针对线性调频(linear frequency modulation, LFM)长脉冲信号在时变水声信道中,因频谱畸变导致匹配滤波处理增益损失的问题,提出一种子脉冲匹配滤波相干累积方法。该方法将长脉冲划分为M个子脉冲,然后进行子脉冲匹配滤波,延时对齐子脉...针对线性调频(linear frequency modulation, LFM)长脉冲信号在时变水声信道中,因频谱畸变导致匹配滤波处理增益损失的问题,提出一种子脉冲匹配滤波相干累积方法。该方法将长脉冲划分为M个子脉冲,然后进行子脉冲匹配滤波,延时对齐子脉冲匹配峰值后,精确估计子脉冲匹配峰值间的相位差,并进行相位补偿,最后将补偿对齐后的匹配峰进行相干累积以提高增益。仿真和试验数据处理结果表明,该方法通过子脉冲划分可以克服信道相干极限,且能有效降低因频谱畸变引起的长脉冲匹配滤波处理增益损失,同时保持了长脉冲的大时间带宽积优势,为解决时变信道中LFM长脉冲信号主动探测问题提供了一种新的解决思路。展开更多
Accurate time delay estimation of target echo signals is a critical component of underwater target localization.In active sonar systems,echo signal processing is vulnerable to the effects of reverberation and noise in...Accurate time delay estimation of target echo signals is a critical component of underwater target localization.In active sonar systems,echo signal processing is vulnerable to the effects of reverberation and noise in the maritime environment.This paper proposes a novel method for estimating target time delay using multi-bright spot echoes,assuming the target’s size and depth are known.Aiming to effectively enhance the extraction of geometric features from the target echoes and mitigate the impact of reverberation and noise,the proposed approach employs the fractional order Fourier transform-frequency sliced wavelet transform to extract multi-bright spot echoes.Using the highlighting model theory and the target size information,an observation matrix is constructed to represent multi-angle incident signals and obtain the theoretical scattered echo signals from different angles.Aiming to accurately estimate the target’s time delay,waveform similarity coefficients and mean square error values between the theoretical return signals and received signals are computed across various incident angles and time delays.Simulation results show that,compared to the conventional matched filter,the proposed algorithm reduces the relative error by 65.9%-91.5%at a signal-to noise ratio of-25 dB,and by 66.7%-88.9%at a signal-to-reverberation ratio of−10 dB.This algorithm provides a new approach for the precise localization of submerged targets in shallow water environments.展开更多
文摘针对线性调频(linear frequency modulation, LFM)长脉冲信号在时变水声信道中,因频谱畸变导致匹配滤波处理增益损失的问题,提出一种子脉冲匹配滤波相干累积方法。该方法将长脉冲划分为M个子脉冲,然后进行子脉冲匹配滤波,延时对齐子脉冲匹配峰值后,精确估计子脉冲匹配峰值间的相位差,并进行相位补偿,最后将补偿对齐后的匹配峰进行相干累积以提高增益。仿真和试验数据处理结果表明,该方法通过子脉冲划分可以克服信道相干极限,且能有效降低因频谱畸变引起的长脉冲匹配滤波处理增益损失,同时保持了长脉冲的大时间带宽积优势,为解决时变信道中LFM长脉冲信号主动探测问题提供了一种新的解决思路。
基金Supported by the State Key Laboratory of Acoustics and Marine Information Chinese Academy of Sciences(SKL A202507).
文摘Accurate time delay estimation of target echo signals is a critical component of underwater target localization.In active sonar systems,echo signal processing is vulnerable to the effects of reverberation and noise in the maritime environment.This paper proposes a novel method for estimating target time delay using multi-bright spot echoes,assuming the target’s size and depth are known.Aiming to effectively enhance the extraction of geometric features from the target echoes and mitigate the impact of reverberation and noise,the proposed approach employs the fractional order Fourier transform-frequency sliced wavelet transform to extract multi-bright spot echoes.Using the highlighting model theory and the target size information,an observation matrix is constructed to represent multi-angle incident signals and obtain the theoretical scattered echo signals from different angles.Aiming to accurately estimate the target’s time delay,waveform similarity coefficients and mean square error values between the theoretical return signals and received signals are computed across various incident angles and time delays.Simulation results show that,compared to the conventional matched filter,the proposed algorithm reduces the relative error by 65.9%-91.5%at a signal-to noise ratio of-25 dB,and by 66.7%-88.9%at a signal-to-reverberation ratio of−10 dB.This algorithm provides a new approach for the precise localization of submerged targets in shallow water environments.
