When surveying inaccessible points with a total station or a GNSS, some special indirect methods might be required. The objective of this report is to find suitable special indirect methods for specific surveying cases; furthermore, some recommendations for the methods are given.
This report covers the remote elevation measurement method (REM), the double survey station method, the double-side survey method, the two prism method and the bearing and distance method.
These five indirect methods are carried out either with a total station or with a GNSS. The theory behind each method is given and their measurement uncertainty is analyzed from a numerical and a practical point of view. The findings are: the REM method should be preferred for remote objects, the two prisms method or the bearing and distance method for close objects where the ratio between the two participating distances should not exceed 2, a derived and simplified formula for finding uncertainties of bearing calculations is recommended
Source: University of Gävle
Author: Zhuo, Yue