一种新的高重频宽带相干激光雷达系统研究

A Novel Coherent Ladar System with High Repetition Frequency and Wide Bandwidth

该文提出一种新的同时具有高重复频率和大带宽性能的相干激光雷达系统。该系统基于I&Q调制器正交调制技术与带宽合成信号处理技术,使得系统能够同时满足大带宽和高重复频率的要求,解决了传统激光雷达宽带信号调制速度慢的问题。该系统能够生成高重频、大带宽的相干线性调频激光雷达信号,在高分辨距离成像、(逆)合成孔径激光雷达成像、距离分辨的振动测量等方面,具有重要的应用价值。文中阐述了宽带高重复频率调制的原理和方法、基于微波域频率步进的带宽合成信号处理方法,并进行光纤环路实验和自由空间实验。作为演示,该激光雷达系统获得了16.7 k Hz重复频率、6 GHz带宽,实现了优于2.5 cm距离向分辨率成像及远距离运动目标逆合成孔径激光雷达成像。实验结果证明了该系统与方法的有效性。

A novel coherent ladar system with high repetition and wide bandwidth is proposed. Based on the IQ modulator from the fiber communication community and the bandwidth synthesis technique, the proposed system provides wide bandwidth with high repetition rate, which is difficult for conversional ladar system based on tuning the wavelength of a tunable laser. The proposed system is expected to be useful for high range resolution imaging, Inverse Synthetic Aperture Ladar（ISAL）, range resolved vibration measurement. The operation principle, system description, and signal processing method for bandwidth synthesis are discussed in the paper. And experiments are performed both in fiber delay line and free space. As a demonstration, the system generates signal with 6 GHz at repetition rate of 16.7 k Hz. The resolution of the obtained images is finer than 2.5 cm. The experimental results demonstrates the effectiveness of the proposed system and the processing method.