逆合成孔径成像激光雷达能够实现对运动目标的高分辨实时成像,但激光信号的极大带宽和目标回波信号的微弱性给雷达回波数据的接收和处理带来了较大困难.针对这一问题,提出了基于光外差探测手段和压缩感知理论相结合的信号采样方法,首先通过光外差探测降低回波信号的有效带宽,再结合压缩感知理论实现对信号的稀疏化采样和重构.仿真结果证明了运用本文所提出的采样方法,在使用远低于奈奎斯特定理所规定的采样率时,仍然能够实现对目标的高质量成像.

Inverse Synthetic Aperture Imaging LADAR can realize the instantaneous high-resolution imaging for moving target. Howerver, the ultra-wide bandwidth of the laser signal and the weakness of the echo signal brings some difficulties in the signal sampling. A method which combines the optical heterodyne detection technique and compressed sensing theory is proposed to solve this problem. The optical heterodyne detection technique is utilized to reduce the bandwidth of echo signal, then the compressed sensing theory is developed to realize sampling and reconstruction of the signal. Simulations demonstrate that high-quality images can be reconstructed even though the sampling rate is much lower than the Nyquist rate.