Accuracy Analysis of Earth Rotation Parameters Combining with VLBI Observations in CONT17 and GNSS Observations

Abstract

The Earth rotation parameters (ERP) mainly including the displacement and rate of the earth's poles, UT1-UTC, length of day are estimated by processing the thirty-one IGS stations data from November 28, 2017 to December 12, 2017 with GAMIT. The ERP are obtained with VieVS3.2 by processing VLBI data observed on CONT17 campaign. The ERP results of GNSS and VLBI are combined in a weighted way, based on the Helemert variance component estimation and weighting method is proposed. The results show that the Root Mean Square(RMS) of the polar shift component in the X-direction is 0.000985 mas, the RMS of the polar shift component in the Y-direction is 0.000286 mas, and the RMS of UT1-UTC is 0.000690 ms, and the weighted accuracy is significantly better than that of the separate solutions of GNSS and VLBI, which can make up for the shortcoming of the single technique as GNSS and VLBI.