The Effects of Speed and Platform Stability On Em61 Mk2 Anomaly Responses

The U.S. Army Engineering & Support Center, Huntsville collected and evaluated EM61<br>MK2 electromagnetic data over a controlled test site using five different platforms, each<br>deployed multiple times at different tow speeds. We evaluated the effects of sensor speed on the<br>noise levels and peak anomaly amplitudes of measured EM data and we evaluated the effects of<br>different tow platforms on both background and anomaly responses. We analyzed our data to<br>derive background noise statistics for each dataset, anomaly peak responses corrected for<br>background noise, the spatial extent of anomalies, and anomaly signal to noise ratios.<br>We found that background noise increases as tow-speeds increase. With few exceptions,<br>anomaly peak responses and SNRs decreased as the tow speed was increased. On average, the<br>data show that the spatial extent of anomalies increased as tow speed increased. Our results<br>suggest that improvements to platform stability result in lower background noise levels and<br>increased SNRs. We also found that the background noise and anomaly responses increased<br>when the sensor height above the ground was reduced.