The layered modular theory is adopted for the design of the software, and the antenna-based data architecture is proposed for users to construct personalized geodetic application scenarios easily. The initial performance of the GSTAR software is evaluated by processing the Global Navigation Satellite System (GNSS) data collected from 315 globally distributed stations over two and a half years. The accuracy of GNSS-based geodetic products is evaluated by comparing them with those released by International GNSS Service (IGS) Analysis Centers (AC). Taking the products released by European Space Agency (ESA) as reference, the Three-Dimension (3D) Root-Mean-Squares (RMS) of the orbit differences are 2.7/6.7/3.3/7.7/21.0 cm and the STandard Deviations (STD) of the clock differences are 19/48/16/32/25 ps for Global Positioning System (GPS), GLObal NAvigation Satellite System (GLONASS), Galileo navigation satellite system (Galileo), BeiDou Navigation Satellite System (BDS), Medium Earth Orbit (MEO), and BDS Inclined Geo-Synchronous Orbit (IGSO) satellites, respectively. The mean values of the X and Y components of the polar coordinate and the Length of Day (LOD) with respect to the International Earth Rotation and Reference Systems Service (IERS) 14 C04 products are -17.6 microarc-second (µas), 9.2 µas, and 14.0 µs/d. Compared to the IGS daily solution, the RMSs of the site position differences in the north/east/up direction are 1.6/1.5/3.9, 3.8/2.4/7.6, 2.5/2.4/7.9 and 2.7/2.3/7.4 mm for GPS-only, GLONASS-only, Galileo-only, and BDS-only solution, respectively. The RMSs of the differences of the tropospheric Zenith Path Delay (ZPD), the north gradients, and the east gradients are 5.8, 0.9, and 0.9 mm with respect to the IGS products. The X and Y components of the geocenter motion estimated from GPS-only, Galileo-only, and BDS-only observations well agree with IGS products, while the Z component values are much nosier where anomalous harmonics in GNSS draconitic year can be found. The accuracies of the above products calculated by the GSTAR are comparable with those from different IGS ACs. Compared to the