GPS高程拟合方法的对比试验研究

Experimental Research on GPS Height Fitting Method

GPS测量的高程是大地高,而我们日常使用的高程是正常高,这中间存在一个高程异常值,由于地球质量分布不均,这个高程异常值不是个常数。本文简要介绍了常用高程系统及相互的转换关系,重点介绍了多项式曲面拟合和多面函数拟合两种GPS高程拟合方法。结合北京市地面沉降监测项目,利用研究区范围内监测点已有的A级GPS测量数据和一等水准测量数据,采用了五种拟合方法,通过不同的选点方式,再经过MATLAB软件编程计算,对研究区进行了高程拟合,并对各项试验结果分别进行了拟合精度的评定。通过对每个拟合模型进行分析,对拟合结果进行比较和对五种拟合方法进行比较,最后得出结论,选择适当的高程拟合模型进行高程拟合能达到四等水准测量精度,采用二次、三次曲面拟合和多面函数拟合方法均能较好的对研究区进行高程拟合。

The height of the GPS measurement is the geodetic height, and the daily used height is normal height.There is a height anomaly value between the heights. This paper briefly introduces the common elevation system and the mutual conversion relation, and the common GPS height fitting method. Combined with the land subsidence monitoring project of Beijing city, this paper uses the Level A GPS measurement data and the Level 4 Leveling measurement data, through different selecting method, through the MATLAB software programming calculation, finishes the elevation fitting in the study area, and the test results are presented separately for the evaluation of the fitting precision. Through the analysis of each fitting model, the fitting results are compared and the five fitting methods compared to draw the relevant conclusions that choosing the better method can reach 4 Leveling measurement accuracy; the quadric surface, cubic surface and polyhedral function are the better height fitting methods to study area.