配置法在局部大地水准面精化中的实例研究

从最小二乘配置方法的基本原理出发,以我国某地区范围内1km分辨率的大地水准面高模型数据为例,根据实用公式计算了试验区大地水准面高的协方差值后,采用多项式函数模型和高斯函数模型分别拟合了该地区大地水准面高的局部协方差函数,并对试验区内18个检核点做了推估计算。根据推估值(Nfit)与实测值(NGPSL)的比较分析表明,虽然多项式协方差函数模型略优于高斯协方差函数模型,但它们都能以厘米级的精度拟合局部大地水准面,这表明了配置法用于精化厘米级大地水准面的有效性。

Application of Least-Squares Collocation to Fitting the Local Geoid

Based on the theory of least-squares collocation (LSC), we use a 1km resolution of local geoid model as test area, and choice a practical formula to compute the covariance of geoid height. With the covariance of geoid height, two function models (polynomial model and Gauss model) are used to define the local geoid covariance function respectively in this paper. To evaluate the effectiveness of the local covariance model, the geoid heights computed by LSC are compared to those derived from GPS/leveling at 18 checkpoints. According to the results, both of the two models can fit the local geoid with centimeter level, though the polynomial model is better than the Gauss model. The test results demonstrated that the least-squares collocation is very useful and effective in the refinement of local geoid.