本文選題：K分布海雜波　切入點(diǎn)：最優(yōu)檢測　出處：《電子科技大學(xué)》2014年碩士論文

【摘要】：海面動(dòng)目標(biāo)的檢測是雷達(dá)信號(hào)處理領(lǐng)域中的一個(gè)研究熱點(diǎn),在民用和軍用方面都占有十分重要的地位。隨著作用距離、多普勒分辨率、距離分辨率、實(shí)時(shí)性、可靠性等要求的提高,如何改善雷達(dá)回波的信雜比,并在強(qiáng)海雜波背景中更有效地檢測出運(yùn)動(dòng)目標(biāo),成為了急待解決的研究問題。本文針對海雜波嚴(yán)重干擾雷達(dá)對低速和高速動(dòng)目標(biāo)檢測的問題,在研究動(dòng)目標(biāo)特性的基礎(chǔ)上,開展了海雜波背景下動(dòng)目標(biāo)檢測及其FPGA實(shí)現(xiàn)技術(shù)的研究。第一,研究和討論了不同海雜波模型的統(tǒng)計(jì)分布特性,分別對艦船等海面低速動(dòng)目標(biāo)以及導(dǎo)彈、飛機(jī)等高速動(dòng)目標(biāo)的回波特性進(jìn)行研究,建立回波模型,并對動(dòng)目標(biāo)的時(shí)域和頻域特性進(jìn)行仿真。第二,針對低速動(dòng)目標(biāo)的多普勒頻移接近海雜波中心頻率的問題,研究了K分布海雜波背景下低速動(dòng)目標(biāo)的最優(yōu)檢測(OD)和廣義似然比檢測(GLRT),深入分析了K分布海雜波形狀參數(shù)、尺度參數(shù)以及相干積累脈沖數(shù)對OD和GLRT算法的影響,利用輔助雜波距離單元估計(jì)海雜波的歸一化協(xié)方差矩陣。在此基礎(chǔ)上,采用特征值分解和多普勒相位空間搜索兩種方法估計(jì)目標(biāo)的多普勒頻移,并對相位搜索GLRT的運(yùn)算量進(jìn)行了改進(jìn)。最后,通過蒙特卡洛仿真試驗(yàn)比較和分析了K分布海雜波背景下OD和GLRT的檢測性能,以及GLRT在方向矢量未知條件下的檢測性能,并采用IPIX海雜波數(shù)據(jù)進(jìn)行處理驗(yàn)證。第三,針對高速動(dòng)目標(biāo)在長時(shí)間相干積累中存在距離走動(dòng)和多普勒模糊現(xiàn)象的問題,深入研究了基于Keystone變換(KT)和Radon-Fourier變換(RFT)的高速動(dòng)目標(biāo)檢測方法。首先,分析和比較了三種不同KT實(shí)現(xiàn)方法對運(yùn)動(dòng)目標(biāo)距離走動(dòng)的補(bǔ)償。其次,基于運(yùn)動(dòng)目標(biāo)的徑向速度、距離走動(dòng)和多普勒頻移之間的耦合關(guān)系,研究了速度和距離聯(lián)合搜索的RFT算法,并對多普勒補(bǔ)償函數(shù)進(jìn)行互補(bǔ)加權(quán),抑制RFT的盲速旁瓣現(xiàn)象。最后,通過大量的蒙特卡洛仿真試驗(yàn)比較和分析Keystone變換和RFT在海雜波背景下海面高速動(dòng)目標(biāo)的檢測性能。第四,在ISE開發(fā)環(huán)境中,對海面低速動(dòng)目標(biāo)的GLRT算法進(jìn)行FPGA仿真,并與MATLAB的仿真結(jié)果相比較。本文研究的方法在低SCR下分別可以有效地檢測出海面低速和高速動(dòng)目標(biāo)。
[Abstract]:The detection of moving targets on the sea surface is a hot topic in radar signal processing, which plays an important role in both civil and military fields. With the improvement of reliability, how to improve the signal-clutter ratio of radar echo and detect moving target more effectively in the background of strong sea clutter, It is an urgent problem to be solved. In this paper, the characteristics of moving targets are studied based on the detection of low speed and high speed moving targets by sea clutter serious jamming radar. The research of moving target detection and its FPGA implementation technology in sea clutter background is carried out. Firstly, the statistical distribution characteristics of different sea clutter models are studied and discussed. The echo characteristics of high-speed moving targets such as aircraft are studied, the echo model is established, and the time-domain and frequency-domain characteristics of moving targets are simulated. Secondly, the Doppler frequency shift of low-speed moving targets is close to the center frequency of sea clutter. The optimal detection of low speed moving targets in the background of K-distributed sea clutter and the generalized likelihood ratio (GML) detection are studied. The effects of shape parameters, scale parameters and the number of coherent integrated pulses on the OD and GLRT algorithms are deeply analyzed. The normalized covariance matrix of sea clutter is estimated by the auxiliary clutter distance unit. On this basis, the Doppler frequency shift of the target is estimated by eigenvalue decomposition and Doppler phase space search. Finally, the detection performance of OD and GLRT under the background of K-distributed sea clutter and the detection performance of GLRT under unknown direction vector are compared and analyzed by Monte Carlo simulation. The IPIX sea clutter data is used to process and verify. Thirdly, aiming at the problems of range walk and Doppler ambiguity in the long time coherent accumulation of high speed moving target, The methods of high speed moving target detection based on Keystone transform (KT) and Radon-Fourier transform (RFT) are studied in depth. Firstly, three different KT realization methods are analyzed and compared to compensate the moving target range walk. Secondly, based on the radial velocity of moving target, The coupling relationship between range walk and Doppler frequency shift is studied. The RFT algorithm of velocity and range joint search is studied, and the complementary weighting of Doppler compensation function is carried out to suppress the blind velocity sidelobe phenomenon of RFT. A lot of Monte Carlo simulation experiments are carried out to compare and analyze the detection performance of Keystone transform and RFT in sea surface high speed moving target under sea clutter background. Fourthly, in the ISE development environment, the GLRT algorithm of low speed moving target is simulated by FPGA. Compared with the simulation results of MATLAB, the method studied in this paper can effectively detect low speed and high speed moving targets at low SCR.
【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(hào)】：TN957.51

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本文編號(hào)：1662948