Precise Real-time Navigation of the Small TJU-1 Satellite Using GPS, GLONASS and BDS

Precise real-time navigation of the small Tianjin University-1 (TJU-1) satellite based on GPS, GLONASS, BDS-2 and BDS-3 is studied in this contribution for the first time. Experimental results showed that (1) the real-time position accuracies could reach the level of 0.6 -0.8 m, 0.9 -1.1 m, 2.0 -3.5 m and 0.18 -0.22 m, respectively, for the solutions based on single GPS, GLONASS, BDS-2 and BDS-3; (2) The multi-GNSS fusion could significantly improve the accuracy, reliability and availability of real-time navigation compared with the single-GNSS solution especially when the observation conditions of a single-GNSS are poor or over some anomalous orbit arcs where only few or even no observations are available; (3) a remarkable real-time orbit accuracy of 0.187 m for 3D position is achieved based on BDS-2 + BDS-3 fusion. These accuracy performances have fully demonstrated that, precise real-time navigation based on multi-GNSS measurements would be a very attractive technique for broad small LEO satellite applications requiring the high-precision real-time orbits.