Abstract:

The long latency of international GNSS service (IGS) final ephemerides and the influence of the first order differential ionospheric path delay are two problems of precise and rapid inter-satellite differential relative positioning for long baseline satellite formation using dual-frequency global positioning system (GPS). To deal with these problems, a dynamic single difference ionosphere free combination relative positioning method based on IGS ultra-rapid ephemerides is proposed. In this method, IGS ultra-rapid ephemerides are selected to expedite the data preparations of relative positioning. The influence of the first order single difference ionospheric path delay is eliminated by constructing single difference ionosphere free combination. Experiments of relative positioning are carried on the one-week observation data of the gravity recovery and climate experiment (GRACE) satellites. The result validated by K-band ranging system (KBR) observation data is 7.05 mm, which is equivalent to the precision obtained by IGS final ephemerides. It proves that this method can be used to realize the rapid relative positioning for long baseline satellite formation at mm level.