基于二維頻譜的雙站SAR成像技術(shù)研究
發(fā)布時間：2018-10-21 18:02
【摘要】：相比于單站SAR,雙站SAR在軍事應(yīng)用、干涉應(yīng)用、對地物的分類識別,以及在海洋應(yīng)用等領(lǐng)域具有很多單站SAR所不具有的優(yōu)勢,因此雙站SAR成像算法的研究具有很高的應(yīng)用價值。本文圍繞雙站SAR的基本構(gòu)型,重點討論了雙站SAR中的二維頻譜成像算法問題。本文的研究內(nèi)容大概可以歸類為如下幾點:在雙站SAR成像領(lǐng)域中,點目標(biāo)的二維頻譜求解算法是其中最重要的一個問題。本文在雙站SAR回波模型的基礎(chǔ)上,首先回顧了經(jīng)典的雙站SAR二維頻譜求解算法,并簡化的推導(dǎo)了EEFT4二維頻譜求解算法,分析了其可行性以及誤差。推導(dǎo)了一種基于正交多項式最佳平方逼近的雙站SAR二維頻譜算法。通過將信號處理中最佳平方逼近的原理應(yīng)用于斜距歷程的展開中,并保留到四階項。該算法相比其他算法具有能使斜距歷程誤差積累達(dá)到最小的特點。然后將本文推導(dǎo)的基于正交多項式最佳平方逼近的雙站SAR二維頻譜算法與LBF、ILBF兩種算法進(jìn)行比較,從而驗證了該頻譜算法的可行性。推導(dǎo)了基于MSR二維頻譜表達(dá)式的雙站ωk成像算法,分析了在實際應(yīng)用中高精度要求下,MSR成像算法精度與算法復(fù)雜度之間的矛盾關(guān)系。并在其基礎(chǔ)上引入了高階對消項從而使低階展開情況下的二維頻譜與回波頻譜更加匹配。在降低算法復(fù)雜度的基礎(chǔ)上提升了算法的聚焦性能,減少了高階殘余項對成像的影響。提出一種雙站微增量二維頻譜算法,前面提到的算法如MSR算法雖然可以通過控制展開階數(shù)從而得到理想的精度,但是卻存在表達(dá)式復(fù)雜不易推導(dǎo)的情況。而該雙站微增量二維頻譜算法通過分析低階和高階駐定相位點間增量變換關(guān)系,從而巧妙的通過低階駐定相位點求取高階相位點的近似解。在此二維頻譜的基礎(chǔ)上,通過對其相位進(jìn)行距離變量的分解以及Stolt變換,得到了一種基于雙站微增量二維頻譜的ωk算法。由于在ωk算法中運用了角度不變假設(shè),重點分析了不變區(qū)域的大小,并進(jìn)行仿真實驗以驗證該算法的可行性。
[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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN957.52
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