Application Of The Ellipsoid Expansion Method To Establish Independentcoordinate System In Highway Engineering

In recent years, due to the rapid economic development, the traditional geodesic survey cannot have satisfied economic development needs, especially in the way of measuring method of measurement of the traditional because of its low efficiency, the poor precision, long term to test shortcomings now rarely used. With the continuous improvement of the GPS positioning accuracy, GPS technology in the application of road engineering is more and more extensive, no matter from the road of survey and design, the construction site, or on the bridge control survey, GPS measurement technology plays a tremendous role, however, GPS measurement of most used is tight WGS-84coordinates, and in the city measures or engineering control measure, of the actual use of the plane coordinate system is, based on this, how will WGS-84coordinates efficient and accurate, convenient to plane coordinate transition has the important practical significance.Coordinate system is the foundation of all measurements, the accuracy of the coordinate system directly affect the quality of the construction project. Establish independent coordinate system in the process of GPS data due to after two domestication, when measured at the higher the area or from the central meridian projection distance, the greater the error of the naturalization produce, this will affect the quality of the whole project. This paper establish independent coordinate system created during the length deformation, combined with a Yellow River bridge in Inner Mongolia GPS control network, the impact of establishing the independent coordinates of parameters, conditions is studied and analyzed, and the main research contents include the following aspects:(1) to our country commonly used coo. dinate system of a simple classification and introduced in this paper, the earth of the ellipsoid geometric parameters and mathematical model of the theory of national coordinate system, establishing the method of research and analysis, establish independent coordinate system is deduced the mathematical model.(2) for the GPS data processing in the simple introduction, through the use of different ellipsoid parameter set up different independent coordinate system, and a Yellow River bridge in Inner Mongolia GPS control network of measured data in the test, verified by the accuracy of the establishment of the independent coordinate system.(3) This paper focus on the WGS-84coordinate system independent coordinate system to the transformation of the system, the complicated computing process simplification, which realize the coordinate transformation programmed, the results of the evaluation of conversion and the error analysis, it is concluded that the establishment of the independent coordinate system optimal parametersThis thesis research results show that: to establish independent coordinate system only changed when reference ellipsoid Hm or only changed the central meridian established Ym mobile coordinate error in far greater than also change the error in the Ym Hm and value; At the same time change both the value, the choice of the area through the meridians as the central meridian center from the error of some smaller.