Combined wave emission system based on dual resonance method for airborne transient electromagnetic detection

To improve the detection efficiency of airborne transient electromagnetic method (ATEM) and reduce the times of flight experiments, a dual resonance-based combined wave emission circuit is proposed in this paper, which realizes the combined emission of half-sine wave and triangular wave through the selection of different resonant branches. Based on the operating principle of the proposed emission circuit, the model of second-order resistor-inductor-capacitor equivalent circuit is established. Then, the generation process of the combined wave is analyzed, and the segmentation control method is proposed. Finally, the feasibility and effectiveness of the proposed combined wave emission system are verified by simulation model building and prototype testing, and the results show that the emission current has good quality and high stability. Compared with the traditional emission of single wave current, the combined wave current has the advantages of large magnetic moment of half-sine wave and rich high-frequency components of triangular narrow pulse, which can effectively expand the detection range and improve the measurement efficiency of ATEM.