基于空间—波数滤波器的水声信号预处理算法研究

发布时间：2018-08-16 16:15

【摘要】：在水声通信系统中,水下环境极为复杂,信号在传输过程中,受到多径效应和多个水声发射换能器同时发送信号的干扰,造成信号的混叠,降低了通信可靠性和定位精度,使用编码、信道均衡等方法也不能达到很好的效果。针对该问题,本课题提出了一种基于空间-波数滤波器的水声信号预处理方法。本文在分析研究空间-波数滤波算法的基础上,针对水声信号特征,通过计算机仿真验证了算法的可行性,并对水声接收换能器阵列实际采集的水声信号做了滤波处理,在通信的可靠性和定位精度两个方面都有所提高。在此基础上,对空间-波数滤波器的滤波特性、远近场和角度盲区特性进行了分析。针对基于空间-波数滤波器的水声信号预处理算法的滤波特性,提出了窗函数法优化的空间-波数滤波器,使空间-波数滤波器的旁瓣得到抑制;针对空间-波数滤波器的近场盲区和角度盲区问题,提出了基于近场优化和十字阵的全方位水声信号处理方法;针对空间-波数滤波器需要预先知道水声信号的波数和角度的先验知识,但实际水下环境极为恶劣,很难获得先验知识的问题,提出了一种结合窗函数和全方位的自适应空间-波数滤波器的水声信号预处理方法。通过使用三种优化方法分别对实际采集的水声信号进行处理后,仿真结果显示,经过优化后空间-波数滤波后信号的误码率和定位误差均有所降低。自适应空间-波数滤波器水声信号的波数和角度未知的情况下,依然可以抑制水声信号的多径干扰和实现多个水声信号的分离,提高通信可靠性和定位精度。因此,自适应空间-波数滤波器是本文的最优算法。
[Abstract]:In underwater acoustic communication system, the underwater environment is very complex. During the process of transmission, the signal is interfered by multi-path effect and multiple underwater acoustic emission transducers at the same time, which results in the overlapping of signals and reduces the communication reliability and positioning accuracy. The use of coding, channel equalization and other methods can not achieve good results. In order to solve this problem, a preprocessing method of underwater acoustic signal based on space-wave filter is proposed. Based on the analysis and study of the space-wave-number filtering algorithm, the feasibility of the algorithm is verified by computer simulation aiming at the characteristics of underwater acoustic signals, and the underwater acoustic signals collected by underwater acoustic receiving transducer array are filtered. Both the reliability and positioning accuracy of communication are improved. On this basis, the filtering characteristics, far and near field and angle blind area characteristics of space-wavenumber filter are analyzed. According to the filtering characteristics of the spatial wave number filter based on underwater acoustic signal preprocessing algorithm, the spatial wave number filter is optimized by window function method, which can suppress the sidelobe of the space wave number filter. Aiming at the problem of near-field blind area and angle blind area of space-wavenumber filter, an omnidirectional underwater acoustic signal processing method based on near-field optimization and cross array is proposed. A prior knowledge of wave number and angle of underwater acoustic signal is needed in advance for space-wavenumber filter, but the actual underwater environment is very bad, so it is difficult to obtain prior knowledge. In this paper, a preprocessing method for underwater acoustic signal is proposed, which combines window function with an omnidirectional adaptive space-wave-number filter. The simulation results show that the bit error rate and positioning error of the signal are reduced after the optimized space-wave-number filtering. When the wave number and angle of underwater acoustic signal of adaptive space-wave-number filter are unknown, the multi-path interference of underwater acoustic signal can still be suppressed and the separation of multiple underwater acoustic signals can be realized, and the communication reliability and positioning accuracy can be improved. Therefore, adaptive space-wavenumber filter is the optimal algorithm in this paper.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713;TN929.3

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