在Park模型基础上,建立了二维机载正侧视条带模式合成孔径激光雷达(SAL)平台振动对成像的影响简化数学模型;在振动频率不超过500 Hz的情况下,仿真计算了振幅、频率、初相位和峰值加速度等振动参数对SAL图像分辨率的影响,给出了振动影响下理想点目标和扩展面目标的SAL图像。仿真结果表明,振动的峰值加速度是直接和图像模糊程度最相关的量,峰值加速度越大,图像模糊程度越高,存在峰值加速度阈值,小于这个阈值时,图像基本不受影响,而大于另一个阈值时,图像开始出现重影;另外,仿真计算结果也表明,振动初相位对图像质量恶化也有重要影响。

A simple mathematical model is set up to investigate the effect of platform vibration on the image quality in an airborne strip-mode synthetic aperture ladar (SAL) based on the work of Park. Numerical simulation is carried out to show the influence of the vibration parameters such as amplitude,frequency,initial phase,or peak acceleration,on the SAL image resolution within the frequency range of 0-500 Hz. SAL image of ideal point target or extended surface target with or without vibration is given. The simulation results show that the quality of SAL image is most correlated to the peak acceleration of the platform vibration. With higher acceleration,the SAL image deteriorates severely. As illustrated in the simulation,the SAL image is acceptable as the peak acceleration is no more than threshold and will be totally distorted in the azimuth with many ghosts as the acceleration is greater than another threshold. In addition,the simulation results also indicate that initial phase of the vibration plays an important role in deterioration of the SAL image induced by the vibration.