The method of the system error modification Of photoelectric theodolite of T type

The system error of photoelectric theodolite includes Visual axis error, horizontal axis error, vertical axis error, Azimuth orientation error, elevation zero error; This paper ratiocinates the formula of Azimuth orientation error, elevation zero error and Visual axis error of Photoelectric theodolite of T type by triangle relation in space. Photoelectric theodolite of U type with main visual axis and auxiliary visual axis shoots images and inverse images of marks to obtain system error data. Error is less than 0.4 second by comparing error data of auxiliary visual axis with error data of main visual axis and the precision of two methods is identical. It has been validated that the method of error measurement of photoelectric theodolite of T type is right.