Abstract: In order to strengthen the direction control of underground wire, reduce the cumulative effects of angle-measuring error by long-distance penetrative wire and ensure transfixion precision, the Gyro-theodolite is used to orient the downhole traverse sides. The paper introduced Switzerland WILD GAK-1 Gyro-theodolite, and presented a case to orientate downhole traverse by reversal point method of Gyro-theodolite. This method improved the directional precision of roadway and analyzed some issues in the orientation. 

Key words: Gyro-theodolite, Reversal point method, Orientation error, Orientation precision