大型储罐水声信道建模及通信方案研究

发布时间：2019-03-21 09:58

【摘要】：我国是一个能源大国,随着国民经济的迅速发展,我国对石油的需求量与日俱增。大型石油储罐作为油品存储的重要设施,在数量迅速增长的同时其安全也受到广泛的关注。石油储罐一旦发生事故,将造成巨大的经济损失,甚至威胁生命、财产安全,影响巨大。本文以基于游弋式无线传感节点的石油储罐罐底腐蚀在线检测系统的应用为背景,研究储罐封闭空间内的水声通信技术及实现方案,主要工作包括以下几个方面:(1)建立了储罐水声信道模型,明确了不同形状、不同尺寸封闭空间水声信道的冲激响应,讨论了储罐空间内多径信号的特点,并与海洋中的多径效应进行了对比与分析,为构造适合储罐内应用的水声通信方案提供了理论依据。(2)针对储罐内水声信道的特点以及对水声通信的要求,提出了直接序列扩频OFDM通信方案,并分析了扩频OFDM通信方案的抗多径性能,讨论了扩频OFDM的信道编码方案。计算机仿真和试验数据表明,扩频OFDM技术相比传统OFDM方法在储罐空间内拥有更可靠的传输性能。(3)游弋式传感节点在检测过程中需要将采集到的腐蚀声发射数据回传到中央控制站,这一过程需要尽可能高的传输速率。扩频OFDM系统方案的扩频过程造成了频谱资源的浪费。论文结合储罐腐蚀声发射检测应用中扩频序列较短的特点,提出了映射序列扩频OFDM的方法。仿真和试验证明了映射序列扩频OFDM方案比直接序列扩频OFDM方案传输效率提高了两倍。(4)分析了多普勒频移对储罐内扩频OFDM水声通信系统的影响,提出了基于最大相关峰偏移的多普勒因子估计方法,采用两步补偿法对多普勒频移进行补偿,计算简单、运算量小,能满足实时处理的需要。试验证明利用本文的估计与补偿方法,能够有效消除游弋式传感节点移动中的多普勒频移对通信的影响。
[Abstract]:China is an energy power, with the rapid development of the national economy, our country's demand for oil is increasing. As an important facility for oil storage, large-scale oil storage tanks are of great concern at the same time of rapid growth. In the event of an accident, the oil storage tank will cause great economic loss and even threaten the life, property safety and great influence. In this paper, based on the application of the on-line detection system of the tank bottom of the oil storage tank based on the wandering type wireless sensor node, the underwater acoustic communication technology and the implementation scheme in the closed space of the storage tank are studied. The main work includes the following aspects: (1) the underwater acoustic channel model of the storage tank is established, The impulse response of the underwater acoustic channel with different shapes and different sizes is defined, the characteristics of multi-path signals in the tank space are discussed, and the multi-path effect in the ocean is compared and analyzed, which provides a theoretical basis for constructing the underwater acoustic communication scheme suitable for the application in the storage tank. (2) In view of the characteristics of the underwater acoustic channel in the storage tank and the requirements of the underwater acoustic communication, the direct sequence spread spectrum OFDM communication scheme is proposed, and the anti-multipath performance of the spread spectrum OFDM communication scheme is analyzed, and the channel coding scheme of the spread spectrum OFDM is discussed. The computer simulation and the test data show that the spread spectrum OFDM has more reliable transmission performance in the tank space than the traditional OFDM method. (3) The mobile sensing node needs to transmit the collected corrosion acoustic emission data back to the central control station during the detection process, which requires as high a transmission rate as possible. The spreading process of the spread spectrum ofdm system scheme results in a waste of spectrum resources. In this paper, based on the characteristics of the short-spectrum sequence in the detection and application of the corrosion-acoustic emission of the storage tank, a method for spreading the OFDM by using the mapping sequence is proposed. The simulation and test prove that the transmission efficiency of the mapping sequence spread spectrum OFDM scheme is more than twice the transmission efficiency of the direct sequence spread spectrum OFDM scheme. (4) The influence of the Doppler frequency shift on the spread spectrum OFDM underwater acoustic communication system in the storage tank is analyzed, and the Doppler factor estimation method based on the maximum correlation peak shift is proposed. The two-step compensation method is adopted to compensate the Doppler frequency shift, and the calculation is simple, the calculation amount is small, and the need of real-time processing can be met. The experimental results show that the influence of Doppler shift on communication can be effectively eliminated by using the estimation and compensation method of this paper.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TE973

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