發(fā)布時間：2018-03-10 12:54

  本文選題：空時自適應處理　切入點：任意形狀海底　出處：《西北工業(yè)大學》2014年博士論文　論文類型：學位論文

【摘要】：對于淺海混響下主動自導系統(tǒng)來講，混響主要來自海底和海面�；祉懽鳛闇\海自導系統(tǒng)特有的干擾，對水聲信號檢測性能的影響日趨凸顯，由于混響和目標回波具有很強的相關性，對混響抑制一直是水聲信號處理研究中的熱點和難點。本文研究了淺海混響中主動自導系統(tǒng)空時自適應處理技術，該研究屬于水聲信號處理領域的學術前沿，具有重要的理論意義和應用價值。 主動自導系統(tǒng)一個重要的特征是其運動引起的混響多普勒擴展，且這種擴展與雷達的雜波譜擴展特性非常相似，空時自適應處理方法抑制雷達雜波的效果理想，因此，對淺海環(huán)境中自導系統(tǒng)混響的抑制可以借鑒這樣成熟的雜波抑制技術。針對自導系統(tǒng)在淺海環(huán)境下的應用條件，采用空時自適應算法對來自任意海底和海面的混響進行抑制。本文主要研究成果與創(chuàng)新點如下： 1、建立了任意形狀海底的混響譜模型。針對海底凹凸不平的實際情況，用曲面方程描述實際海底形狀，通過牛頓迭代法求出海底任意點的坐標，根據(jù)海底單元與主動自導系統(tǒng)的相對位置關系和方位信息計算不同多普勒單元的混響大小與發(fā)射信號能量譜卷積得到任意海底混響譜，解決了現(xiàn)有的模型將海底統(tǒng)一看作平面建模帶來的不足，進一步推導給出了譜模型的簡化計算方法。從混響衰減曲線、混響級、概率分布以及頻域和空間相關性多個方面對混響特性進行了分析，從仿真分析和誤差對比驗證了譜模型的正確性。 2、建立了海面混響模型。研究了海面混響特性及形成機理，考慮到海面的動態(tài)變化即譜的分布，，優(yōu)化提出了動態(tài)海面分形模型。推導并給出了海面散射強度的表達式以及在不同海面因素作用下具體的海面散射強度計算公式。通過仿真分析驗證了各因素對散射強度的影響及變化規(guī)律。 3、研究了主動自導系統(tǒng)的混響特性。推導了主動自導系統(tǒng)淺海混響的空時分布，仿真驗證了自導系統(tǒng)在不同安裝角度下混響分布特性。通過對STAP混響抑制方法及空時最優(yōu)處理性能的研究，得到可通過低階的空間近似全維數(shù)據(jù)空間或者向低維的子空間投影，實現(xiàn)降維處理。針對空時最優(yōu)處理中協(xié)方差矩陣估計計算量大、難以實現(xiàn)等問題，對主動自導系統(tǒng)的混響自由度進行了分析，同時給出了混響子空間維數(shù)的計算方法，為空時自適應降維研究提供基礎。 4、研究了主動自導系統(tǒng)降維STAP混響抑制。深入研究了TSA、M-CAP空時自適應降維算法，從改善因子、運算量、數(shù)據(jù)采樣、實現(xiàn)復雜度等各方面分析了降維算法與最優(yōu)處理相比的優(yōu)劣性。仿真給出了不同降維算法的空時處理結果及改善因子曲線。為研究新的STAP降維混響抑制方法奠定基礎。 5、提出了基于信息熵的STAP混響抑制方法。在對空時降維算法的研究基礎上，引入了信息熵概念做特征數(shù)據(jù)壓縮，根據(jù)特征值分解后目標與混響所表現(xiàn)出的特性不同，對采集的空時二維數(shù)據(jù)進行數(shù)據(jù)選擇，通過仿真對算法進行分析驗證。 6、提出了基于信息熵的降維STAP混響抑制方法。針對基于信息熵的STAP混響抑制方法中特征值分解帶來的算法復雜度增加問題對算法進行了改進。在信息熵數(shù)據(jù)提取的基礎上，對接收的數(shù)據(jù)進行子數(shù)組劃分，然后做空時平滑處理來估計協(xié)方差矩陣，原始的空時處理器維數(shù)由NK變?yōu)镻Q，其中（P N, QK），根據(jù)最小線性約束準則求得自適應權向量，對目標檢測數(shù)據(jù)采用大小為PQ的空時窗用權矢量平滑加權輸出。 7、對基于信息熵的降維STAP混響抑制方法進行了實測數(shù)據(jù)的實驗驗證。從原始數(shù)據(jù)的采集到最后的輸出處理作了詳細的分析，實驗分析結果表明該算法可以在降低計算量的同時較好的檢測出目標。 8、針對本文所建的任意形狀海底混響模型，采用基于信息熵的降維STAP算法進行任意海底混響抑制。用曲面方程對海底平面進行模擬，通過牛頓迭代算法得到曲面方程解計算不同位置的方位和俯仰角。根據(jù)仿真得到的混響空時分布結果，采用基于信息熵的降維STAP方法，計算混響協(xié)方差矩陣和權矢量并總結了海底混響抑制的步驟。仿真分析驗證了任意海底形狀在不同的曲面方程下混響級、多普勒頻率的變化規(guī)律及空時輸出結果。 9、針對本文所建的海面混響模型，采用基于信息熵的降維STAP算法進行海面混響抑制。在動態(tài)海面模型基礎上，分析了不同因素對海面混響的影響及不同因素作用下自導系統(tǒng)的海面混響空時譜和功率譜分布特性。根據(jù)仿真得到不同因素作用下的混響空時分布，將海面劃分為粗糙面作用與含氣泡粗糙面作用兩種情況，給出了兩種方式下的海面空時處理結果。
[Abstract]:For under the shallow water reverberation active homing system, mainly from the seabed and surface reverberation. The reverberation in shallow water as homing interference system peculiar to the influence on the acoustic signal detection performance is becoming increasingly prominent, because the reverberation and target echo has a strong correlation, the reverberation suppression is a hot and difficult research of underwater acoustic signal processing in this paper. The active homing system of space-time adaptive processing technology in the study of shallow water reverberation, which belongs to the academic frontier in the field of underwater signal processing, and has important theoretical significance and application value.
One of the important features of the active homing system is its motion caused by reverberation Doppler expansion, and the expansion of clutter and radar propagation is very similar to that of the ideal, the effect of space time adaptive processing for clutter suppression and clutter suppression technology that can learn from the mature inhibition of homing system reverberation in shallow water. According to the application conditions in shallow water environment system, the space-time adaptive algorithm of arbitrary seabed and surface reverberation suppression. The main research achievements and innovations are as follows:
1, any shape of the sea floor reverberation spectrum model is established. According to the actual situation of the uneven seabed, seabed shape with a description of the actual surface equation, using the Newton iteration method is used to calculate the coordinates of any point of the seabed, according to the unit and the active homing system of the relative position and position information to calculate the different Doppler unit size and reverberation signal the energy spectrum obtained by convolution with arbitrary reverberation spectrum, the solution of the existing model will be unified as lack of submarine plane modeling brings, further calculation method was deduced. The simplified spectrum model of reverberation attenuation curve, a reverberation level, probability distribution, frequency and spatial correlation analysis of reverberation characteristics, correct spectrum the model was verified through simulation analysis and error analysis.
