Abstract:

Nuclear quadrupole resonance (NQR) is a solid state radio frequency spectroscopic technique, allowing the detection of many high explosives. Unfortunately, NQR signals are inherently weak and vulnerable both to the thermal noise of the coil and any radio frequency interference, and the precise estimation of the NQR  signal  parameters becomes a difficult problem. A residual signal iterative analysis algorithm based on improved fast maximum likelihood estimation is proposed to estimate the parameters of the NQR signal. The proposed method turns the multidimensional search problem into multiple one dimensional searches to effectively solve the mask problem of the interference to the NQR signal, which simultaneously reduces the computational complexity and improves the estimated precision. The effectiveness of the proposed algorithm is demonstrated by the processing results of both simulated data and experimental data.