多途混响环境中声扩频信号线性与相关性分析
2024,46(4):191-200
唐永壮
海军工程大学 舰船与海洋学院, 湖北 武汉 430033，tang_yongzhuang@126.com
周其斗
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
谢志勇
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
吕晓军
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
纪刚
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
海军工程大学 舰船与海洋学院, 湖北 武汉 430033，tang_yongzhuang@126.com
周其斗
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
谢志勇
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
吕晓军
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
纪刚
海军工程大学 舰船与海洋学院, 湖北 武汉 430033
摘要：
为分析浅海多途信道中声扩频信号的相关性和线性,建立了计入频率衰减与海底损耗的浅海Pekeris波导虚源法计算模型；对浅海中的脉冲信号与扩频信号进行了仿真计算,通过混响室试验初步研究了多途混响环境中扩频信号的线性。仿真结果显示:虚源法和简正波法的频域解一致,得到了与简正波理论相同的低频模式频散现象,验证了虚源法适用于浅海理想波导、Pekeris波导中的低频问题；当发生模式频散,低频扩频信号的相关性能强于同扩频参数的高频信号。试验结果表明:低频脉冲的时域波形发生畸变、展宽时,同频率的扩频信号能准确测出反射信号的几何时延,证明了低频多途效果仍可看作每个“路径”信号的线性叠加。
为分析浅海多途信道中声扩频信号的相关性和线性,建立了计入频率衰减与海底损耗的浅海Pekeris波导虚源法计算模型；对浅海中的脉冲信号与扩频信号进行了仿真计算,通过混响室试验初步研究了多途混响环境中扩频信号的线性。仿真结果显示:虚源法和简正波法的频域解一致,得到了与简正波理论相同的低频模式频散现象,验证了虚源法适用于浅海理想波导、Pekeris波导中的低频问题；当发生模式频散,低频扩频信号的相关性能强于同扩频参数的高频信号。试验结果表明:低频脉冲的时域波形发生畸变、展宽时,同频率的扩频信号能准确测出反射信号的几何时延,证明了低频多途效果仍可看作每个“路径”信号的线性叠加。
基金项目：
国家自然科学基金资助项目(52071334)
国家自然科学基金资助项目(52071334)
Analysis of linearity and correlation of acoustic spread spectrum signal in multipath reverberation channel
TANG Yongzhuang
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China,tang_yongzhuang@126.com
ZHOU Qidou
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
XIE Zhiyong
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
LYU Xiaojun
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
JI Gang
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China,tang_yongzhuang@126.com
ZHOU Qidou
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
XIE Zhiyong
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
LYU Xiaojun
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
JI Gang
College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
Abstract：
To analyze the correlation and linearity of acoustic spread spectrum signals in shallow water multipath channels, a virtual source calculation model for Pekeris waveguides in shallow waters with frequency attenuation and seabed loss was established. Pulse signals and spread spectrum signals in shallow seas were simulated, and the linearity of spread spectrum signals in a multipath reverberation environment was preliminarily investigated through experiments conducted in a reverberation chamber. Simulation results show that the frequency domain solution of the virtual source method is consistent with that of the normal mode method, and the same low-frequency mode dispersion phenomenon as the normal mode method can be obtained through the virtual source method, verifying that the virtual source method is suitable for low-frequency problems in ideal shallow water waveguides and Pekeris waveguides; when modal dispersion occurs, the correlation performance of low-frequency spread spectrum signals is better than that of high-frequency signals under the same conditions. Experimental results show that when the time-domain waveform of a low-frequency pulse is distorted and broadened, the spread spectrum signal of the same frequency can accurately measure the geometric delay of the reflected signal, demonstrating that the low-frequency multipath effect can still be regarded as the linear superposition of all "path" signals.
To analyze the correlation and linearity of acoustic spread spectrum signals in shallow water multipath channels, a virtual source calculation model for Pekeris waveguides in shallow waters with frequency attenuation and seabed loss was established. Pulse signals and spread spectrum signals in shallow seas were simulated, and the linearity of spread spectrum signals in a multipath reverberation environment was preliminarily investigated through experiments conducted in a reverberation chamber. Simulation results show that the frequency domain solution of the virtual source method is consistent with that of the normal mode method, and the same low-frequency mode dispersion phenomenon as the normal mode method can be obtained through the virtual source method, verifying that the virtual source method is suitable for low-frequency problems in ideal shallow water waveguides and Pekeris waveguides; when modal dispersion occurs, the correlation performance of low-frequency spread spectrum signals is better than that of high-frequency signals under the same conditions. Experimental results show that when the time-domain waveform of a low-frequency pulse is distorted and broadened, the spread spectrum signal of the same frequency can accurately measure the geometric delay of the reflected signal, demonstrating that the low-frequency multipath effect can still be regarded as the linear superposition of all "path" signals.
收稿日期：
2023-05-16
2023-05-16
