抗差自适应拟合推估技术在似大地水准面拟合中的应用

Application of robust adaptive colloction method to quasi-geoid

拟合推估法用于似大地水准面拟合时会遇到观测噪声和信号之间权比的不协调,导致观测权阵和信号向量的权矩阵比例不合理,将直接影响固定效应参数和随机信号参数的估值。当观测值含有粗差时,会使结果严重扭曲。基于此,文中将抗差Helmert方差分量估计用于似大地水准面拟合中,可自适应调整观测噪声与信号之间的权比,同时又可抵御粗差的影响。采用某山区的实测数据进行试算,外符合检验结果表明:采用自适应拟合推估法构建的似大地水准面外符合精度较正常拟合推估方法提高1cm多,且解较稳定。同时,抗差自适应拟合推估不仅有效抵御粗差的影响,而且可以调整二者权比,结果更加合理。

The collocation method applied to quasi-geoid will meet the ration of prior covariance matrix between signals and observations, which results in the unreasonable weight between observations and signals and twisting the solution of collocation. When the observations are contaminated by gross error, the result will be distorted. A robust helmert estimation of variance components in used in the collocation, which will adaptively adjust to the ration of weights and degrade the effection of the gross error. With the observed data in one mountain area, it shows that this adaptive method can improve the accuracy of quasi- geoid by more than 1 cm and the solution are more better stable than normal collocation. The robust adaptive collocation not only resists the effection of outliers, hut adjusts to the weight ration. The result will be more reasonable.