Patent ID: 7150331

Claim:
A tracking system for use in horizontal directional drilling, comprising: an above ground tracker assembly comprising: a dipole field transmitter oriented in a substantially vertical plane; a tracker receiver arrangement comprising at least one receiving antenna; and a tracker processor; and a beacon assembly comprising: a beacon receiver arrangement comprising a plurality of receiving antennas orthogonally arranged and adapted to detect the dipole field transmitted from the tracker; an orientation sensor adapted to sense an orientation of the beacon assembly; a beacon processor adapted to determine the position of the tracker assembly with respect to the beacon assembly in response to the field detected by the beacon receiver arrangement and the orientation of the beacon assembly; and a beacon transmitter adapted to transmit a dipole field containing information related to the position of the tracker assembly; and wherein the tracker receiver arrangement is adapted to detect the dipole field transmitted from the beacon transmitter; and wherein the tracker processor is adapted to determine the position of the beacon assembly with respect to the tracker assembly in response to the information contained in the dipole field detected by the tracker receiver arrangement.