叶簇穿透雷达系统设计综述(英文)

A Summary of Foliage Penetration Radar System Design

叶簇穿透(FOPEN)雷达是一种用于发现和表征密集叶簇下人为目标及表征叶簇自身的技术手段。这种雷达已经在军事监视和民用地理空间成像方面得到应用。本次讲座分为三大部分:第一部分讲述FOPEN雷达的早期历史,主要讲述战场监视及叶簇穿透雷达的早期试验。其中,某些雷达技术的发展意义重大,支撑探测密集叶簇下面固定和移动目标的能力。这些技术中最重要的部分就是众所周知的相干雷达与数字处理技术。同样重要的是雷达穿透叶簇的量化及其散射损耗影响。第二部分重点讨论了几种军民用FOPEN合成孔径雷达系统及其研究成果。在对每种雷达系统概述过程中还通过举例说明SAR图像及其固定目标探测能力。这一部分还给出了量化极化分集在探测和表征人为和自然目标时的好处。在目标描述与降低虚警方面,极化技术的优势明显。最后讨论了超宽带和超宽角成像技术。第三部分讨论的是多模超宽带雷达最新研究及SAR和动目标显示(MTI)FOPEN系统的设计。重点是设计这些超宽带(UWB)系统的优势和困难,以及实际电磁环境下的工作情况。讲座最后两部分阐述了文献中出现的一些用于未来多模式工作的新技术:探测可辨别低速运动目标的需求;双基地SAR与固定GMTI照射波形的协同工作。

Foliage penetration（FOPEN） Radar is a technical approach to find and characterize man-made objections under dense foliage,as well as characterizing the foliage itself.It has applications in both military surveillance and civilian geospatial imaging.This tutorial is divided into three parts.Firstly,the early history of FOPEN Radar：battlefield surveillance and the early experiments in foliage penetration radar are covered.There were some very interesting developments in radar technology that enabled our ability to detect fixed and moving objects under dense foliage.The most important part of that technology was the widespread awareness of the benefits of coherent radar and the advent of digital processing.Almost as important was the quantification of the radar propagation through foliage,and its scattering and loss effects.Secondly,FOPEN synthetic aperture radar（SAR）：with concentration on development results from several systems.These systems were developed for both military and commercial applications,and during a time of rapid awareness of the need and ability to operate in a dense signal environment.A brief description of each radar system will be provided along with illustrations of the SAR image and fixed object detection capability.The next section will quantify the benefits of polarization diversity in detecting and characterizing both man made and natural objects.There is a clear benefit for use of polarization in the target characterization and false alarm mitigation.Finally the techniques developed for ultra wideband and ultra wide angle image formation will be presented.In the end,new research in multi-mode ultra-wideband radar：with the design of both SAR and moving target indication（MTI） FOPEN systems.Particular note will be taken on the benefits and difficulties in designing these ultra-wideband（UWB） systems,and operation in real world electromagnetic environments.At common FOPEN frequencies,the systems have generally been either SAR or MTI due to the difficulties of obtaining either bandwidth or aperture characteristics for efficient operation.The last two sections of the tutorial will illustrate new technologies that are appearing in the literature that have promise for future multimode operation：the need to detect low minimum discernable velocity movement;and the operation of bistatic SAR in concert with a stationary GMTI illumination waveform.