基于曲面逼近的空间坐标转换方法

摘要

Realizing coordinates transformation between WGS-84 datum and local datum is the key problems of GPS surveying.It is difficult to obtain the precise geodetic height in the national or local coordinate system which affects the accuracy of 7 parameter mod-els.This paper puts forward a thought of curved surface approximation which can complete the WGS-84 to BJ54 and WGS-84 to Xi’ an 80 coordinate transformation combining with the method of height approach.It only needs to know the plane coordinate of each datum.The results of experiment show that in a certain longitude-latitude grid it is able to complete the high accuracy plane coordi-nate transformation to meet the demand of the actual work in the case of geodetic height unknown or inaccurate.%GPS测量的关键问题是实现WGS－84基准和地方基准之间的坐标转换问题。精确的国家或地方坐标系中的大地高很难得到，这就使得七参数模型的精度受到了影响。本文提出了曲面逼近的思想，只需已知两个基准的平面坐标，结合高程趋近法完成了WGS－84到北京54以及WGS－84到西安80的坐标转换。实验表明，在一定范围的经纬格网内，大地高未知或不准确的情况下，也能够完成较高精度的平面坐标转换，满足实际的工作需求。