A Method for Extending Doppler Tolerance of Underwater Spread Spectrum Signal
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摘要: 扩频信号的模糊函数图呈图钉型, 对多普勒频移比较敏感, 影响了扩频信号的使用性能。本文分析了扩频信号的多普勒敏感性问题, 提出了一种基于回波预处理的方法。首先将回波信号经过正交混频得到零中频I, Q通道信号, 然后将零中频I, Q通道信号送入多普勒预处理系统进行处理, 通过时间延迟处理方法得到的2个输出信号, 分别经过匹配滤波器后再进行合并处理, 脉压输出相关函数中不含多普勒频移和时间乘积, 消除了多普勒频移对匹配滤波器输出的影响。数值仿真证明了该方法的有效性, 且具有实现简单, 运算量小的优点。Abstract: Spread spectrum signal is sensitive to Doppler frequency shift, which limits the service property of the spread spectrum signal. This paper proposes a method for echo pre-processing by analyzing the sensitivity of spread spectrum signal to Doppler frequency shift. Zero intermediate frequency I, Q channel signals are obtained through the orthogonal frequency mixing of echo. Then the signals are processed in the echo pre-processing system to obtain two output signals by time-delay processing method. The two output signals are further processed by a matching filter to achieve a combined signal which doesn’t contain Doppler frequency shift and time product. Numerical simulation demonstrates the validity of the proposed method with simplicity and smaller amount of computation.
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[1] 田黎育, 高梅国. 一种二相编码信号多普勒补偿方法的研究与实现[J]. 北京理工大学学报, 2002, 22(6): 757-760. [2] 孙东延, 陶建锋, 付全喜. 相位编码信号的多普勒补偿[J].空军工程大学学报(自然科学版), 2000, 1(1): 47-49. [3] 贾鸿志, 朱晓华, 胡庆武, 等. 用补偿式旁瓣抑制滤波器扩展二相码信号的多普勒容限[J]. 信号处理, 1994, 10(3): 187-192. [4] Park S C, Doherty John F. A Minimax Optimization Ap-proach to Sidelobe Suppression Filter Design[C]//IEEE National Radar Conference, 1996: 3113-3116. [5] Nathanson F E, Patrick R, Cohen M N, et al. Radar Design Principle-signal Processing and the Environment[C]//IEEE National Radar Conference, 1991: 515-519.
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