What Is Gyrotheodolite Orientation?

The measurement of directional edge azimuth determined by gyro theodolite is referred to as gyro orientation. Due to the manufacturing defects of the overhead gyro theodolite, the gyro axis wobble balance position (called the direction of gyro meridian) observed through the eyepiece does not coincide with the true meridional plane of the passing station, so only the gyro azimuth Angle based on gyro meridian can be measured. The azimuth Angle of a gyro is obtained by measuring the difference between the direction value of the gyro meridian and the direction value of a certain side.The difference between the azimuth of a gyro and the true azimuth of a certain side (namely the dihedral Angle between the meridional plane of a gyro and the true meridional plane) is called the instrument constant.The instrument constant should be measured for each orientation;The azimuth of gyro is measured on the directional edge, and the coordinate azimuth of the directional edge is calculated.