Building Method And Application Research Of GPS Net In Special Exact Project

There are two important issues in establishing precise engineering control network: â‘  establish applicable coordinate system, so as to decrease distance distortion due to height difference and projection in construction â‘¡ dominate accuracy of control network . Presently, GPS positioning technology applied step by step to high precision network in precise engineering design and construction. Generally, we adopt GPS relative positioning techniques in precise engineering surveying. Two receivers observe the same set of satellites simultaneously then give the relative position between terminal points of a baseline. This solution help to reduce satellite orbit error, satellite clock error, receiver clock error and error due to ionospheric refraction and tropospheric refraction, therefore, give enhanced position accuracy. GPS network simulation design and accuracy estimate may be carried through, It assist the GPS network that will be established meets the accuracy requirements in construction.This thesis focus on GPS application in magnetic suspension engineering: â‘  the formulation of oblique cylindrical projection is worked out according to characteristics of long distance precise engineering and map projection theory. The author has developed an application to accomplish coordinate conversion from generally used coordinate systems to oblique Maglev Coordinates System. â‘¡ considering not only project peculiarities but also position of control points, selection of initial points, connection type, selection of repeat baseline and ground observed quantities, GPS network is designed on electronic map and we may extract GPS network information by program developed using Visual Basic 6.0 while the results are stored in control point file and baseline vector file. â‘¢estimate accuracy of various GPS networks designed on electronic map by method of 2D restriction adjustment. GPS network simulation design and accuracy estimate come true. â‘£Predominate the rules how connection type , repeat baseline and precise baseline of range finder influence GPS network precision through comparing accuracy of various GPS network. Thereby, the solution how to establish GPS network in long distance precise engineering is figured out.