Low frequency electromagnetic signals play an important role in the detection of underground electrical structure. After propagation of long distance, signal will be attenuated to a certain extent and probably buried in noise, make it difficult to ext...
Low frequency electromagnetic signals play an important role in the detection of underground electrical structure. After propagation of long distance, signal will be attenuated to a certain extent and probably buried in noise, make it difficult to extract. In this paper, the method of multi-layer autocorrelation will be used to detect and extract the weak low frequency electromagnetic signal, and its performance will be compared with the narrow-band filter and the method of synchronous accumulation. Simulation results show that the correlation coefficient of signal obtained by multi-layer autocorrelation and source signal can achieve more than 0.8 when SNR is -18dB. However, the value of narrow-band filter and synchronous accumulation is lower than that mentioned above when SNR is only -14dB. Experimental verifies that multi-layer autocorrelation method can suppress noise more effectively and detect weak signals more accurately.