Attitude measurement and error compensation for horizontal directional drilling

Measurements of the drill bit attitude during drilling are the key for steering of horizontal directional drilling.An approach was developed to determine the inclination,the azimuth,and the roll using three mutually orthogonal accelerometers and magnetometers.The system includes compensation for the temperature error and the orthogonal error.Error compensation is also included to compensate for the azimuthal error due to the magnetic field interference generated by the drill which affects determination of the geomagnetic inclination and geomagnetic declinations.Test results show that these methods significantly improve the attitude measurement precision.