【摘要】：星載合成孔徑雷達(Synthetic Aperture Radar,SAR)不受領(lǐng)土領(lǐng)空限制,可以全天候、全天時地對地面廣大區(qū)域進行高分辨成像,已經(jīng)成為情報獲取的重要手段和電子戰(zhàn)的重點作戰(zhàn)對象。因此,圍繞星載SAR的有源干擾與抗干擾技術(shù)也成為雷達電子戰(zhàn)領(lǐng)域研究的熱點之一。本文以此為著眼點,以理論分析和仿真試驗相結(jié)合為手段,深入研究了星載SAR的工作參數(shù)估計、欺騙干擾信號生成、星載SAR抗干擾技術(shù)。論文的主要工作包括以下三個部分:本文第一部分研究了SAR工作參數(shù)的偵察與估計方法,具體研究內(nèi)容包括:(1)分析了星載SAR旁瓣偵察雷達方程。根據(jù)這個雷達方程,建立了SAR天線方向圖參數(shù)估計優(yōu)化模型。利用先驗信息,推導(dǎo)了SAR天線尺寸和俯仰向指向角可能存在的區(qū)間,結(jié)合粒子群優(yōu)化算法實現(xiàn)對優(yōu)化模型的求解;(2)針對現(xiàn)有線性調(diào)頻信號(Linear Frequency Modulation,LFM)參數(shù)估計方法計算量較大且低信噪比估計性能較差等不足,提出了一種結(jié)合相關(guān)解線調(diào)和分數(shù)階傅里葉變換的LFM參數(shù)估計方法,該方法避免了參數(shù)搜索的過程,利用奇異值分解來抑制了噪聲的影響;(3)分析了傳統(tǒng)循環(huán)互相關(guān)法估計脈沖時延精度受限的原因,提出了Radon-循環(huán)互相關(guān)脈沖時延估計法、該方法先將多個不同時延的信號循環(huán)互相關(guān)組成二維圖像,再對圖像進行Radon變換,從而將時延估計問題轉(zhuǎn)換為直線參數(shù)估計問題,時延估計精度優(yōu)于傳統(tǒng)循環(huán)互相關(guān)法。第二部分研究了虛假大場景欺騙干擾信號快速生成方法,具體研究內(nèi)容包括:(1)根據(jù)距離多普勒成像算法的原理,提出了基于逆距離多普勒算法的干擾信號生成方法;根據(jù)對干擾實時性的不同要求,對假目標的距離徙動做出不同程度的簡化,推導(dǎo)了這種簡化對干擾效果的影響,分析了相應(yīng)的計算量;(2)根據(jù)距離徙動成像算法的原理,提出了基于逆距離徙動算法的干擾信號生成方法,給出了算法的實現(xiàn)步驟,分析了算法的計算量。該方法生成的干擾信號精度最高,適用于對抗高分辨率和大斜視SAR;(3)為了保護運動軍事目標,提出了勻速運動虛假場景干擾信號生成方法。推導(dǎo)了靜止目標回波與運動目標回波之間的轉(zhuǎn)換關(guān)系,給出了將靜態(tài)場景回波快速轉(zhuǎn)換為勻速運動場景干擾信號的具體步驟;(4)分析了載頻、SAR飛行速度和距離等參數(shù)偵測誤差對干擾效果的影響。詳細推導(dǎo)了不同參數(shù)條件下,脈沖重復(fù)間隔測量誤差對假目標的位置、分辨率和峰值強度的影響。這些結(jié)論將有助于干擾機的研制和應(yīng)用。第三部分研究了雙通道和極化SAR的抗干擾方法,具體研究內(nèi)容包括:(1)提出了一種簡單且易實現(xiàn)的數(shù)據(jù)采集方式,給出了相應(yīng)的回波與干擾信號模型。根據(jù)干擾機與SAR的幾何關(guān)系,推導(dǎo)了干擾信號到達角與方位慢時間的關(guān)系式,提出了干擾源高精度定位方法。利用雙通道對消技術(shù)去除干擾信號,推導(dǎo)了對消前后干信比的變化公式,建立壓縮感知線性測量模型,實現(xiàn)對消后照射場景的高分辨重構(gòu)。(2)根據(jù)壓制干擾和真實回波經(jīng)距離壓縮之后不同的分布特征,提出了基于最小熵準則的壓制干擾抑制方法。利用干擾機和真實目標不同的極化特征,提出了在距離多普勒域?qū)ο麎褐聘蓴_的方法。集成上述兩種方法,可同時抑制壓制干擾和欺騙干擾,推導(dǎo)了抑制后成像結(jié)果。這三種方法雖然可以有效抑制干擾,但卻不同程度地損失了目標的極化信息。
[Abstract]:The Spaceborne Synthetic Aperture Radar (SAR) is not limited by the territory's airspace. It can carry out high-resolution imaging on the vast area of the ground all the time, and has become an important means of information acquisition and the key combat object of the electronic warfare. Therefore, the active jamming and anti-jamming technology around the spaceborne SAR also become one of the hot spots in the field of radar electronic warfare. In this paper, based on the combination of the theory analysis and the simulation test, the work parameter estimation of the spaceborne SAR, the generation of the deception jamming signal and the anti-jamming technology of the spaceborne SAR are studied. The main work of the thesis consists of three parts: the first part of this paper studies the method of reconnaissance and estimation of SAR working parameters, and the specific research contents include: (1) analyzing the radar equation of the SAR side-lobe of the spaceborne SAR. According to this radar equation, the parameter estimation and optimization model of SAR antenna pattern is established. By using the prior information, the interval between the size and pitch of the SAR antenna is derived, and the optimization model is solved by combining the particle swarm optimization algorithm; and (2) for the existing linear frequency modulation (LFM) signal, The LFM parameter estimation method has the advantages of large calculation amount and poor estimation performance of low signal-to-noise ratio, and provides an LFM parameter estimation method combining the correlation solution line and the fractional Fourier transform, which avoids the process of parameter searching, and uses the singular value decomposition to suppress the influence of noise; and (3) analyzing the reason that the accuracy of the pulse time delay is limited by the traditional circular cross-correlation method, and a Radon-cycle