Integrated surveying method for FOG inclinometer aided by cable length

In order to realize long-term surveying with high accuracy of fiber optic gyroscope (FOG) inclinometer, according to the logging operation, an integrated surveying method based on Kalman filter technology was proposed, which was aided by cable length information. The error model of inertial surveying system (ISS) and the measurement model of the cable length were introduced. The overall scheme of the integrated surveying method was designed. Meanwhile, the error state-space model of the integrated surveying system and the measurement update model were established. The proposed method was validated by semi-physical simulation. The simulation results show that, during 14 400 s simulation process, inclination angle error is less than 0.02°, toolface angle error is less than 0.12°, azimuth error is less than 0.98° and the position error is less than 47.5 m. Compared with the pure inertial measurement results, surveying errors can be reduced effectively, the long-term surveying precision is guaranteed and the performance of the instrument is improved.