Abstract:

The analysis of the onboard high-orbit GNSS navigation receiver system applied on the LuTan-04A (LT4A)， the world′s first Inclined Geosynchronous Orbit (IGSO) Synthetic Aperture Radar (SAR) satellite， is presented. The study investigates the precise orbit determination (POD) performance of the high-orbit GNSS receiver system and reports its engineering application for post-precise orbit determination for the first time. By collecting on-orbit data of BDS and GPS signal anomalies， the quality of onboard observational data and the POD are analyzed and evaluated. Experimental results indicate that the LT4A satellite onboard high-orbit GNSS navigation receiver system can stably capture and track BDS B1I and GPS L1 navigation signals， meeting the requirements for high-orbit real-time positioning， orbit determination， and post-mission precise orbit determination. Utilizing joint orbit determination of onboard BDS+GPS， the in-track accuracy can achieve radial better than 1.87m and three-dimensional better than 3.07m. In response to the characteristics of high-orbit navigation satellite acquisition and the timeliness requirements of applications， the orbit determination system can operate fully automatically throughout the entire process， ensuring the smoothness and continuity of the orbit， and controlling the introduction of high-order Legendre errors. The relevant achievements of this study can be applied to future high-orbit Earth observation satellite missions equipped with GNSS receivers.

Key words: LuTan-04A, inclined geosynchronous orbit, synthetic aperture radar, global navigation satellite system, precise orbit determination, onboard real-time autonomous orbit determination ,