基于时频分析的合成孔径激光雷达成像算法

建立了SAL回波信号模型,推导计算了微振动对SAL回波相位的影响。分别采用RD算法和基于SPWVD分布的时频成像算法对工作于机载正侧视条带模式的SAL系统进行数值仿真分析。结果表明,在SAL平台作平稳飞行时,采用RD算法可以清晰地对点目标进行成像;根据实际情况引入振动频率不超过500 Hz、振幅不超过0.2 mm的微振动参数,采用RD算法所得到图像的方位分辨率严重下降,采用基于SPWVD分布的时频成像算法可以有效消除振动引起的多普勒频移及其对成像的影响。

Synthetic Aperture Ladar Imaging Based on Time-Frequency Analysis

The signal model of synthetic aperture ladar is set up, and the influence of micro vibration error on the phase of echo signal of the SAL is computed. Numerical simulation on a SAL system in strip - mode used in RDA and imaging algorithm based on SPWVD time-frequency analysis are carried out. The simulation results show that in the condition of steady flying, the ideal point target can be imaged clearly with RDA. On the reference of the national military standard for environment, in the condition of the frequency below 500MHz and the amplitude below 0.2mm, the azimuth resolution of image used in RDA is badly debased. Doppler frequency motion from vibration and its influence on imaging resolution can be effectively eliminated used in the imaging algorithm based on SPWVD time- frequency analysis.