Regional GPS Deformation Monitoring Data Processing Method

The deformation monitoring is an important method to monitor the security of deformation body. Our exploitation of natural resources breaks the balance of the upper part of earth crust and leads to the ground deformation. If without long-term monitoring and supervision of these areas, and without timely solutions to control their deformation, the ecological environment in the mining areas will suffer serious damage. With the development of GPS technology, especially the precise baseline solver software improvement and the establishment of IGS tracking stations provided favorable conditions in large mine deformation monitoring.This paper based on the GPS monitoring work of deformation, combined with the experience that it is difficult to find a stable reference point in large mine. Using GAMIT software to process IGS tracking stations and large mine deformation monitoring data, and the result proved the feasibility of IGS tracking stations as large regional deformation monitoring reference datum. Researching and proposing a new method which is used to detect reference point stability. This paper covers the following aspects:1) Summary on the errors of GPS in monitoring deformation and brief study of gross error.2) Discussion on the choice, determination and unification of references in deformation monitoring network. Had depth research on theoretical knowledge of free adjustment, including the fixed datum, the center of gravity benchmark and approximate steady benchmark as well as the corresponding classical adjustment, rank defect free adjustment, approximate steady adjustment. Getting apply the three adjustment methods on engineering projects.3) Had research on the issue of reference data in deformation monitoring network, and derivation of conversion relation result in different free network adjustment reference. At last, brief introduction of several coordinate conversion methods.4) Research of the method to analyze point displacement in deformation monitoring network, and discussion on the improved mean spacing method in detail. Proposing a new improvement——the average gap method of three-dimensional coordinates.5) Application examples of the theoretical methods in this paper to monitor deformation in Huaibei Mining Area. GPS observation data of the deformation monitoring network in each period will be processed by GAMIT software, thus gaining adjustment result of monitoring point coordination under various adjustment references, and analyzing its unity. It will analyze the stability of monitoring points, getting conclusion that surface of mine had occurred subsidence and displacement. And analysis the stability of the country’s GPS C grade points in the mine, getting conclusion that they had obvious displacement, thus are not suitable to be reference point.