The instrument is made up of ground system, downhole survey assembly and the software, the ground system connect with downhole assembly through wrench, the downhole assembly including battery for power supply.North Seeking Gyro system is designed to seek north automatically, it adopts high precision gyro and accelerometer sensors, and there is no need to calibrate on ground, It is free from magnetic interfere and measure the inclination, true azimuth and northward tool face, Gravity high side etc. with the software, the data can be collected and stored based on the interval set up in advance and get the trajectory of the well body. In the drilling industries, this instrument is applicable to: check the. well body quality in casing, orientation jobs in multi-branch
wells, casing and open
