Stability analysis method for deformation monitoring network based on variance covariance matrix

The invention discloses a stability analysis method for a deformation monitoring network based on a variance covariance matrix. The method comprises the following steps of (1) performing two phases ofobservation on a GNSS control network to solve a baseline of the whole network; (2) determining a stable direction and a stable point; (3) obtaining XY coordinates of each control point in the two phases of observation based on the adjustment of the stable point and the stable direction, obtaining a displacement amount deltaP and a variance covariance matrix DXY during the two phases of observation, and calculating an error mdeltaP in the coordinate difference based on the variance covariance matrix DX of each control point; and (4) determining each of the control points: determining that thecontrol points are stable if |deltaP| is less than or equal to 2mdeltaP. The method is rigorous in theory, and determines the most stable baseline by taking the minimum relative length change as criterion, and accurately dete