本文選題：合成孔徑聲納 + MIMO技術(shù)�。� 參考：《電子科技大學(xué)》2014年碩士論文

【摘要】：合成孔徑聲納(Synthetic Aperture Sonar,SAS)是進(jìn)行水下成像探測(cè)的主要技術(shù)手段之一,與SAR系統(tǒng)類似可以在大范圍成像并且擁有恒定的分辨率,擁有其他聲納系統(tǒng)無法比擬的大范圍成像效果。但是,由于水聲環(huán)境的限制,SAS一直受到測(cè)繪效率低等問題的困擾。本文結(jié)合MIMO新體制研究合成孔徑聲納系統(tǒng),旨在提高SAS系統(tǒng)的測(cè)繪效率,使得其效能可以在實(shí)際運(yùn)用中更大的發(fā)揮出來。本論文主要集中研究一種新型的雙發(fā)多收合成孔徑聲納技術(shù)。從系統(tǒng)設(shè)計(jì)開始,優(yōu)化原先單發(fā)多收線陣的聲納系統(tǒng)結(jié)構(gòu),研究雙發(fā)多收合成孔徑聲納布陣結(jié)構(gòu),并根據(jù)等效相位中心假設(shè)給出其基本的聲程關(guān)系以及信號(hào)處理流程。由于雙發(fā)射機(jī)的布局,以及信號(hào)之間的正交性,新體制相比原先系統(tǒng)多出一倍的等效相位中心。這使得系統(tǒng)可以在其他條件不變的情況下,每次脈沖周期多獲得一倍的方位向采樣,從而提高了系統(tǒng)的測(cè)繪效率。MIMO合成孔徑技術(shù)的關(guān)鍵是正交發(fā)射波形設(shè)計(jì),保證各組信號(hào)之間沒有干擾。本文主要研究四種典型信號(hào):頻分線性調(diào)頻信號(hào),正負(fù)線性調(diào)頻信號(hào),正交跳頻信號(hào)以及正交編碼信號(hào)。對(duì)它們的正交性進(jìn)行了推導(dǎo)以及仿真,并對(duì)每種信號(hào)的功率譜,匹配濾波結(jié)果進(jìn)行分析。其中通過遺傳算法,對(duì)跳頻信號(hào)對(duì)進(jìn)行了互相關(guān)自相關(guān)聯(lián)合優(yōu)化。并比較了各種正交信號(hào)對(duì)的優(yōu)缺點(diǎn)。推導(dǎo)了雙發(fā)多收合成孔徑聲納回波信號(hào)模型。成像算法是SAS系統(tǒng)信號(hào)處理的核心內(nèi)容,這里對(duì)上述的典型信號(hào)根據(jù)經(jīng)典成像算法進(jìn)行了仿真驗(yàn)證,從成像質(zhì)量上對(duì)新系統(tǒng)的正交發(fā)射信號(hào)進(jìn)行性能評(píng)價(jià)。運(yùn)動(dòng)補(bǔ)償技術(shù)是提高成像質(zhì)量的重要手段,論文從重疊相位中心算法入手研究新系統(tǒng)下的像差校正。并給出仿真結(jié)果。最后將正負(fù)線性調(diào)頻信號(hào)多普勒頻移性質(zhì)運(yùn)用于水下強(qiáng)點(diǎn)目標(biāo)相對(duì)速度測(cè)定以及定位技術(shù)。該技術(shù)可以僅通過一次回波信息對(duì)聲納孔徑范圍內(nèi)的水底靜止目標(biāo)進(jìn)行相對(duì)定位,通過利用正線性調(diào)頻信號(hào)與負(fù)線性調(diào)頻信號(hào)在脈沖壓縮時(shí)對(duì)于相同多普勒頻移時(shí)的不同方向的主瓣偏移測(cè)量回波信號(hào)的多普勒頻移,從而測(cè)定相對(duì)速度,結(jié)合脈沖壓縮得到的聲程信息即可進(jìn)行目標(biāo)定位,使得合成孔徑聲納的探測(cè)目標(biāo)的定位更加精確。
[Abstract]:Synthetic Aperture Sonar Sas (synthetic Aperture Sonar) is one of the main techniques for underwater imaging detection. Similar to SAR system, it can be imaged in a large range and has constant resolution, and has a large range imaging effect that other sonar systems can't compare with other sonar systems. However, because of the limitation of underwater acoustic environment, SAS has been troubled by low mapping efficiency. The purpose of this paper is to improve the mapping efficiency of SAS system and make it more effective in practical application by combining the new MIMO system with synthetic aperture sonar system. This paper focuses on a novel dual-transmitter multi-receiver synthetic aperture sonar technology. Starting from the design of the system, the structure of the sonar system with single transmitter and multi-receiver linear array is optimized, and the structure of the dual-transmit multiple-receiver synthetic aperture sonar array is studied. The basic acoustic path relationship and signal processing flow are given according to the assumption of the equivalent phase center. Due to the layout of the dual transmitters and the orthogonality between the signals, the new system has twice as many equivalent phase centers as the original system. This makes it possible for the system to obtain more than one time azimuth sampling for each pulse period without any other conditions, thus improving the mapping efficiency of the system. The key to MIMO synthetic aperture technology is the design of orthogonal transmitting waveforms. Make sure there is no interference between the signals. This paper mainly studies four kinds of typical signals: frequency division linear frequency modulation signal, positive and negative linear frequency modulation signal, quadrature frequency hopping signal and orthogonal coded signal. The orthogonality of each signal is deduced and simulated, and the power spectrum and matched filtering results of each signal are analyzed. The genetic algorithm is used to optimize the frequency hopping signal pair by cross correlation autocorrelation. The advantages and disadvantages of various orthogonal signal pairs are compared. The model of double-transmit multi-receiving synthetic aperture sonar echo signal is derived. The imaging algorithm is the core of signal processing in SAS system. In this paper, the typical signal is simulated according to the classical imaging algorithm, and the performance of the quadrature transmitted signal of the new system is evaluated in terms of imaging quality. Motion compensation is an important method to improve the imaging quality. This paper studies the aberration correction in the new system based on the overlapping phase center algorithm. The simulation results are given. Finally, the Doppler frequency shift property of positive and negative LFM signals is applied to the determination of relative velocity of underwater strong spot target and positioning technology. This technique can locate the underwater static target in the range of sonar aperture by only one echo information. The Doppler frequency shift of echo signal is measured by using positive linear frequency modulation signal and negative linear frequency modulation signal during pulse compression for different directions of the same Doppler frequency shift, so as to determine the relative velocity. Combined with the acoustic path information obtained by pulse compression, target location can be carried out, which makes the target location of synthetic aperture sonar more accurate.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TB566

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 武其松;邢孟道;劉保昌;保錚;;面陣MIMO-SAR大測(cè)繪帶成像[J];電子學(xué)報(bào);2010年04期

2 江澤林;劉維;李保利;劉紀(jì)元;張春華;;基于集群的高頻合成孔徑聲納并行處理方法[J];應(yīng)用聲學(xué);2011年03期

相關(guān)碩士學(xué)位論文 前1條

1 吳鵬;基于運(yùn)動(dòng)補(bǔ)償?shù)暮铣煽讖铰暭{波束形成算法研究[D];武漢理工大學(xué);2009年

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本文編號(hào)：1786591