基于星载照射源的BSAR同步、成像及干涉应用技术研究

发布时间：2018-06-29 17:00

本文选题：合成孔径雷达 + 双基地合成孔径雷达　；参考：《国防科学技术大学》2014年博士论文

【摘要】：基于星载照射源的双基地合成孔径雷达(Bistatic Synthetic Aperture Radar,BSAR)是指利用已在轨卫星(包括SAR卫星、导航卫星、通信卫星等)作为发射机,采用其它平台(包括飞艇、飞机、汽车及固定站等)搭载接收机的雷达系统,具有成本低廉、配置灵活、战场生存能力强等技术优势,是目前的前沿和热点研究方向。本论文具体涉及两种不同的配置:基于导航卫星的BSAR和基于SAR卫星的BSAR。其中,基于导航卫星的BSAR系统是指利用在轨导航卫星作为发射机,采用近地静止平台搭载接收机的BSAR系统;基于SAR卫星的BSAR系统是指利用已在轨的星载SAR系统作为发射机,采用飞艇平台搭载接收机的BSAR系统。本文结合理论研究与工程应用,针对上述两种配置的BSAR系统在同步、成像以及干涉应用技术上存在的共性问题和特殊问题开展了深入的研究。本文的主要研究工作可以概括如下:1.研究了基于星载照射源的BSAR系统概念与特性,并进行了对比和分析,为进一步的信号处理与干涉应用研究奠定了理论基础。(1)论述了基于导航卫星的BSAR系统概念,并从系统几何构型、信噪比、空间分辨率以及时空覆盖率等方面对其系统特性进行了深入分析。(2)论述了基于SAR卫星的BSAR系统概念,并从系统几何构型、信噪比、空间分辨率以及时空覆盖率等方面对其系统特性进行了深入分析。(3)针对两种系统在信噪比特性和多普勒特性方面的异同,进行了深入的对比与分析,明确了二者的联系与区别。2.针对基于导航卫星的BSAR,研究了其同步与成像方法。具体工作为:(1)推导了系统回波信号模型,并分析了导航信号体制以及相位同步误差的影响。(2)研究了同步预处理方法,实现了导航信息的有效检测和多普勒频率的精确估计,消除了导航信号体制的影响。(3)利用该系统收发几何极度非对称的特性,理论证明了直达波和散射波的距离历程测量误差可以在很大程度上相互抵消的结论。(4)基于测量误差抵消原理,结合时域成像算法,提出了一种同步与成像一体化方法,并利用实测数据验证了所提方法的有效性。3.针对基于SAR卫星的BSAR,研究了其同步与成像方法。具体工作为:(1)采用了一种基于宽波束连续接收体制的空间同步方法,既保证了实验的成功率,又可实现较宽的观测场景覆盖。(2)建立了时、频同步误差模型,分析了时、频同步误差对成像质量的影响。(3)提出了一种时、频同步与成像一体化方法,精确、高效地实现了同步与成像处理。该方法直接利用提取到的直达波信号时延及峰值相位对散射波信号进行补偿,然后利用泰勒级数展开和线性近似推导了同步后场景回波的二维频谱,最后针对二维频谱的特性,提出了一种基于二维ISFT的成像算法,可以满足大场景、高精度的成像要求。4.研究了基于星载照射源的BSAR干涉应用技术。具体工作为:(1)构建了基于星载照射源的BSAR复图像模型,针对干涉应用深入分析了相干系数,从而建立了基于星载照射源的BSAR干涉理论模型。(2)针对基于导航卫星的BSAR相干变化检测应用,首先研究了其技术原理,然后阐述了具体处理方法,最后着重从相干性角度分析了其技术性能。(3)针对基于SAR卫星的BSAR干涉高程测量应用,研究了其技术原理,针对其“立体测高”特性,分析了干涉条纹特性,通过深入分析系统相干性能,最后明确了该技术的相对高程测量精度。本文利用大量仿真数据与实测数据开展了充分的实验验证,从而证明了本文研究成果具有良好的实际应用价值。
[Abstract]:Bistatic Synthetic Aperture Radar (BSAR) based on Spaceborne radiation sources refers to the radar system that uses other platforms (including airships, aircraft, automobiles and fixed stations) that have been used as transmitters by using on orbit satellites (including SAR satellites, navigation satellites, communication satellites, etc.) as transmitters, and is cheap and configured. The technical advantage such as flexibility and strong battlefield survivability is the forward and hot research direction. This paper deals with two different configurations: BSAR based on navigation satellite and BSAR. based on SAR satellite, the BSAR system based on navigation satellite refers to the use of on orbit navigation satellite as a transmitter, and the use of near ground static platform to receive and receive. The BSAR system of the machine; the BSAR system based on the SAR satellite refers to the BSAR system that uses a spaceborne SAR system as the transmitter and the airship platform to carry the receiver. This paper combines the theoretical research and the engineering application to solve the common problems and special problems in the synchronization, imaging and interference application of the above two configuration BSAR systems. The main research work of this paper can be summarized as follows: 1. the concept and characteristics of BSAR system based on Spaceborne radiation source are studied and compared and analyzed, which lays a theoretical foundation for further signal processing and interference application research. (1) the concept of the navigation satellite based BSAR system is discussed and the system is from the system. The geometric configuration, signal to noise ratio, spatial resolution and space-time coverage are deeply analyzed. (2) the concept of BSAR system based on SAR satellite is discussed, and its system characteristics are deeply analyzed from the aspects of system geometry, signal-to-noise ratio, spatial resolution and space-time coverage. (3) two