Comparative study on wavelet analysis and empirical mode decomposition for BDS multipath error reduction

When using BDS for high-precision deformation monitoring, the multipath effect generated by BDS signal is a non-negligible error source that affects the accuracy and reliability of deformation monitoring data. The BDS has three different orbiting satellites, and the resulting multipath error is more complicated. Multipath error based on coordinate domain uses wavelet analysis (Wavelet) and empirical mode decomposition (EMD) for original sequence denoising, and advanced sidereal filter (ASF) for denoising sequence for multipath error culling. The two methods improved the baseline accuracy by 38.6% and 40.8% in E direction, 59.1% and 61.0% in N direction, 57.8% and 57.9% in U direction, respectively. The empirical mode decomposition improved the smoothness of the coordinate sequence and the baseline accuracy better.