【作者】 岳海霞；

【导师】 杨汝良；

【作者基本信息】 中国科学院研究生院（电子学研究所） ， 通信与信息系统， 2005， 博士

【摘要】 回波信号模拟是合成孔径雷达模拟技术的基础,它在合成孔径雷达系统和成像算法的研究中,具有十分重要的作用。模拟算法的优劣直接影响着模拟产生的回波信号的真实性,本论文对模拟算法进行了较为全面和深入的研究。 本论文侧重条带SAR、聚束SAR和多极化SAR的回波信号模拟研究,选择机载和星载两种轨道模型,涉及点目标、面目标、分布目标和真实场景4种目标模型,采用时域、频域和时频域模拟方法,推导出了相应的回波信号模拟公式。 论文的主要贡献和创新是: (1) 设计和研制了星载SAR点目标模拟信号源。在进行回波信号模拟中,卫星轨道采用椭圆轨道模型,目标模型采用椭球体模型,模拟环境更加接近真实情况。距离向实现了单个点目标数据模拟,方位向可以模拟单个点目标、多个点目标,从而能够产生单个点目标和多个点目标的回波信号。该模拟信号源已经投入实际应用当中,参与星载SAR系统的集成测试,用于衡量系统响应函数的空间特性(距离向和方位向的分辨率)和旁瓣特性(峰值旁瓣比和积分旁瓣比),同时用于系统BAQ压缩算法的评估和成像算法的研究。 (2) 提出了全极化星载SAR分布目标原始数据模拟方法。传统的极化数据模拟研究主要采用理想化的目标模型和简单的SAR成像几何关系,本文采用椭圆轨道模型和椭球体模型,使得目标模型和成像几何关系更加接近真实情况。将小平面理论和极化理论结合在一起,推导了全极化模拟计算公式,给出了全极化星载SAR分布目标原始数据模拟方法。 (3) 研究了原始数据的频域模拟方法,在此基础上,提出了真实场景原始数据模拟方法。该方法的提出,一方面解决了真实场景模拟的速度问题;另一方面通过真实场景模拟试验说明利用频域模拟方法实现真实场景模拟的正确性。真实场景模拟方法的提出,极大的提高了模拟速度,使得模拟研究跨入了一个新的阶段。 (4) 考虑时域模拟和频域模拟各自的特点,提出了复杂场景时频域模拟方法。将真实场景经频域模拟产生的原始数据与面目标或分布目标经时域模拟产生的原始数据在两维空间进行叠加,产生复杂场景的原始数据。复杂场景原始更多还原

【Abstract】 The echo simulation which is very important to the study of the SAR system and the imaging methods is the foundation of the technology of Synthetic Aperture Radar (SAR) simulation. Because the truth of the echo simulated is directly efflunced by the accuraty of the simulation algorithms, the simulation algorithms are thoroughly studied in this paper.In the paper, the echo simulation studies of strip-map SAR, spotlight SAR and multi-polarization SAR are introduced; airborne and spaceborne orbit models are selected; four target models: point target, facet target, extended target and real scenario target are included; the time-domain, frequency-domain, and time-frequency-domain simulation methods are adopted; and the formulae of the echo simulation are gained.In general, the contribution and innovation of this paper can be summerized as follows:(1) The point target simulator of spaceborne SAR is designed and manufactured. In processing of the echo simulation, the ellipse model and the ellipsoid model are used for satellite orbit and target model respectively, and the simulation is very close to the real case. Range direction can generate one point target, and azimuth direction can generate several point targets. So the echo of one point target or several point targets are generated by the simulator. This simulator has been applied in real work to test the SAR system, and to evaluate the characteristics of the system IRF space-domain (the range resolution and the azimuth resolution) and the side-lobe (the peak-peak side-lobe ratio and the integral side-lobe ratio). At the same time, it can be used to evaluate the system BAQ algorithm and study the imaging algorithm.(2) The method of the polarimatric spaceborne SAR raw data simulation is introduced. The ideal target models and the simple SAR imaging geometry aremainly used in the methods of the traditional polarization raw data simulation. Because the elliptical orbit model and the ellipsoidal target model are used in the paper, the target model and the orbit model are very close to the real circumstances. Combined the facet theory and the polarization theory, the formulae of the multi-polarization simulation are educed, and the method of the multi-polarization spaceborne SAR extended target raw data simulation is presented.(3) A novel method of frequency-domain simulation is introduced, based on this method, and the method of the real scenario raw data simulation is presented. On the one hand, the question of the real scenarios simulation velocity is settled. On the other hand, the validity of the frequency-domain real scenario simulation method is shown by the experiment of the real scenario simulation. After the method of the real scenario simulation is used, the simulation study is pushed to a new phase.(4) Taken both the time-domain and the frequency-domain into account, the method of the complex scenario is brought forward. To obtain the raw data of the complex scenarios, the raw data of the extended targets which are generated through the time-domain simulation method are added to those of the scenarios which are generated through the frequency-domain simulation method. With the complex scenario simulation method presented, the separate status of the time-domain simulation and the frequency-domain simulation are broken, and a new path of the abundant data simulation is inaugurated.(5) The new idea of spotlight SAR raw data simulation is created. Based on the theory of spotlight SAR, the method of spotlight SAR raw data simulation is introduced. The validity of this method is validated by the simulation experiment of the extended targets. By means of this method, the useful data for the spotlight SAR system study is offered and the study of the imaging algorithms is accelerated.更多还原