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Reverberation is the toughest problem faced by active detecting devices working in shallow water, and has limited the performance of active sonar systems to a large extent especially for intermediate and short-range detection or high-power transmition. Based on the precise bearing method using split-beams in passive sonar, this paper presents a binning method for continuous waves to distinguish target...
To detect underwater moving targets effectively in the active sonar systems, the linear frequency modulation signal (LFM) is commonly used as a broadband signal for achieving more processing gain. However, the conventional method that uses the matched filter for detecting the LFM signal cannot remove these undesirable signals easily since its reverberation spectrum structure has a certain similarity...
In the complex variable shallow water acoustic channel, the regular signal emitted by the active sonar would propagate through multiple paths and scattered by the target. Compared with the transmitted signal, the echo signal has a time delay and Doppler spread. This leads to a great decrease of the correlation between the copy vector of the matched filter and the target echo, which degrades target...
Ocean ambient noise is usually considered as an interfering background for underwater devices. As a key component of ocean ambient noise, marine biological noise also has a serious effect on sonar detection performance. It is found that marine mammal noise has a wide frequency band, with the energy mainly concentrating on low frequency band 10 ∼ 500 Hz and medium frequency band 500 Hz ∼ 25 kHz, which...
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