Abstract: A rotating magnetic field range finder for measuring relative distance in drilling, comprising a permanent magnet steel drill collar (1), an underground detector (2) and a ground interface box (3). The permanent magnet steel drill collar (1) is fixed to the rear part of a drill bit and rotates together with the drill bit to generate a rotating magnetic field to provide a magnetic field signal source. The underground detector (2) comprises two tri-axial fluxgates and three accelerometers. The ground interface box (3) is used for processing the obtained data, and powering the underground detector. The permanent magnet steel drill collar (1) is an obliquely arranged one or a perpendicularly-and-parallelly assembled one. A measuring method for magnetic range measurement is also disclosed.

Abstract: A rotating magnetic field rangefinder for measuring relative distance in drilling, comprising a permanent magnet steel drill collar (1), an underground detector (2) and a ground interface box (3). The permanent magnet steel drill collar (1) is fixed to the rear part of a drill bit and rotates together with the drill bit to generate a rotating magnetic field to provide a magnetic field signal source. The underground detector (2) comprises two tri-axial fluxgates and three accelerometers. The ground interface box (3) is used for processing the obtained data, and powering the underground detector. The permanent magnet steel drill collar (1) is an obliquely arranged one or a perpendicularly-and-parallelly assembled one. A measuring method for magnetic range measurement is also disclosed.