Application Of Base On The EEMD Method In Multipath Effects Of GPS Deformation Monitoring

As is well known, because of the influence of self structure and external factors, the building will have a certain degree of deformation which come from the building construction and use of buildings.This is a big risk for the stability and safety of buildings.Therefore, it is necessary to monitor the deformation of building. GPS has Some advantages in the deformation monitoring, for example high precision, all day observation and survey station do not need intervisibility.These advantages make GPS becomes an advanced measuring method in deformation monitoring. In actual GPS deformation monitoring, measurement accuracy can be affected by many factors. Short baseline is often used in deformation monitoring via the differential model toeliminate the error. But this method can not eliminate multipath effect and random noise.This paper has research on this problem and the research contents are as follows:(1) Research the background and development status of GPS deformation monitoring and multipath effects and analyses the advantage and disadvantage of them.The Ensemble Empirical Mode Decomposition(EEMD) method is introduced in this paper, which is based on the mode mixing phenomenon in Empirical Mode Decomposition(EMD) method.The simulation signals are decomposed by two methods, and the experimental results show that the EEMD is suppressed in a large extent by the EMD.(2) Two denoising methods based on EEMD combined with wavelet threshold and EEMD in combination with Independent Component Analysis( ICA) are introduced.The experimental results show that the algorithm has good effect of denoising.After the above methods using GPS coordinate residuals to measured solution, experimental results show that these methods can play a role in weakening the multipath effect, the EEMD combined with ICA method had the best effect.(3) A multipath error correction method based on EEMD combined with principal component analysis(PCA) is proposed.Through the experimental data analysis results show that this method can effectively improve the precision of position, and have certain advantages.