The Research Of The Theory And The Method And The Application Of Precise GPS Height Surveying

In this dissertation, the theory and the method of GPS precise positioning and data processing in monitoring the earth's crust deformation are systematically discussed. The main research contents of this dissertation are summarized as follows: (1) The basic theory of GPS positioning~ the method of GPS precise positioning and the source of its error are briefly introduced in the paper. Difference GPS technique can effectively eliminate the error of many physics?factors to GPS result, but can not effectively eliminate the error of the tropospheric refraction to GPS height. Therefore, the key to improve the measuring accuracy of GPS height is how to deal with the error of the tropospheric refraction. The methods of stochastic process (such as one-order model of Guess-Marlkov, the piece wise linear method) used for simulating the error of the tropospheric refraction are studied in detail. Both methods above can effectively eliminate the error of the tropospheric refraction to GPS result, and can obviously improve the accuracy of GPS height. The result by the piece wise linear method bears relation to the numbers of additional parameter in adjustment. After being tested and studied with one project, it is proved that the result of adjustment is good, if we use one additional parameter per 2 hours or per 4 hours to simulate the error of the tropospheric refraction. (2) The basic theory of neural network and an algorithm of BP are described in this paper. Many improvement steps to the problems existed in the algorithm of BP are put forward by the author. Putting a simple model (Model [2× 2×2]) of three-layer BP network as an example, all the formula for the algorithm of BP are deducted. A new structure of five-layer BP network used for converse GPS height is put forward in this article, and the optimal structure of the BP network is acquired after hundreds of tests. Normally, the conicoid fitting method (CBt) and the neural network method (NNM) are used for converting a GPS height into a normal height. But, each of them has its own advantages and disadvantages. After studying these two methods, a new method named Mixed-ethod (abbr. CF&\NM) is conceived that combines the advantages of both the conicoid fitting (CFM) and neural network method (NNM). The thought of the Mixed-method is an originality idea, and the effect of the new method is very good in the application of some projects, then the essence of the Mixed-method is analyzed. Comparing with the conicoid fitting method (CFM) to converse GPS height, the accuracy of the transform result with the CF&NNM method can improve 20 percent. The new method is worthy of extending. Otherwise, a betterment algorithm of BP network, named "error grade iterative method",is innovated by the author. By using the betterment method, the study convergence speed of network can be accelerated, the error of the simulating result influenced by the first weight and by the sequence of samples can be overcome, and the performance of BP network can be improved. (3) In the research of dynamic model of the erustal deformation, a model of kinematic adjustment of indirect observations has been established in this paper, its main adjustment formula has been deduced, and the relationship bet-ween static separate adjustment and the kinematic adjustment has been discussed. The current formula of the dynamic adjustment's error equation of observations united level net and GP...