Patent ID: 7061244

Claim:
In a system for moving a boring tool within an underground region in which the boring tool is configured for transmitting a dipole locating signal while moving along an intended path such that fore and aft locate points are defined ahead of and rearward from the boring tool at the surface of the ground, each of said fore and aft locate points having a flux orientation which is normal to the surface of the ground, said system including a locator for receiving the locating signal, a method comprising: using said locator to identify at least one of the fore and aft locate points; measuring a locate point signal strength of the locating signal at the identified locate point using said locator; and storing a reference value, based on the locate point signal strength, such that any measured signal strength of the locating signal corresponding to a given above ground point is identifiable as being greater than the locate point signal strength and establishes that the given point is between said fore and aft locate points.