GNSS Multipath Errors Mitigation Algorithm Based on Observation Domain for Landslide Deformation Monitoring

Abstract

Abstract The Global Navigation Satellite System (GNSS) real-time kinematic (RTK) technology is widely used for landslide deformation monitoring due to its precision and simplicity of its algorithm. However, GNSS signals are susceptible to multipath effects under complex circumstances such as terrain and surrounding vegetation. Reducing the impact of multipath errors and improving the RTK positioning accuracy is vital in ensuring accurate landslide monitoring in mountainous regions. The traditional method based on sidereal filtering in the coordinate domain only considers comprehensive multipath errors of all satellites, and the calculated time shift of coordinate sequence is not very accurate. In this paper, a sidereal filtering algorithm based on the double-difference residual in the GNSS observation domain is used for mitigating the multipath errors of landslide deformation monitoring in mountainous regions. First, we calculate the double-difference residuals of the observation in the previous cycle. Next, the empirical mode decomposition (EMD) filtering is used for denoising double-difference residual sequences. Based on the calculated period of the respective satellite, we use the residuals to correct the double-difference observation equation. Subsequently, we obtain the clean double-difference observations after mitigating multipath errors. Finally, the baseline coordinates of all monitoring stations can be calculated. The experimental results show that this method effectively improves the accuracy of GNSS landslide deformation monitoring in mountainous regions and the improved effect exceeds the traditional sidereal filtering algorithm in the coordinate domain.