Design of an Underground Attitude Measuring Sonde for Directional Drilling Locator

Exact attitude information of the boring tool is a fundamental factor in underground directional drilling. According to the requirement of directional drilling, a special attitude measurement method based on 3-axis accelerometers and 3-axis magnetometers is described, and the azimuth, the pitch and the roll angles are derived. The entire configuration is designed, and an actual sonde system is established by adopting low-cost MEMS micromachined polysilicon accelerometers and MEMS magnetoresistive magnetometers as basic sensors. The system performance is improved by some unique techniques, such as temperature compensation and azimuth correction. Final results show that the MWD system can get the real-time pitch, roll and azimuth while drilling, with the accuracy of 0.7, 1.0 and 2.0 degree. It has the characteristics of good performances and low cost, and it is suitable for industrial application.