关键词: 控制网, GNSS, 控制点稳定分析, 方差-协方差阵, 坐标较差法

Abstract: In order to study and analyze the stability of measurement control points in hydraulic engineering constructions, this paper proposed a stability analysis method based on variance-covariance matrix for coordinate difference method, and derived the calculation model. At the same time, taking the two-phase GNSS observation data of Baolin tunnel as an example, the control point coordinates and its variance and covariance were obtained through the control network adjustment. The calculation results were given by the presented method of this paper, and compared with the existing coordinate difference method. The result showed that the RMSE calculated by the existing coordinate difference method is significantly larger than the RMSE by the variance-covariance matrix method because the existing method does not consider the influence of covariance. And the influence of the covariance of the control point coordinate components on the RMSE can even reach 1/3 of the existing coordinate difference method. Therefore, the proposed method is more reliable to measuring the stability of the control points.

Key words: control network, stability analysis；variance-covariance matrix；coordinate difference method；Baolin Tunnel