Application of GPS leveling fitting model

This paper mainly focused on statistical analysis by different fitting model of Beijing section data in South-to-North Water Transfer Project. The results indicated that the GPS leveling height were different compared with leveling method, and by using the initial data with the same number and the same group data. Therefore, GPS standard model were used by test method and the results were reliable. The results demonstrated that the average difference value was 0.00013m, the maximum difference value was -0.02133m, and the root-mean-square error (RMS error) was 0.00258m inside residual error. The outside residual were as follows, the average difference value was 0.00193m, the maximum difference value was -0.05631m, and the root-mean-square error (RMS error) was 0.01453m. It is also discuss the three methods to improve precision.