Abstract
Regular monitoring of dams is fundamental to ensuring their safety, stability, and smooth operation. However, during the measurement phase, a number of obstacles are encountered that are often difficult to predict at the planning stage of the observation campaign. In such situations, the surveyor must decide whether to continue all planned observations, which may involve a significant extension of working time. An alternative is to reduce the number of observations deliberately, provided the required accuracy and reliability of the data are ensured. This paper examines the impact of missing observations on the position errors of control network points. Using an angular-linear network as an example, a simulation was carried out by excluding observation stations selected at random from subsequent adjustments and by checking its effect on the final result.
Additionally, the possibility of removing from the adjustment those observations that were considered problematic for measurement due to various types of obstacles was verified. The results of the conducted studies show that the cautious station elimination prevents network weakening. The necessary removal of problematic observations can be implemented already at the measurement stage. These findings highlight the significant trend of decreasing accuracy in determining the positions of network points. After eliminating 15% of the observations, the control network maintained high accuracy, with the resulting RMSE changing by no more than 10%.