Long-Range Magnetic Tracking System

This paper presents a new long-range full 3-D magnetic tracking system for horizontal directional drilling, and describes its performance. The system is able to determine the full 3-D mutual position of the receiver with respect to the transmitter. The system presented here belongs to the category of hybrid trackers using an active magnetic ranger, an optical gyro, and three micromachined inclinometers. The gyro is used for dead-reckoning navigation over long distances (up to 2 km), and the magnetic tracking system, consisting of a coil magnetic transmitter and a magnetometer receiver, is used when two drill heads are approaching each other beneath the surface at the assumed meeting point. The functionality of the system was verified for the maximum range of 17 m with 1,2-m rms accuracy, and with 0,34-m rms accuracy for the range below 10 m.