High Accuracy Navigation for Geostationary Satellite TTS-II via Space-borne GPS

摘要

This study investigates a GPS based navigation performance for Geostationary (GEO) satellite Telecommunication Test Satellite II (TTS- II) by analyzing the In Orbit Test (IOT) data. Depending on the improved receiver for long-distance and weak signals, TTS- II can receive signals on L1 frequency from 6-8 GPS satellites on the far side of the earth, with which the Position Dilution of Precision (PDOP) can decay above 10, and the accuracy of traditional single point positioning (SPP) using code data can only reach 40m or even worse. In order to achieve high accuracy navigation, we employ a reduce-dynamic and kinematic combined near real-time Orbit Determination (OD) processing strategies by taking both the code and phase data into account. However, the signal interruption caused by the blocking of the earth and the weak signal strength will increase the amount of ambiguity parameters. Plus the uncorrected ionospheric effects, the Root Mean Square (RMS) value of 1-day post-fit phase residuals is about 9.58cm. Based on a set of 7-day data in the Mid-April 2018, the OD result shows a RMS value of overlap orbital difference as 1.03m, 1.82m, and 0.34m at radial, along-track, and cross-track direction respectively, which indicates a significant improvement in the aspect of navigation accuracy in contrast with the traditional ground-based technologies for GEO satellites.