The fault detection of transmitting current encoded by m-sequence using triple-correlation function in helicopter-borne electromagnetic method

Abstract

An m-sequence is applied to the helicopter-borne electromagnetic method system for the first time, and there are many problems to be solved, one of which is the detection of the quality of the transmitting current waveform, which directly affects the resource survey results. In this research, we found that the triple-correlation function (TCF) can reveal the bit integrity characteristics of the m-sequence encoded transmitting current. On this basis, this paper proposes to extract the three-dimensional information of the normalized TCF plot by using a peak detection method and, then, proposes to use a dual-threshold method to clarify the detection results. The whole process realizes the fault detection of the transmitting current waveform. We propose a reasonable transmitting current modeling method and conduct 1200 random experiments in 12 groups. The statistics of the experimental results show that when the number of missing bits is 1, 2, 4, and 8, the fault detection accuracy can reach more than 83%. A comparative experiment using the Field Programmable Gate Array. in the laboratory validates the feasibility of the fault detection method. This method is beneficial to improve the quality of detection data and avoid economic losses caused by invalid detection flights.