Analysis and Research of Extrapolation Accuracy with Interpolation Model Based on Network RTK

In network RTK the models extrapolation accuracy of spatial error is directly related to RTK position validity and reliability. So the extrapolation accuracy of coordinate linear interpolation model and distance linear interpolation model are studied in this paper. Firstly, according to the root mean square of interpolation coefficient of model and the law of errors propagation, two models stability and the factors which affected the extrapolation accuracy are analyzed from the relationship of the models linear function. Secondly, in different areas out of net the change regularity of extrapolation error is further discussed with types of data in different length baselines. The result shows that extrapolation accuracy of the above model are related to the net shape of network RTK, the estimation precision of the comprehensive error that exists between reference stations, and the distance that rover is away from the net. The extrapolation accuracy of the coordinate linear interpolation model is better than the distance linear interpolation model. In the areas that not more than 40km to the net external it can be reached within 5cm estimation accuracy of the extrapolation comprehensive error. It is helpful to rapid high-precision position out of the network.