Abstract: In the time domain airborne electromagnetic system, using high-frequency pseudo-random binary sequence as excitation source is an effective way to realize shallow high-resolution geological exploration. In order to improve the identification accuracy, a high-precision identification method based on time-domain cyclic correlation calculation is proposed in this paper. The impulse response of the Earth is obtained by eliminating the side lobe effect and solving the Wiener-Hoff equation in the time domain. The numerical simulation results show that the root mean square value of the relative error in identifying the Earth response is 2.2×10^-7,while the identification error of the Early earth response is less than 10^-10, which proves that this identification method is accurate. Further analysis shows that this high-precision identification method has strong noise suppression ability in a short observation time. The signal-to-noise ratio improved by the single-period identification method is 8.7 dB, which is better than the 6.1 dB improved by the linear superposition noise reduction method under the same conditions.

Key words: airborne electromagnetic, pseudo-random binary sequence, m-sequence, correlation calculation, accurate identification, noise suppression