Abstract: An apparatus and method of determining the position of a drilling tool during drilling is provided. The apparatus includes a magnetic source mounted to a rotating drilling tool and at least two magnetometers, which are located outside a drilled hole. Sensing data of a rotating magnetic field is transmitted from the magnetometers to a control unit provided with a position calculation algorithm. The control unit is also provided with position data of the magnetometers and a reference position of the drilling tool. The control unit compares the received sensing data when the drilling tool is in the reference position and when being moved to a new position. Phase angles are then detected from the sensing data. The algorithm utilizes the phase angles and the known positions of the magnetometers and the reference point when calculating the changed position.

Abstract: An apparatus and method of determining position of a drilling tool during drilling is disclosed. The apparatus includes a magnetic source mounted to a rotating drilling tool and at least three magnetometers, which are located outside a drilled hole. Sensing data of the rotating magnetic field is transmitted from the magnetometers to a control unit (CU) provided with a position calculation algorithm. The control unit is also provided with pose data of the magnetometers. The control unit compares the received sensing data and determines phase angles from the sensing data. The algorithm utilizes the phase angles and the known positions of the magnetometers when calculating the position.