Differential Target Antenna Coupling (DTAC) EM Surveying with Stationary Transmitter Loop and Moving In-Loop Receivers

Following our previous studies of the Differential Target Antenna Coupling (DTAC) method with horizontal and vertical arrays for EM surveys, in this paper we study the application of the DTAC method to a different configuration, where a large, stationary transmitter loop is on the ground surface. We then run profile lines inside this loop. The DTAC method is effective in eliminating errors due to the large variations in the primary field along profile lines within the transmitting loop. Operational tests show that we obtain more diagnostic DTAC anomalies over buried targets than using just the Bx and By data. The DTAC method also produces smaller false-alarm targets due to background geology variations, compared with Bz measurements. The DTAC method can be used with either time- or frequency-domain data and the receiver can be moved on the ground or deployed from an airborne vehicle, such as a drone.