2, establish the model of sea surface reverberation. The reverberation characteristics and formation mechanism, considering the dynamic changes of the sea spectrum distribution, optimize the proposed dynamic sea fractal model. The expression is given the scattering intensity as well as in different sea factors specific sea surface scattering strength calculation formula is verified by simulation. The influence of scattering intensity and the variation of various factors.
3, study the characteristics of reverberation active homing system. Deduced the active homing system of the reverberation time distribution, simulation of the distribution of the reverberation homing system in different installation angle characteristics. By inhibiting the study of optimal method and space-time processing performance of STAP reverberation can be obtained by low order spatial approximation of the full dimensional data space or to a low dimensional subspace projection, realize dimensionality reduction. According to the covariance matrix of the estimated optimal processing time of large amount of calculation, it is difficult to achieve such problems, the reverberation freedom active homing system are analyzed, and gives the calculation method of reverberation subspace dimension, provides the basis for the study of adaptive dimension reduction. When.
4, on the active homing system dimension STAP reverberation suppression. Research TSA, M-CAP space-time adaptive dimensionality reduction algorithm, the improvement factor, the amount of computation, data sampling, the realization of the complexity analysis of the advantages and disadvantages of drop compared with the optimal processing dimension algorithm. Simulation is given with dimensionality reduction algorithm the space-time processing results and improvement factor curve. Lay the foundation for the study of new STAP suppression method for dimensionality reduction reverberation.
5, propose a method to suppress the reverberation based on information entropy STAP. Based on the study of space-time dimensionality reduction algorithm, introduces the concept of information entropy feature data compression, according to the characteristics of value target and reverberation decomposition showed different space-time data acquisition of data selection, based on the simulation analysis and test.
6, propose a method to suppress the dimension reduction STAP reverberation based on information entropy. The information entropy method in STAP reverberation suppression eigenvalue decomposition caused by increasing the complexity of the algorithm of the algorithm is improved. Based on the information entropy of data extraction, the received data are the number of sub groups, and then short smooth to estimate the covariance matrix, the original space-time processor dimension changed from NK to PQ, which (P N, QK), according to the minimum standards for linearly constrained adaptive weight vector, the target detection data with the size of PQ space-time window smoothing weight vector weighted output.
7, the experimental verification of the reduced dimension STAP reverberation suppression method based on information entropy is carried out. The data from the raw data acquisition to the final output processing are analyzed in detail. The experimental results show that the algorithm can detect the target better while reducing the amount of computation.
8, for any shape of reverberation in the model, the reduced dimension STAP algorithm based on information entropy of arbitrary reverberation suppression. The plane was simulated by the curve equation by the Newton iterative algorithm is calculated in different position of the azimuth and elevation angle. According to the distribution of solution surface equation results obtained by the simulation of the reverberation time. The STAP dimension reduction method based on information entropy calculation of reverberation covariance matrix and weight vector and summarizes the reverberation suppression process. Simulation and analysis verify the seafloor reverberation in arbitrary shape curved surface equation under different level, the output variation and empty Doppler frequency.
9, according to the new surface reverberation model, using STAP dimensionality reduction algorithm based on information entropy of surface reverberation suppression. Based on dynamic surface model, analyzes the influence of different factors on the effect of different factors of surface reverberation and homing system of sea surface reverberation space-time spectrum and power spectrum distribution characteristics. According to the simulation result under the action of different factors of reverberation space-time distribution, the sea is divided into rough surface and rough surface with bubbles two, gives two ways under the sea the space-time processing.

