Patent ID: 7159672
Filing Date: 2007-01-09
Classification: E21B,H01Q

Abstract:
1. In a system in which a boring tool is moved through the ground in a region, an apparatus for tracking the position and/or guiding the boring tool as it moves through the ground, said apparatus comprising: a transmitter located within said boring tool for transmitting an electromagnetic field; one or more detectors for receiving said electromagnetic field, each detector having an electromagnetic field receiving antenna assembly including at least one antenna for measuring at least one component of the intensity of said electromagnetic field, with each detector being positioned at a fixed position within said region; and a processor configured for using certain initial conditions, established prior to drilling, in conjunction with at least one measured component of the intensity of said electromagnetic field, which is obtained using said detector or detectors after the boring tool moves a distance along said path, in determining, at least to an approximation, the position of the boring tool after moving said distance.