EM System With Dramatic Multi-Axis Transmitter and Tensor Gradiometer Receiver

摘要

The objective of the work was to demonstrate that sensor pairs could be used to adequately approximate the spatial gradients of the vector dB/dt field and to test if the use of sensor differences improved or degraded the quality of data compared to conventional measurements. An array of four, small, three-component sensors was shown to be useful to approximate the spatial gradient tensor when the target was not exceedingly c lose to the sensors. Computations using the gradient tensor are simpler and faster than conventional computations and offer opportunities for improved target resolution and separation of multiple overlapping signatures. Efficient computations were implemented and tested. Subtracting signals from pairs of sensors decreases signal and also decreases noise, so signal to noise ratio can be better. Measurements showed that differences signals improved signal to noise ratio in situations that are typically encountered in target detection surveys but neither improved nor degraded SNR in situations typically encountered in cued identification and characterization surveys.