本文關(guān)鍵詞： 懸浮顆粒濃度 懸浮顆粒粒徑 反向散射回波 多頻反向散射 反演方法　出處：《浙江大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：基于聲學(xué)的水體懸浮顆粒測(cè)量是研究水中懸沙濃度分布、遷移等特征的重要手段。相比于傳統(tǒng)的懸浮顆粒觀測(cè)技術(shù),基于聲學(xué)的方法是一種非干擾式剖面測(cè)量方法,這種方法操作簡(jiǎn)易、測(cè)量數(shù)據(jù)具有較高的空時(shí)分辨力,近年來(lái)受到越來(lái)越多的關(guān)注,但其涉及的聲信號(hào)處理技術(shù)相對(duì)復(fù)雜。論文針對(duì)聲學(xué)反向散射技術(shù)運(yùn)用在水體懸浮顆粒濃度剖面測(cè)量過(guò)程中的若干問(wèn)題開(kāi)展研究,旨在探索有效的懸浮顆粒濃度聲學(xué)反演方法。 聲學(xué)反向散射測(cè)量方法的基本原理為：發(fā)射換能器發(fā)射短時(shí)聲脈沖信號(hào)照射水體,水體內(nèi)懸浮物質(zhì)散射聲能,接收換能器記錄沿著發(fā)射的反方向傳播回來(lái)的回波信號(hào)；回波信號(hào)攜帶了懸浮物質(zhì)的物理特征,通過(guò)聲學(xué)反演的方法可以從中獲取相關(guān)物理特征參數(shù)。在聲學(xué)測(cè)量過(guò)程中需要特別考慮懸浮顆粒自身對(duì)聲波造成的衰減,以及懸浮顆粒大小和濃度對(duì)散射聲能量的聯(lián)合貢獻(xiàn)等問(wèn)題。 論文針對(duì)聲波散射的衰減特性,分別介紹其幾何擴(kuò)展衰減與吸收衰減,并分別從效聲學(xué)截面積和散射形式函數(shù)兩個(gè)方向?qū)腋☆w粒的散射特性進(jìn)行探討。在此基礎(chǔ)上,論文首先以寬帶聲學(xué)多普勒流速剖面儀(Acoustic Doppler Current Pro-filer,簡(jiǎn)稱ADCP)為例,介紹了一種寬帶水體散射回波的構(gòu)建方法,即通過(guò)對(duì)寬帶ADCP測(cè)量過(guò)程中的發(fā)射信號(hào)、聲波傳播過(guò)程的能量變化進(jìn)行分析,在頻率域?qū)Ω鱾�(gè)頻率分量分別進(jìn)行處理,最后利用傅里葉合成重構(gòu)水體的反向散射回波。通過(guò)仿真分析表明該方法構(gòu)建的散射回波在統(tǒng)計(jì)意義的角度與實(shí)測(cè)環(huán)境信號(hào)有較好的一致性。 論文對(duì)基于聲學(xué)反向散射的懸浮顆粒濃度和粒徑的反演方法進(jìn)行了研究,根據(jù)測(cè)量頻率的使用情況將其劃分為單頻和多頻反演技術(shù),主要探討單頻濃度反演中的衰減修正問(wèn)題、雙頻濃度反演方法以及多頻的粒徑反演方法(能量比算法、差值算法和最近鄰算法)。論文同時(shí)從多參數(shù)優(yōu)化的角度出發(fā),探討粒子群優(yōu)化算法(Particle Swarm Optimization,簡(jiǎn)稱PSO)在懸浮顆粒反演方面的應(yīng)用。通過(guò)對(duì)仿真數(shù)據(jù)進(jìn)行反演分析,探討300kHz單頻濃度反演算法,200、300、500kHz多頻率粒徑和濃度反演算法的性能。 最后介紹一種專用水體特性剖面測(cè)量系統(tǒng)的實(shí)現(xiàn)方案,包括系統(tǒng)整體架構(gòu)、電子硬件模塊設(shè)計(jì)、軟件設(shè)計(jì)等。通過(guò)利用寬帶ADCP與研制的試驗(yàn)系統(tǒng)進(jìn)行多次的實(shí)際海洋環(huán)境數(shù)據(jù)采集,并對(duì)采集數(shù)據(jù)應(yīng)用論文所研究的算法進(jìn)行處理分析,驗(yàn)證了系統(tǒng)方案與算法實(shí)現(xiàn)的有效性。
[Abstract]:The measurement of suspended particles in water based on acoustics is an important means to study the characteristics of suspended sediment concentration distribution and transport in water, compared with the traditional suspended particle observation technology. Acoustic-based method is a non-interference profile measurement method, which is easy to operate and has a high space-time resolution. In recent years, more and more attention has been paid to the measurement data. However, the acoustic signal processing technology involved is relatively complex. This paper focuses on the application of acoustic backscattering technology in the measurement of suspended particle concentration profile. The aim of this paper is to explore an effective method for acoustic inversion of suspended particle concentration. The basic principle of acoustic backscatter measurement method is that transmitting transducer emits short-time acoustic pulse signal to water body and scattering sound energy of suspended matter in water body. Receiving the transducer to record the echo signal propagating in the opposite direction of the transmission; Echo signals carry the physical characteristics of suspended matter, and the relevant physical parameters can be obtained by acoustic inversion. In the acoustic measurement process, special consideration should be given to the attenuation of acoustic waves caused by suspended particles themselves. The joint contribution of suspended particle size and concentration to scattering sound energy is also discussed. According to the attenuation characteristics of acoustic scattering, the geometric spread attenuation and absorption attenuation are introduced in this paper. The scattering characteristics of suspended particles are discussed from two directions: the effective acoustic cross section area and the scattering form function. Firstly, the paper takes the broadband acoustic Doppler velocity profiler (ADCP) as an example. In this paper, a method of constructing the scattering echo of wide band water body is introduced, that is, the energy change of the acoustic wave propagation process is analyzed by analyzing the emission signal in the process of broadband ADCP measurement. Each frequency component is processed separately in frequency domain. Finally, the inverse scattering echo of reconstructed water is synthesized by Fourier transform. The simulation results show that the backscattering echo constructed by this method is in good agreement with the measured environmental signal at the angle of statistical significance. In this paper, the inversion method of suspended particle concentration and particle size based on acoustic backscattering is studied, and it is divided into single frequency and multi-frequency inversion technology according to the use of measurement frequency. This paper mainly discusses the problem of attenuation correction in single-frequency concentration inversion, dual-frequency concentration inversion method and multi-frequency particle size inversion method (energy ratio algorithm). The difference algorithm and the nearest neighbor algorithm are discussed in this paper. At the same time, from the point of view of multi-parameter optimization, particle swarm optimization (PSO) algorithm is discussed. The application of PSOs in the inversion of suspended particles is discussed. The inversion algorithm of 300kHz single frequency concentration is discussed through the inversion analysis of the simulation data. Performance of 500 kHz multi-frequency particle size and concentration inversion algorithm. Finally, a special water profile measurement system is introduced, including the whole structure of the system and the design of electronic hardware module. Software design. Through the use of broadband ADCP and the developed experimental system for the actual marine environment data acquisition, and the collection of data application of the algorithm studied in the paper for processing and analysis. The validity of the scheme and algorithm is verified.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P715

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 高建華,汪亞平,王愛(ài)軍,李占海,楊e，

本文編號(hào)：1450230