A study on time-domain AEM testing and calibration method based on anomaly loop

To verify the measurement accuracy and effectiveness of airborne time domain electromagnetic system(AEM), this paper provides a method to simulate the underground finite conductor using closed anomaly loop placed on the ground. System error and flight geometric parameter error can be determined by the fitting analysis of the theoretical electromagnetic response value and the measured data. On the basis of closed anomaly loop electromagnetic response calculation, we study the relationship among decay curve, profile curve, the loop electrical properties and the geometric parameters, and design a field experimental plan. To test this plan, we do field experiment utilizing a crane near the DaEDao in Changchun, the final results show that the average absolute error of the single measured data is 0. 48 mV, the system relative error is less than 1%, the flight altitude error is 0.4 m, and the horizontal offset error is 0. 2 m. It is an accurate, fast, economical and feasible method to test and calibrate the AEM system by using closed anomaly loop placed on the ground. This simulation method has some advantages, such as convenient field construction and flexible parameter adjustment, and the proposed method is suitable for testing many kinds of AEM system.