Underground orientation method based on rotating magnetic field

Abstract

An underground orientation method based on rotating magnetic field includes: installing horizontal cylindrical permanent magnets on a nonmagnetic turntable with a vertical rotating shaft to form a ground artificial magnetic field generator, installing a measuring unit composed of a triaxial accelerometer and a triaxial magnetic field sensor in an underground drill rig, measuring to obtain magnetic induction density of a point in space first, allowing the permanent magnets to rotate around a Z axis when the drill rig is stationary, stopping rotation at intervals of certain angle during rotation, recording values of three-directional magnetic induction density, subjecting the values of the magnetic induction density to coordinate transformation according to current tilt of the drill rig and face angle of a tool, performing curve fitting to obtain coordinate value restraint relation, performing coordinate transformation and curve fitting again to obtain two sets of coordinate values, and if differences between the two sets of coordinate values are within the error allowed range, confirming coordinates of the drill rig in a reference coordinate system and confirming current azimuth angle of the drill rig. The underground drill rig can be guided and positioned accurately by the underground orientation method, and the requirement for orientation in underground works such as horizontal directional drilling is met.

Description

technical field [0001] The invention belongs to the field of information science, can be applied in the process of horizontal directional drilling to accurately guide and locate underground drilling tools, and can also be applied to other underground guidance or positioning projects, and relates to an underground guidance and positioning method based on a rotating magnetic field. Background technique [0002] With the development of my country's economy and the acceleration of urbanization, the horizontal directional drilling technology that does not need to excavate the ground has been more and more widely used. In horizontal drilling technology, how to accurately guide and position the drilling tool is the key to realize horizontal directional drilling. At present, the commonly used methods are orientation based on the geomagnetic field and ground tracking orientation. [0003] Among them, the measurement-while-drilling system based on the geomagnetic field does not requi...

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