Abstract: With the development of fully automatic intelligent total station and the gradual elimination of optical level,precise trigonometric leveling has been widely used in river-crossing elevation transfer.This paper detailed the principle and steps of quadrilateral river-crossing leveling method based on precise trigonometric leveling with fully automatic total station.In addition,this method carried out theoretical derivation and precision analysis of the height difference between river-crossing points obtained by directional observation,and it was proved that this method could be used in the second-class river-crossing leveling under the condition of controlling a certain cross-river distance and taking corresponding measures to eliminate other errors.Finally,an experiment showed that the method could meet the accuracy requirements of second-class river-crossing leveling.

Key words: autocollimation total station, precise trigonometric leveling, quadrilateral, error analysis