cross-correlation pulse time delay estimation method is proposed, So that the time delay estimation problem is converted into a linear parameter estimation problem, and the time delay estimation precision is better than that of the traditional circular cross-correlation method. The second part studies the fast generating method of the false-large-scene deception jamming signal, which includes: (1) according to the principle of the distance-Doppler imaging algorithm, the method of generating the interference signal based on the inverse distance-Doppler algorithm is put forward; and according to the different requirements for the real-time performance of the interference, In this paper, the influence of the simplification on the interference effect is derived, and the corresponding calculation amount is analyzed. (2) The method for generating the interference signal based on the inverse distance interpolation algorithm is proposed based on the principle of the distance-based moving imaging algorithm. The implementation step of the algorithm is given, and the calculation amount of the algorithm is analyzed. The method has the advantages of high precision of the interference signal generated by the method, and is suitable for the SAR with high resolution and strabismus; and (3) in order to protect the moving military target, a method for generating a uniform motion false scene interference signal is proposed. The conversion relation between the stationary target echo and the moving target echo is derived, the concrete steps of fast converting the static scene echo into a uniform motion scene interference signal are given, and (4) the influence of the carrier frequency, the SAR flying speed and the distance and other parameters detection errors on the interference effect is analyzed. The influence of pulse repetition interval measurement error on the position, resolution and peak intensity of false target is derived in detail. These conclusions will contribute to the development and application of the jammer. The third part studies the anti-jamming method of dual-channel and polarized SAR, which includes: (1) a simple and easy-to-implement data acquisition mode is proposed, and the corresponding model of echo and interference signal is given. According to the relationship between the interference machine and the SAR, the relation between the arrival angle and the azimuth slow time of the interference signal is derived, and the high-precision positioning method of the interference source is put forward. By using the dual-channel cancellation technique to remove the interference signal, the formula of the change of the before-and-back dry-signal ratio is derived, and a compression-sensing linear measurement model is established to realize the high-resolution reconstruction of the post-cancellation radiation scene. And (2) according to the different distribution characteristics after the compression interference and the true echo are compressed by the distance, a method for suppressing the suppression interference based on the minimum entropy criterion is proposed. Using the different polarization characteristics of the jammer and the real target, a method to eliminate the interference from the Doppler domain is proposed. By integrating the above two methods, the suppression interference and the deception jamming can be suppressed at the same time, and the post-suppression imaging result is derived. Although the three methods can effectively suppress the interference, the polarization information of the target is lost to a different degree.
【學位授予單位】：國防科學技術(shù)大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN974;V443.2

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本文編號：2488518