Single Navigation Satellite Orbit Determination

Satellite navigation system is important spatial basic establishment, human can benefit from it tremendously. As a developing country, China has capacious territory and sea area, it's necessary for China to possess its own global satellite navigation system. After the GPS of USA, the GLONASS of Russia and the Galileo of Europe, China is preparing for its own global satellite navigation system called Compass Navigation Satellite System (CNSS).The orbit of navigation satellite is the basic element for positioning; it can affect the precision of user directly. The observation data for orbit determination is pseudo-range which includes satellite clock error and receiver clock error. With the aid of time synchronization system, pseudo-range is equivalence to range. Without the aid, if the receiver receives the signals from two satellites simultaneously, the clock error can be removed using the difference method at the same epoch.In some situation of navigation system, for example, there is only one satellite in early stages or some satellite was carded out orbit control or maneuver, we need determine the orbit of single navigation satellite. But the difference method at the same epoch can not be used to eliminate the clock error of the satellite or the receiver. Although the difference between two subsequent measurements can eliminate the dominant terms of clock errors, it only provides difference information of orbit, the geometry intensity of orbit determination is lower, the precision of orbit determination is not very good.In this paper the clock errors of satellite and receiver are analyzed, there exists an obvious linear item in them, and so the pseudo-range is equivalence to range with linear-change range. To verify the feasibility and accuracy of this strategy, we perform orbit determination using real GPS data. It indicates that it is better than the difference approach over time.The stability of the clock error of the second generation of CNSS would be better, considering that the frequency standard of the signal and the receivers for orbit determination is provided by atomic clock. We perform orbit determination using simulation data; it indicates that better precision can be expected using this orbit determination strategy for Inclinined Geosynchronous Orbits (IGSO) satellites and Medium Earth Orbits (MEO) satellites.It can't be used for the orbit determination of Geostationary Earth Orbits (GEO) satellites without the aid of time synchronization system. To determine the orbit we need synchronization system for two stations at least, to get better precision we need synchronization system for four stations at least.The IERS Conventions (2003) were implemented in the precise orbit determination software SHORDE of Shanghai Astronomical Observatory. The IERS Conventions (2003) define the standard reference systems realized by the International Earth Rotation Service (IERS) and the models and procedures used for this purpose. It is a continuation of the series of documents begun with the Project MERIT Standards (1983) and continued with the IERS Standards (1989, 1992) and IERS Conventions (1996). Precise orbit determination is performed for Lageos1 and Lageos2 using the updated software SHORDE, The result of the orbit determination shows that it is very finite for precision improvement.