Abstract
Control point surveys by the conventional method entail an enormous amount of work and time, since it is necessary to cut down trees from a national control station which may be dozens of kilometers away. This study discusses an easy, highly precise method of control-point surveying based on the GPS (Global Positioning System). Through series of experiments, many of the problems which were hampering this new method have been solved, including major concerns such as the position of the artificial satellite, the survey time, and the baseline analysis method.
This unique new surveying system is now fully established and has proved effective in actual surveys. Succesful results have been obtained at three tunnel construction sites, where a precision of more than 1/1000000 was achieved.
