基于圆锥扫描的W波段毫米波辐射成像系统

A MMW Radiometric Imaging System Based on Conical Scanning at W Band

为了提高机械扫描体制毫米波辐射成像系统的视域,研制了一种基于圆锥扫描的W波段毫米波辐射成像系统.中心频率为94.5GHz的毫米波全功率直接检波式辐射计被搭载于二维圆锥扫描平台上,扫描平台受计算机配套软件控制,由伺服电机驱动对球坐标系的方位角和俯仰角进行空间采样,使辐射计天线波束遍历成像视域,辐射计输出的电压信号由数据采集卡传回计算机软件进行辐射图像重构.配套软件可以设置扫描范围、扫描间隔、扫描速度等参数,并支持查看原始图像、保存原始数据等功能.方位角的最大扫描范围为-160°～+160°,俯仰角的最大扫描范围为-75°～+75°.通过建筑物成像实验验证了本文系统的大视域成像能力,指出圆锥扫描的成像方式会带来视觉上的、可校正的非线性畸变.

A Millimeter wave（MMW）radiometric imaging system based on conical scan at W band was developed to enlarge imaging scene for mechanical scanned passive MMW imaging system.A total power direct detection radiometer with center frequency of 94.5 GHz is carried on a two dimensional（2 D）conically scanned platform.The platform is controlled by supporting software on computer and driven by servo motors,and processes space sample in azimuth and elevation dimensions of spherical coordinate.The radiometer antenna beam is traversed into the imaging field of view.Radiometer output voltages are recorded and sent back to supporting software for radiometric image reconstruction.The software supports scanning range,step,and speed configuration,raw image view and original data storage function.The maximum scanning range for azimuth is from-160°to 160°,while that for elevation is from-75°to 75°.Finally,an imaging experiment towards a building demonstrates that the proposed system is able to image a large scene,and indicates that conical scan approach leads to visual but correctable nonlinear distortion.