Patent ID: 6459266
Filing Date: 2002-10-01
Classification: E21B,G01V

Abstract:
A method for detecting the relationship between a locator and an inaccessible object, said inaccessible object having means for generating a magnetic field and said locator having detecting means for detecting the generated magnetic field and a magnetic compass, the method comprising:(a) measuring horizontal and vertical components of said generated magnetic field using the locator in a first position; (b) processing said measurements to determine the separation of said inaccessible object from said locator in the first position; (c) moving said locator to a second position and using said compass to ensure that said locator has the same orientation relative to the Earth's magnetic field as in said first position; (d) measuring horizontal and vertical components of said generated magnetic field using the locator in the second position; and, (e) processing said measurements to determine the separation of said inaccessible object from said locator at the second position.