Impact of ISB stochastic models on LEO satellite clock estimation with onboard multi-GNSS observations

作者：Wei Xie, Kan Wang, Jinqian Wang, Beixi Chen, Meifang Wu, A. el-Mowafy, Xuhai Yang · 发表于：Measurement science and technology · 年份：2025 · DOI：10.1088/1361-6501/adc7a7 · 被引用次数：5 · 研究领域：Physics

High precision of real-time (RT) low Earth orbit (LEO) satellite clocks is crucial for enabling future LEO-enhanced positioning, navigation, and timing services. For filter-based RT processing, multi-GNSS observations from onboard LEO satellites can strengthen the observation model and improve the LEO precise orbit determination, but have limited improvement effect on the clock estimation. The time references for RT GNSS clocks of different constellations (even from the same analysis center) are different and vary with time. This requires estimating constellation-wise LEO satellite clocks or time-varying inter-system biases (ISBs). This contribution investigates multi-GNSS LEO satellite clock and the corresponding signal-in-space ranging errors (SISRE) using GPS/Galileo observations collected onboard Sentinel-6A satellite, and GNSS products from various analysis centers with different latencies, including the Centre National d’Etudes Spatiales real-time (RT), the GeoForschungsZentrum Multi-GNSS Experimental (MGEX) rapid, the European Space Agency MGEX final, and the Wuhan University MGEX final products. Three ISB stochastic models were implemented, i.e. the constant, the random walk, and the white noise models. Results show that the ISB estimates exhibit systematic effects of orbital periods (ca. 1.85 h) when applying the random walk or white noise models using the post-processing products. The white noise model shows the best performance when applying the RT GNSS products wi...