Gps multipath change detection in permanent GPS stations

We have proposed a technique based on an adoptive filter using the least-mean-square algorithm for detection of multipath change in permanent, continuously operating GPS (CGPS) stations. We have tested the technique on some experimental data, indicating that the multipath change smaller than the receiver noise level will go undetected We have also conducted further tests with sonic CGPS data from the Japanese GEONET when there was a snowfall, The results show that is hen there is a change in the antenna environment it will indeed be detected in both the pseudo-range and carrier phase data, This technique provides an easy-to-implement, quality, assurance tool for CGPS antenna environmental sensing after events such as typhoons, cyclones, snowfalls, volcano eruptions, earthquakes, etc, Other possible applications include the monitoring of slope stability and ground subsidence.