GLONASS signal characteristics analysis and navigation performance for geostationary satellites

The utilization of the global navigation satellite system (GNSS) is becoming an attractive approach for autonomous navigation of the geostationary orbit (GEO) satellites. As one of the global navigation systems, the feasibility of using GLONASS in high-orbit spacecraft has attracted attention. A receiver compatible with GLONASS has been mounted in the GEO satellites of TJS-2 and TJS-5 to demonstrate the ability to track signals and real-time orbit determination. In accordance with flight data, the GLONASS signal characteristics are analyzed, including the observation availability and distribution. When the side lobe signals are considered, the mean number of GLONASS satellites tracked increases from 1.8 to 5.8. The transmit power of each GLONASS satellite was estimated by using the C/N ₀ measurements. Based on the influence analysis results, we found that the side lobe signal transmit power plays an important role in increasing the number of observations. In particular, we investigate the characteristics, such as quantity, C/N ₀, and doppler, of the GLONASS antipodal satellite signals tracked simultaneously in the GEO case. We give the navigation performance assessment based on GLONASS-only flight data through comparisons with the precision reference orbits. For single-epoch least square solutions, the root mean squares (RMS) of position differences in radial, along-track, and cross-track is 157.0, 29.5, and 21.5 m, respectively. The navigation accuracy is significantly improved when using the real-time orbit determination method, and the RMS of position differences in radial, along-track, and cross-track is 5.19, 8.98, and 3.15 m, respectively.