Patent ID: 6833795
Filing Date: 2004-12-21
Classification: G01V

Abstract:
An underground object detection system for use with a horizontal directional drilling (HDD) machine, comprising:a drill pipe configured to cooperate with the HDD machine to produce a horizontal bore; a transmit apparatus, the transmit apparatus provided with the drill pipe and transmitting electromagnetic probe signals from the drill pipe; a receive apparatus, the receive apparatus provided with the drill pipe and receiving electromagnetic return signals resulting from the probe signals; and a processor coupled to the transmit and receive apparatuses, the processor comparing amplitudes of at least some of the return signals acquired at a time when one or more antennae of the transmit and receive apparatuses are oriented along a substantially horizontal plane relative to a surface of the earth, and generating an alert signal indicative of a detected object in proximity with the drill pipe in response to the processor comparing return signals having about the same amplitude.