【學位授予單位】：西北工業(yè)大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN911.23

【參考文獻】

相關期刊論文 前10條

1 陶建武,常文秀,石要武;遞推式空時自適應濾波器的研究[J];兵工學報;2004年05期

2 柳輝;;解非線性方程的牛頓迭代法及其應用[J];重慶工學院學報(自然科學版);2007年08期

3 劉勝;楊成渝;王平義;;水中氣泡運動規(guī)律的研究[J];重慶交通學院學報;2007年03期

4 魯遠耀;張平;李國春;;雙基雷達空時自適應處理中的雜波特性[J];測試技術學報;2005年04期

5 徐凱,紀紅,樂光新;一種改進的變步長自適應濾波器LMS算法[J];電路與系統(tǒng)學報;2004年04期

6 張俊敏;;基于改進型自適應算法的諧波檢測及其性能研究[J];電力自動化設備;2011年04期

7 梁紅,李志舜,王惠剛;一種變步長自適應格型IIR陷波器及其在混響抵消中的應用研究[J];電聲技術;2004年02期

8 徐麥容;劉成云;;水中浮升氣泡的半徑和速度變化[J];大學物理;2008年11期

9 段銳;汪學剛;陳祝明;江朝抒;;雙基機載雷達幾何場景建模及空時雜波特性仿真[J];電子測量與儀器學報;2009年02期

10 張世平,趙永平,張紹卿,李德勝;一種改進的自適應格型陷波算法及其收斂性分析[J];電子學報;2004年02期

相關博士學位論文 前4條

1 張增輝;天基雷達空時自適應雜波抑制技術[D];國防科學技術大學;2008年

2 高偉;淺�；祉懡y(tǒng)計反演海底聲參數(shù)和界面統(tǒng)計參數(shù)研究[D];中國海洋大學;2008年

3 沈明威;和差波束空時處理動目標檢測技術研究[D];南京航空航天大學;2008年

4 龔偉;基于信息熵和互信息的流域水文模型不確定性分析[D];清華大學;2012年

本文編號：1593428