Patent ID: 8614576
Filing Date: 2013-12-24
Classification: G01V

Abstract:
1. A method for detecting a target in a soil, the method including the steps of: generating a transmit signal, the transmit signal includes a repeating sequence, each sequence includes a first period and a second period, the first period preceding the second period; transmitting a transmit magnetic field by applying the transmit signal to a transmit coil; sensing a current through the transmit coil during at least a part of the second period of at least a first sequence to produce a first control signal; controlling at least a part of the transmit signal during at least one of: a part of the second period of the first sequence and a part of the second period of one or more subsequent sequences using the first control signal such that the reactive transmit voltage across the transmit coil during subsequent second periods of the transmit signal is maintained approximately constantly zero with a corresponding current through the transmit coil being non-zero; receiving a receive magnetic field using a receive coil to produce a receive signal; processing the receive signal during at least a part of the second period; and producing an indicative output signal indicating the presence of the target based on the processing of the receive signal.