基于二维频谱的双站SAR成像技术研究
发布时间：2018-10-21 18:02
【摘要】：相比于单站SAR,双站SAR在军事应用、干涉应用、对地物的分类识别,以及在海洋应用等领域具有很多单站SAR所不具有的优势,因此双站SAR成像算法的研究具有很高的应用价值。本文围绕双站SAR的基本构型,重点讨论了双站SAR中的二维频谱成像算法问题。本文的研究内容大概可以归类为如下几点:在双站SAR成像领域中,点目标的二维频谱求解算法是其中最重要的一个问题。本文在双站SAR回波模型的基础上,首先回顾了经典的双站SAR二维频谱求解算法,并简化的推导了EEFT4二维频谱求解算法,分析了其可行性以及误差。推导了一种基于正交多项式最佳平方逼近的双站SAR二维频谱算法。通过将信号处理中最佳平方逼近的原理应用于斜距历程的展开中,并保留到四阶项。该算法相比其他算法具有能使斜距历程误差积累达到最小的特点。然后将本文推导的基于正交多项式最佳平方逼近的双站SAR二维频谱算法与LBF、ILBF两种算法进行比较,从而验证了该频谱算法的可行性。推导了基于MSR二维频谱表达式的双站ωk成像算法,分析了在实际应用中高精度要求下,MSR成像算法精度与算法复杂度之间的矛盾关系。并在其基础上引入了高阶对消项从而使低阶展开情况下的二维频谱与回波频谱更加匹配。在降低算法复杂度的基础上提升了算法的聚焦性能,减少了高阶残余项对成像的影响。提出一种双站微增量二维频谱算法,前面提到的算法如MSR算法虽然可以通过控制展开阶数从而得到理想的精度,但是却存在表达式复杂不易推导的情况。而该双站微增量二维频谱算法通过分析低阶和高阶驻定相位点间增量变换关系,从而巧妙的通过低阶驻定相位点求取高阶相位点的近似解。在此二维频谱的基础上,通过对其相位进行距离变量的分解以及Stolt变换,得到了一种基于双站微增量二维频谱的ωk算法。由于在ωk算法中运用了角度不变假设,重点分析了不变区域的大小,并进行仿真实验以验证该算法的可行性。
[Abstract]:Compared with single-station SAR, bistatic SAR in military applications, interference applications, classification and recognition of ground objects, and ocean applications, bistatic SAR imaging algorithm has many advantages that the single-station SAR does not have, so the study of bistatic SAR imaging algorithm has a high application value. Focusing on the basic configuration of bistatic SAR, this paper focuses on the two dimensional spectral imaging algorithm in bistatic SAR. In the field of bistatic SAR imaging, the algorithm of solving the two-dimensional spectrum of point target is one of the most important problems. Based on the bistatic SAR echo model, this paper first reviews the classical bistatic SAR two-dimensional spectrum solution algorithm, and deduces the EEFT4 two-dimensional spectrum solution algorithm, and analyzes its feasibility and error. A bistatic SAR 2-D spectrum algorithm based on optimal square approximation of orthogonal polynomials is derived. The principle of the best square approximation in signal processing is applied to the development of the oblique distance process, and the term of fourth order is retained. Compared with other algorithms, this algorithm can minimize the error accumulation of oblique distance history. Then, the bistatic SAR 2-D spectrum algorithm based on the best square approximation of orthogonal polynomials is compared with the LBF,ILBF algorithm, which verifies the feasibility of the proposed algorithm. A bistatic 蠅 k imaging algorithm based on MSR 2-D spectrum expression is derived. The contradiction between the accuracy of MSR imaging algorithm and the complexity of the algorithm is analyzed under the requirement of high accuracy in practical applications. On the basis of this, a higher order cancellation term is introduced to match the two dimensional spectrum and the echo spectrum in the case of low order expansion. On the basis of reducing the complexity of the algorithm, the focus performance of the algorithm is improved, and the influence of high-order residual terms on the imaging is reduced. A bistatic micro-increment two-dimensional spectrum algorithm is proposed. The algorithms mentioned above, such as the MSR algorithm, can obtain the ideal precision by controlling the expansion order, but the expression is complicated and difficult to be deduced. The bistatic micro-increment two-dimensional spectrum algorithm is based on the analysis of the incremental transformation relationship between the low-order and high-order stationary phase points, so as to obtain the approximate solution of the high-order phase points through the low-order stationary phase points. On the basis of the two dimensional spectrum, the 蠅 k algorithm based on the bistatic microincrement two-dimensional spectrum is obtained by the decomposition of the phase distance variable and the Stolt transform. Because the assumption of angle invariance is used in 蠅 k algorithm, the size of invariant region is analyzed, and the simulation experiment is carried out to verify the feasibility of the algorithm.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.52
[Abstract]:Compared with single-station SAR, bistatic SAR in military applications, interference applications, classification and recognition of ground objects, and ocean applications, bistatic SAR imaging algorithm has many advantages that the single-station SAR does not have, so the study of bistatic SAR imaging algorithm has a high application value. Focusing on the basic configuration of bistatic SAR, this paper focuses on the two dimensional spectral imaging algorithm in bistatic SAR. In the field of bistatic SAR imaging, the algorithm of solving the two-dimensional spectrum of point target is one of the most important problems. Based on the bistatic SAR echo model, this paper first reviews the classical bistatic SAR two-dimensional spectrum solution algorithm, and deduces the EEFT4 two-dimensional spectrum solution algorithm, and analyzes its feasibility and error. A bistatic SAR 2-D spectrum algorithm based on optimal square approximation of orthogonal polynomials is derived. The principle of the best square approximation in signal processing is applied to the development of the oblique distance process, and the term of fourth order is retained. Compared with other algorithms, this algorithm can minimize the error accumulation of oblique distance history. Then, the bistatic SAR 2-D spectrum algorithm based on the best square approximation of orthogonal polynomials is compared with the LBF,ILBF algorithm, which verifies the feasibility of the proposed algorithm. A bistatic 蠅 k imaging algorithm based on MSR 2-D spectrum expression is derived. The contradiction between the accuracy of MSR imaging algorithm and the complexity of the algorithm is analyzed under the requirement of high accuracy in practical applications. On the basis of this, a higher order cancellation term is introduced to match the two dimensional spectrum and the echo spectrum in the case of low order expansion. On the basis of reducing the complexity of the algorithm, the focus performance of the algorithm is improved, and the influence of high-order residual terms on the imaging is reduced. A bistatic micro-increment two-dimensional spectrum algorithm is proposed. The algorithms mentioned above, such as the MSR algorithm, can obtain the ideal precision by controlling the expansion order, but the expression is complicated and difficult to be deduced. The bistatic micro-increment two-dimensional spectrum algorithm is based on the analysis of the incremental transformation relationship between the low-order and high-order stationary phase points, so as to obtain the approximate solution of the high-order phase points through the low-order stationary phase points. On the basis of the two dimensional spectrum, the 蠅 k algorithm based on the bistatic microincrement two-dimensional spectrum is obtained by the decomposition of the phase distance variable and the Stolt transform. Because the assumption of angle invariance is used in 蠅 k algorithm, the size of invariant region is analyzed, and the simulation experiment is carried out to verify the feasibility of the algorithm.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.52
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