Study on replacing the second, third and fourth order leveling by vertical distance measurement with total station instrument

This paper discusses a method of trigonometric leveling with total station instrument and vertical distance measurement. Based on the theory of trigonometric leveling and leveling, this method ignores the height of instrument and prism and measures elevation differences by observing vertical distance of foresight and backsight with the instrument placed at the middle of survey lines. It is shown that by theoretical analysis and experiment the method with many advantages can meet the needs of the second order leveling and replace the second, third and fourth order leveling in knap and low mountain areas.