The effect of weights observation to estimate the monitoring control point coordinate at sermo dam

The use of weights observation was effected on the estimation of coordinates and its precision. This research aims to identify 3D coordinates and its precision using weights observation from the result of GAMIT processing and the law of error propagation in sequential adjustment method. This research uses GNSS observation data from 10 deformation monitoring control points around Sermo Dam that was measured on doy 250 in 2014 and doy 129 in 2015. Data processing was performed by GAMIT software to get a baseline length and its precision. Baseline length and its precision were used as input in the sequential adjustment method. The values of weight observation were calculated using the result of GAMIT processing and the law of error propagation. The result of this research are 3D coordinates control point and its precision. The coordinate results using weight observation from GAMIT result does not significantly different from the law of random error propagation result, whereas the precision result is different significantly. The differences of precision reached 2 centimetres.