Patent ID: 8188746

Claim:
In a system in which a boring tool is moved through the ground by a drill string in a region which includes at least one electrically conductive in-ground line, an apparatus for monitoring a specific positional relationship between the boring tool and said line, said apparatus comprising: a first transmitter for generating a magnetic locating field from one of either said boring tool or at least an underground length of said line; a receiver carried by said boring tool if said field is generated from said line, or connected to said line if said field is generated from said boring tool, for detecting an intensity of said magnetic locating field indicative of the positional relationship between the boring tool and said line; a second transmitter carried by said boring tool for producing a locating signal; and a portable locator for using said locating signal to determine a position of said boring tool within said region and for indicating the detected intensity of said magnetic locating field generated from either one of said line or said boring tool.