systems are applied to the system. The characteristics of signal-to-noise ratio and Doppler characteristics are compared and analyzed, and the relationship and difference between the two are clarified and the methods of synchronization and imaging for the BSAR based on navigation satellite are studied. The specific work is as follows: (1) the system echo signal model is derived, and the navigation signal system and the phase synchronization error are analyzed. (2) the synchronous preprocessing method is studied, which realizes the effective detection of navigation information and the accurate estimation of the Doppler frequency, and eliminates the influence of the navigation signal system. (3) the theory that the distance measurement error of the direct and scattered waves can be offset to a large extent by using the system's extreme asymmetrical characteristic of receiving and receiving geometry. 4. (4) based on the principle of measurement error cancellation and combined with time domain imaging algorithm, a method of integration of synchronization and imaging is proposed, and the effectiveness of the proposed method is verified by the measured data. The method of synchronization and imaging for BSAR based on SAR satellite is studied. The specific work is: (1) a continuous receiver based on wide beam is adopted. The spatial synchronization method not only ensures the success rate of the experiment, but also realizes the wide observation scene coverage. (2) the time synchronization error model is established, and the influence of frequency synchronization error on the imaging quality is analyzed. (3) a method of integration of frequency synchronization and imaging is proposed, and the synchronization and imaging processing is realized accurately and efficiently. Using the time delay and peak phase of the extracted direct wave signal to compensate the scattered wave signal, then using the Taylor series expansion and the linear approximation to deduce the two-dimensional spectrum of the scene echo after the synchronization. Finally, a two-dimensional ISFT based imaging algorithm is proposed to meet the characteristics of the two-dimensional spectrum, which can satisfy the large scene and high precision. BSAR interference application technology based on Spaceborne radiation source is studied by.4.. The specific work is as follows: (1) a BSAR complex image model based on Spaceborne radiation source is constructed, and the coherence coefficient is deeply analyzed for the interference application, and the BSAR interference theory model based on the spaceborne radiation source is established. (2) the BSAR coherent change based on navigation satellite The technology principle is studied first, and then the specific processing method is discussed. Finally, its technical performance is analyzed from the angle of coherence. (3) in view of the application of BSAR interferometric elevation measurement based on SAR satellite, its technical principle is studied, and the characteristics of the interference fringe are analyzed in view of its "stereo height measurement" characteristics, and the system is deeply analyzed. In the end, the relative height measurement precision of the technology is made clear. This paper uses a lot of simulation data and measured data to carry out full experimental verification, which proves that the research results of this paper have good practical application value.
【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN957.52

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