Real-time LEO satellite clock estimation with predicted LEO satellite orbits constrained

作者：Wei Xie, Hang Su, Kan Wang, Jiawei Liu, Meifang Wu, Min Zou, Ahmed El‐Mowafy, Xuhai Yang · 发表于：GPS Solutions · 年份：2024 · DOI：10.1007/s10291-024-01723-6 · 被引用次数：18 · 研究领域：GNSS positioning and interference、Advanced Frequency and Time Standards、Ionosphere and magnetosphere dynamics

Low Earth Orbit (LEO) satellites can augment the traditional GNSS-based positioning, navigation and timing services, which require real-time high-precision LEO satellite clock products. As the complicated systematic effects contained in the LEO satellite clock estimates limit their high-precision mid- to long-term prediction, high-frequency LEO satellite clocks need to be estimated within a Kalman filter, resulting in a short prediction time for real-time applications. Compared to the clock estimation using Batch Least-Squares (BLS) adjustment, filter-based clock estimation experiences a lower precision. Increasing the model strength by introducing external orbital information, thus, de-correlating the orbital and clock parameters, will benefit real-time clock precision. In this contribution, reduced-dynamic LEO satellite orbits are first estimated using BLS adjustment in near real-time and predicted in the short term. The predicted orbits are then constrained during the Kalman-filter-based clock estimation process. The variance–covariance matrix of the introduced orbital errors is tested for different sets of values in the radial, along-track and cross-track directions when constraining orbits of different prediction times. One week of GPS data from the Sentinel-3B satellite in 2018 was used for validation of the proposed method. When weakly constraining high-accuracy predicted orbits within a prediction time of 20 min, i.e., with a standard deviation of the constraint set t...