Patent ID: 6396275
Filing Date: 2002-05-28
Classification: E21B,G01V

Abstract:
In an overall system in which a boring tool is moved through the ground within a given region along a particular path while transmitting a locating signal, said boring tool moving in an orientation which includes pitch, said locating signal exhibiting a pair of negative locate points at the surface of the ground, a locating arrangement for determining the depth of said boring tool at a particular position, said locating arrangement comprising:a portable locator including (i) at least two antennas which are arranged orthogonally with respect to one another for use in identifying a negative locate point corresponding to said particular position of the boring tool along said particular path, (ii) an arrangement configured for measuring a signal strength of the locating signal at said negative locate point using said antennas, (iii) a pitch sensing arrangement for determining the pitch of the boring tool while the portable locator is positioned at said negative locate point, and (iv) a processing section configured for using the measured signal strength and the determined pitch to establish the depth of said boring tool beneath the surface of the ground at said particular position.