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针对纳秒量级脉宽机载多脉冲激光照射目标的回波波形,提出几何分割比这一目标姿态不敏感特征,给出了特征提取算法,可用于与激光目标运动状态结合开展目标检测与跟踪。首先,基于激光目标波形数学模型分析目标波形与目标特征的关系,指出激光目标的几何分割比特征具备姿态不敏感特性。接着,结合目标特征提取对目标波形和噪声不失真分离的要求,提出在小波域利用对称小波基进行改进Donoho阈值降噪处理,在时域利用小波重构信号阈值获取目标波形序列,再由一阶二阶差分计算检测目标波形峰值点,进而提取激光目标散射中心及几何分割比等特征。最后,通过仿真实验验证算法在低信噪比下提取激光目标特征信息的有效性。在与机载多脉冲激光目标模拟器联试实验中,利用文中算法提取激光目标特征结合目标的运动状态信息,开展多帧相关匹配检测,多脉冲激光目标检测的可靠性明显提高。
Aiming at the echo waveform of target irradiated by nanosecond pulse width on-board multi-pulse laser, the feature of geometrical partition ratio is proposed, and the feature extraction algorithm is proposed. It can be used in target detection and motion detection combined with laser target motion track. First, the relationship between the target waveform and the target feature is analyzed based on the laser target waveform mathematical model. It is pointed out that the geometric segmentation ratio features of the laser target possess the attitude insensitivity characteristics. Then, combined with the target feature extraction, the target waveform and the requirement of noise isolation are proposed. In the wavelet domain, the improved Donoho threshold denoising process is proposed using symmetric wavelet bases, the target waveform sequence is obtained using wavelet reconstruction signal threshold in the time domain, The second-order difference calculation detects the peak of the target waveform, and then extracts the characteristics such as the scattering center of the laser target and the geometric segmentation ratio. Finally, the validity of the laser target feature information extraction algorithm at low signal-to-noise ratio is verified by simulation experiments. In experiments with the airborne multi-pulse laser target simulator, the laser target features are extracted and combined with the motion state information of the target to carry out multi-frame correlation matching detection. The reliability of multi-pulse laser target detection is obviously improved.