Study of normal height difference fitting method of GPS river-crossing leveling

摘要

This paper introduces a fitting method that adopts geodetic height differences and leveling height differences of the GPS-leveling points on both sides of the river to calculate the normal height differences between the river-crossing points. Simultaneously some fitting models are put forward and discussed. This method avoids the disadvantages of the general height fitting methods that request the same height datum for both sides of the river and only could be extrapolated from known height points, therefore advances a new, simple and effective way to resolve the problems of river-crossing leveling in difficult areas such as mountains, canyons, islands etc. Compared with the general river-crossing leveling methods, the accuracy and efficiency of the new method are greatly improved. Finally, some helpful conclusions are drawn based on analyzing the experimental data from the test which was done in the city of Nanchong, indicating that by adopting GPS-leveling method to do the river-crossing leveling, if the rational fitting model has been used according to the concrete conditions of the river-crossing field, the precision can be absolutely achieved, and even superior to that determined by the general river-crossing methods.