Using Technology Of GNSS To Determine Earth Rotation Parameters

Earth rotation parameters(ERPs)play an important role in geophysics, astronomy and other disciplines.First,earth rotation parameters are necessary when establish celestial reference system and earth-fix reference frame. Secondly, earth rotation parameters play a role of communication in the conversion of these two reference frames.Furthermore, it’s inextricably linked with satellites and spacecraft precision orbit determination and navigation.Compared with other technologies of space, global navigation satellite system(GNSS) has obvious advantages in the spatial and temporal resolutions.It can be all-weather, continuous observation.It’s equipment can move easily, the cost is low, and also the observation is high-precision It is an important technology to solve the Earth’s rotation parameters.Mutli-system is under use.The combination of multi-system data processing will further improve the accuracy of navigation, positioning and orbit determination.With the establishment of the Beidou navigation system and it’s formal operation,utilization of Beidou navigation system to determine the Earth rotation parameters is particularly urgent and important.The main contents are as follows:1. To judge the accuracy and reliability of using Beidou system to determine Earth Rotation Parameters,we based on least squares with constraints, using the data of Wuhan Beidou experimental network with the method of track difference of overlapping arcs to determine ERP and orbit.At the same time we do another experiment with the same state of our country’s land network of GPS data.We calculate the navigation orbit and ERP.Then we compared the result of the two. The result showing the accuracy of the pole motion parameter calculate by BDS is lower than the GPS results.But the accuracy of LOD is much better than that determined by GPS.2. We used the data of MGEX network, when we did the experiment we regard three days as a arcs. First given the result of ERP,separately calculated by BDS and GPS single system.Then analysis the two of them. Taking into account of the basis of GPS/BDS we obtain ERP results with the method of GPS and BDS jointly.In this method we give the result of ERP with different weight.3. To use the data of regional network to determine the satellite orbit and ERP has its limitations.So in this paper we use global GNSS network data to determine ERP. When use GLONASS data to determine ERP, we applying a loose constraint on orbit and ERP, and applying a strong constraint on the station. Similarly, the same method is used when using GPS data to determine the ERP. The result shows the orbit precision of the former significantly lower than the GPS orbit.4. Using GPS and GLONASS data united to determine the GPS satellites orbit,at the same time analysis it’s accuracy.Then is GLONASS satellites orbit.Meanwhile joint GPS / GLONASS technology to determine ERP. The results showed that with respect to the determination of GPS the accuracy of length of day and pole motion parameters are not improved, but slightly declined.