基于光纤链路传输的远程超宽带混沌成像雷达

Ultra-Wideband Remote Chaotic Imaging Radar over Fiber Links

提出了一种基于光纤链路传输的远程超宽带混沌成像雷达系统。该系统包括中心站、光纤传输链路和基站。在中心站,改进型Colpitts振荡器产生超宽带混沌信号,经上变频后作为雷达探测信号。探测信号通过激光器的外调制技术转换为相应的光信号,经光纤链路传输到基站并转换为相应电信号,由宽带天线发射。目标物反射的回波信号经电光转换和下变频在中心站被采集。利用相关运算和后向投影算法,中心站可实现对目标物的二维空间成像。实验结果表明,该系统经过10 km光纤传输后可对单个和多个目标物进行远程成像。成像的距离分辨率和方位分辨率分别为6 cm和8 cm。

A remote imaging radar system based on ultra-wideband chaotic signal generation and radio over fiber is proposed and demonstrated experimentally. The radar system consists of a central station, optical fiber links and a base station. At the central station, an ultra-wideband chaotic signal is generated by an improved Colpitts oscillator and then is up-converted as a probe signal. The probe signal is converted into an optical signal by using the external modulation technique of laser diode. Optical fiber links are used to transport optical signals to the remote base station or back to the central station. At the base station, the optical signal is transformed into the microwave signal and then transmitted by a horn antenna. At the receiving end, the echo signal from a target is converted to be in optical domain and then transported to the central station, where it is collected after optical-to-electrical conversion and down conversion. The target imaging is obtained by utilizing the correlation method and back projection algorithm. Experimental results show that the proposed radar system can achieve remote imaging for single and multiple free-space targets with a distance of 10 km. The range resolution of 6 cm and the azimuth resolution of 8 cm are obtained, respectively.