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The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified particle filtering (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the particle filtering (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the particle sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the "likehood" function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. [ABSTRACT FROM AUTHOR]

There are plenty of weak audio analog signals in ocean, whose signal characteristic is usually an important basis for the target detection in ocean, therefore it is necessary to seek for approaches to detect the weak audio signal. Stochastic resonance, which is regarded as a novel method for detecting the weak signal, has been applied in many areas. However, the most researches concentrate on the single-frequency weak signal, and less research on the multi-frequency weak signal. Starting from the basic bistable stochastic resonance system, theoretical analysis on the multi-frequency analog signal with strong noise is carried out, and a method for detecting and recovering the multi-frequency analog signal is proposed, which is based on the average inversion and interpolation fitting. The analysis and simulation results present that, the multi-frequency analog signal is successfully detected and recovered in the condition that the input signal-to-noise ratio (SNR) is -22dB.Compared with the traditional filter method, the proposed method can effectively reduce the waveform distortion and phase delay of the multi-frequency signal, and it is especially suitable for the detection of multi-frequency weak signals whose frequencies are very close, which makes it possess good theoretical guidance and practical application value. [ABSTRACT FROM AUTHOR]