Research On GPS Control Measurement Theory And Method For Geophysical Prospecting

Survey Technology for Petroleum Geophysical prospecting is a special engineering technology for geophysical exploration;it solves the survey line design,stake out operation and surveying work in oil geophysical prospecting.And it provides the reliable receiver location and shot point position for exploration.The control survey for Petroleum Geophysical prospecting provides a coordinate datum and basic control network for the prospect area.In this paper,the basic theory and method of the control survey for Petroleum Geophysical prospecting are described,which is based on the traditional traverse survey,GPS control survey and data processing method.In view of the problems of oil exploration under the condition of the lack of control point and in bad preservation,a high precision GPS control network is proposed,which is based on the GPS leveling and the GPS height control survey.In view of the layout of seismic survey lines in petroleum exploration,the field survey and data processing method for traverse survey and GPS control survey meet the required accuracy are analyzed.According to the error theory in GPS positioning,via satellite positioning observation equation,the impact including inaccurate initial coordinates,ephemeris,ionospheric propagation delay and tropospheric refraction on baseline precise computation and the corresponding treatment measures are discussed in the paper;And the paper introduces the GAMIT software be used in long baseline GPS control network and known fixed point constraint adjustment method or the known points weighted adjustment of is proposed in this paper to perform the network adjustment.In view of the problem of the variation of the height anomaly in the local area in the height control survey,a surface fitting method based on robust estimation is proposed,which is applied to the oil geophysical prospecting.Analysis and comparison of different fitting mathematical model and quasi-land-level model in the petroleum geophysical survey were carried out and it achieved a centimeter-level fitting accuracy.