虚拟球谐方法逼近市级大地水准面计算分析

Analysis of Virtual Spherical Harmonic Method Approaching Small Area Elevation Datum

研究了构建市级大地水准面的虚拟球谐方法。首先,选择构建区域的中心点和区域半径对观测值进行数据预处理,并统计分析数值范围和位置信息;然后,将观测值由地理坐标系转换到球冠坐标系,再转换到虚拟球坐标系中;最后,根据虚拟球谐方法构建市级大地水准面。以南昌市为例构建采样点,采用多项式拟合和神经网络方法与本文虚拟球谐方法进行比较分析,结果表明,虚拟球谐方法的RMS值为0.308 cm,拟合效果最好。

This paper studies the theory and method of constructing virtual spherical harmonic of municipal geoid.First,we select the center point and radius of the build area.Then,the observed data are preprocessed,and the numerical range and location information of the observed values are statistically analyzed.Secondly,the coordinates of the observed values are transformed from geographic coordinates to spherical crown coordinates,and then to a virtual spherical coordinate system.Finally,the municipal geoid is constructed according to the virtual spherical harmonic method.The polynomial fitting,neural network and virtual spherical harmonic method are used to construct the sampling points in Nanchang City.The results show that the virtual spherical harmonic method has the smallest fitting RMS value,which is only 0.308 cm,and the best effect.