Patent ID: 7182151

Claim:
A system for use in horizontal directional drilling, comprising: an above-ground locator, comprising: a transmitter arranged to transmit a locator signal in a substantially vertical direction into a subsurface; a receiver arrangement comprising at least one receive antenna; and a processor; and a beacon assembly configured for sub-surface deployment, comprising: a beacon receiver arrangement comprising an antenna arrangement adapted to detect the locator signal transmitted from the above-ground locator; an orientation sensor adapted to sense an orientation of the beacon assembly; circuitry coupled to the orientation sensor and beacon receiver arrangement, the circuitry configured to produce a beacon signal used to determine a position of the beacon assembly relative to the above-ground locator in response to the locator signal received by the beacon receiver arrangement and the orientation of the beacon assembly; and a beacon transmitter configured to transmit the beacon signal to an above-ground location; whereby the locator receiver arrangement is configured to receive the beacon signal and the locator processor is configured to determine the position of the beacon assembly with respect to the locator using the received beacon signal.