【作者】 冯宇；

【导师】 胡飞；

【作者基本信息】 华中科技大学 ， 通信与信息系统， 2009， 硕士

【摘要】 被动毫米波(Passive Millimeter-wave, PMMW)成像技术具有全天时、全天候的工作能力,并且因为不发射电磁波,具有很高的隐蔽性和抗干扰性,对人体很安全,在军用和民用的许多领域都具有广阔的应用前景,但是早期采用单波束结合机械扫描成像的体制使得它的成像实时性和灵敏度相对较低。近年来,PMMW多波束阵列成像技术发展很快,一定程度上解决了上述问题,其中又分为基于相干探测方法和非相干探测方法的两个主要发展方向。论文首先全面介绍了PMMW成像的国内外发展现状,然后详细阐述了作为实孔径成像理论基础的毫米波辐射计成像原理。在此基础上重点分析了PMMW焦平面成像的空间采样频率要求以及多波束天线原理,再对毫米波干涉测量进行分析,推导出复相关输出与场景亮温分布的关系式。最后通过对PMMW焦平面阵列中相邻馈源波束存在的重叠区域,采用相关的方法加以利用获得新的像素信息,提出了一种融合干涉测量的焦平面成像方法。该方法将相干和非相干技术进行有效融合,能增加PMMW多波束成像像素,提高成像分辨率。对提出的方法进行了具体的理论分析,并通过仿真实验进行了验证。更多还原

【Abstract】 Passive Millimeter-wave(PMMW) imaging can work in all kinds of weather conditions in whole day. Without any active emission of Hertzian signal from the system, PMMW imaging has strong abilities of concealment and anti-jamming, as well as it is harmless to human body, so it is hoped to be widely used in both civil applications and military applications. In the beginning, by mechanically scanning with single beam, PMMW imaging had low sensitivity and must take a long time to generate a image. Since recent years, multi-beam array imaging has been developed quickly, which solves the problems above in a certain extent, and according to coherent and incoherent measurements, it has two major branches.Firstly, we represent the state-of-the-art of PMMW imaging technology, then explain the principles of millimeter-wave radiometer imaging which is the basis of real aperture imaging theories. After that, we focus on analyzing the spatial sampling frequency and multi-beam theory of PMMW focal plane imaging. Then we analyse the principles of millimeter-wave interferometry, and explore the relationship between complex correlation output and brightness temperature of the scene. In the end, by introducing interferometric measurements for the overlap between the beams of adjacent feeds in PMMW focal plane array , a method is proposed to generate more image pixels than the conventional focal plane imaging methods ever did. Combining coherent technology with incoherent technology, the method can increase the number of image pixels, and therefore improve the spatial resolution of PMMW multi-beam imaging. Theoretical analysis and simulation results both demonstrate the effectiveness of the method.更多还原