合成孔径激光雷达距离像分辨率非线性恶化与补偿

Nonlinear degradation and compensation on range resolution in synthetic aperture ladar experiment

详细研究了合成孔径激光雷达实验室演示成像实验中因发射激光器非线性调频而带来的距离像分辨率恶化及其补偿。理论分析了因采用线性调波长而非线性调频率光源引起的外差信号频谱展宽及其对距离像分辨率恶化的影响;比较了采用匹配参考信道或不匹配参考信道对距离像恶化的两种补偿办法;数值模拟计算了非线性调频带来的距离像分辨率恶化及其补偿后的图像;建立了以1.55μm可调谐光纤激光器为发射源的演示实验装置,演示了距离像恶化的严重性和补偿的有效性,给出了采用参考信道补偿对距离像分辨率影响的详细数据。

Nonlinear degradation and its compensation on range resolution in synthetic aperture ladar imaging experiment caused by nonlinear frequency modulation in the transmitting laser source are investigated in detail. Theoretical discussion is carried out on the frequency broadening in the heterodyne detection signal and its influence on the degradation of range resolution due to the use of linear wavelength sweeping laser source instead of linear frequency sweeping laser source. Two compensation methods utilizing matched reference channel or mismatched reference channel are compared. Numerical simulations on degraded or corrected range images are given. An experimental demonstration using 1.55 μm tunable fiber laser system is setup and results on degradation and compensation are obtained.