Gps Data Processing And Its Slope Subsidence Monitoring Applications

GPS surveying is a process by which highly accurate, three-dimensional point positions are determined from signals received from satellites. GPS-derived positions may be used to provide the primary reference control monument locations for engineering and construction projects, from which detailed site plan topographic mapping, boundary demarcation, and construction alignment work may be performed using conventional surveying instruments and procedures. GPS control surveying techniques are also used for the rapid, real-time geospatial feature mapping of wetlands, facilities, utilities, and related geographical information system(GIS) products.With the development of satellite-orientate technique and the adjustment of American GPS's policy, the technique of satellite-orientate has been come into used all over the world. Now, GPS' action gets more and more important in wide range high-precision survey control net,city control net,project control nets survey map control net.This paper analyzes system error and accidental error by GPS in surveying, studying methods of improving the accuracy of GPS geoids height. The data of GPS geoids height handled in a reasonable manner is convenient for reflecting true situation in adjacent two monitoring periods of vertical displacement. The purpose is solving the problem of vertical displacement accuracy in deformation monitoring by GPS.