基于对称小波降噪及非对称高斯拟合的激光目标定位

发布时间：2018-11-21 10:03

【摘要】：针对数字体制机载多脉冲激光测距机信号处理算法引入测距误差的问题,提出减少脉冲激光回波波形失真的降噪算法以及改善激光测距精度的校正措施,可用于脉冲激光目标的精确定位。结合数字体制多脉冲激光目标检测过程分析数字信号处理算法引入的测距误差,指出信号采样率限制了目标定位的距离分辨率,低通滤波环节的非线性相频特性是造成波形失真、峰值点偏移的主要因素。然后,针对这些问题给出了改善多脉冲激光目标定位精度的具体算法:基于对称小波基实施回波信号小波分解,利用改进Donoho阈值处理小波系数,用以减小重构目标波形峰值点位置的偏移;采用差分组合函数搜索目标回波的峰值点,基于非对称高斯脉冲模型进行高采样率拟合,对峰值点位置加以校正,改善定位的精确性。通过仿真选取合适的小波基,对比不同算法信噪比改善及峰值点定位的性能。在室外高塔开展消光比激光测距实验,结果显示信噪比为1.5的激光目标定位精度小于2m,验证了多脉冲激光目标精确定位算法的性能。
[Abstract]:Aiming at the problem of introducing ranging error into the signal processing algorithm of digital airborne multi-pulse laser rangefinder, the noise reduction algorithm to reduce the distortion of pulse laser echo waveform and the correction measures to improve the accuracy of laser ranging are put forward. It can be used for accurate location of pulsed laser target. Combining the detection process of multi-pulse laser target with digital system, the ranging error introduced by digital signal processing algorithm is analyzed, and it is pointed out that the sampling rate of signal limits the range resolution of target location. The nonlinear phase frequency characteristic of low pass filter is the main factor of waveform distortion and peak deviation. Then, to solve these problems, a specific algorithm to improve the accuracy of multi-pulse laser target localization is presented: wavelet decomposition of echo signal based on symmetric wavelet basis, wavelet coefficients processing using improved Donoho threshold, In order to reduce the shift of peak point position of reconstructed target waveform; The difference combination function is used to search the peak point of the target echo, and the high sampling rate fitting based on the asymmetric Gao Si pulse model is carried out to correct the peak position and improve the accuracy of the location. The performance of different algorithms in improving SNR and peak-point location is compared by selecting suitable wavelet bases. The experiment of laser ranging with extinction ratio in outdoor tower shows that the accuracy of laser target location with SNR 1.5 is less than 2 m, which verifies the performance of multi-pulse laser target location algorithm.
【作者单位】：北京工业大学信息学部;郑州航空工业管理学院电子通信工程系;中航工业集团公司洛阳电光设备研究所;
【基金】：国家自然科学基金重点项目(61331021) 航空科学基金重点项目(2014ZC13004) 河南省高校科技创新团队支持计划(17IRTSTHN014)
【分类号】：TN958.98

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