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摘要: 星源照射双/多基地合成孔径雷达(SAR),采用卫星发射,卫星、临近空间、飞机、地面等平台接收,实现对地海面场景和目标的高分辨成像。该技术具有可成像范围广、隐蔽性好、抗干扰能力强等优点,且可以通过波束调控实现扫描、聚束、滑动聚束等多种组合成像模式,从而获取更加丰富的成像信息,具有十分广阔的民用和军事应用前景。目前,国内外针对星源照射双/多基地SAR成像技术开展了多年的研究,积累了诸多研究成果。该文分别从系统组成、构型方法、回波模型、成像方法、收发同步与试验验证等方面对该技术进行阐述与分析,同时对相关的研究工作进行较系统的回顾,并展望了星源照射双/多基地SAR成像技术未来的发展方向。Abstract: Bi/multistatic Synthetic Aperture Radar (SAR) using spaceborne illuminator utilizes spaceborne platforms as transmitters and satellites, near-space vehicles, aircraft, and ground platforms as receivers, which allows high-resolution imaging of ground and marine scenes and targets. The system’s benefits include a broad imaging field of view, high concealment, and potent antijamming abilities. By using beam steering methods, a variety of imaging modes can be achieved, such as staring spotlight and sliding spotlight modes, which obtain abundant information about the imaging scene and offer broad application prospects both in civil and military fields. Thus far, the bi/multistatic SAR using spaceborne illuminator has been intensively investigated, and several research findings have been reported. This paper examines the technology from the aspects of system components, configuration design, echo model, imaging techniques, bistatic synchronization, and experimental verification and systematically reviews the state-of-the-art research progress. Finally, it is anticipated that spaceborne illuminator technology will be used to develop bi/multistatic SAR in the future.
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表 1 GEO星机双基SAR系统仿真参数
Table 1. The simulation parameters of geosynchronous spaceborne/airborne bistatic SAR
系统参数 数值 平台参数 数值 载频 1.25 GHz GEO轨道离心率 0.07 带宽 100 MHz GEO轨道倾角 53° 峰值功率 5 kW GEO半长轴长度 42164.17 km 发射天线增益 50 dB 接收站速度 200 m/s 接收天线增益 20.8 dB 接收站高度 10 km 表 2 星源照射双/多基SAR典型系统/试验介绍
Table 2. Typical system introduction of bi/multi-static SAR system with spaceborne illuminators
类别 平台组合 典型系统/试验 国家 研制状态 优劣势与应用价值 发射 接收 同构 SAR卫星 SAR卫星 陆探1号 中国 在轨运行 可实现高精度干涉测量,
用于地表DEM生成与运动目标检测等TerraSAR-X/TanDEM-X 德国 在轨运行 TanDEM-L 德国 正在研制 异构 SAR卫星
GNSS卫
星等飞机、地
面等挑战者号+CV990飞机 美国 验证了星机双基SAR成像可行性 机载接收站:观测视角丰富、响应速度快
地面接收站:感兴趣区域
长时间观测
GNSS卫星:全球覆盖,
带宽与功率受限
SAR卫星:大带宽、
功率密度较高ERS-2/ENVISAT+地面固定站(SABRINA系统) 西班牙 星地双基干涉SAR试验 TerraSAR-X+飞机
(F-SAR/PAMIR)中国、德国、美国 星机SAR成像试验 遥感-1+地面固定站 中国 对比单双基成像结果 TerraSAR-X +地面固定站 中国 DBF提升信噪比 高分-3+飞机 中国 星机双基SAR成像试验 GLONASS/GPS/Galileo +地面固定接收 中国、英国 GNSS星地双基SAR成像试验 GLONASS+飞机 英国、中国 GNSS星机双基SAR成像试验 北斗-2+地面固定接收 中国 GNSS星地双基SAR成像试验 -
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