Based On The Law Of Gravity And The Combination Of Gps Leveling Geoid Of Study

Precise determination of local geoid is the importing issue of some field .such as geodesy and geophysical .and so on. And same time, it also is a import project of base map up date, Regional geoid determination with centimeter-level precision is the geodesy research hotspot. It will provide multi-disciplinary research and application such as base map up date ,digital China geo-spatial framework, local monitoring on settlement .environment forecast ,disaster prevention, national defense construction, ocean science, weather forecast, earth science research, traffic, water resources, power with essential mapping service, has significant scientific significance and tremendous economic and social benefit.At first the article describes basic theory and principles of precise determination of local geoid. Then discuss and make a research about geometrical method and gravity method at length, respectively. In the geometrical method ,compute and analyze the applicable area of the moving curved surface fitting, multiple curved surface fitting, Neural Network(NNT), compare the precision and applicable area; in the gravimetric method, using example, compute and analyze the precision and trait of the coefficient expression which determine the gap of the geoid, according to the trait of the coefficient expression, discuss it combined with the other method: it combined with NNT can enlarge the applicable area of the latter; make a research about the standard algorithm which precise determination of local geoid, i.e. remove-restore, include the route and approach and mathematic model. We applied all available data which come from the region in east china area: the eastern longitude 117°~118°,the northern latitude 26°~27.50°, 8153 gravity point , lkmxlkm DTM grid , EGM96, 36 GPS/ leveling production, based on the above theory, use Chinese new successful experience for reference, computer the terrain correction and isocratic correction with FFT technology, computer the residual geoid with stocks formula, then add it up with of the geoid of the geopotential model, then fit it with the GPS quasi-geoid, finish this Regional geoid, with ±3 centimeter-level precision at last.