In this paper, the phase characteristic disturbance model for baseband direct sequence spread spectrum (DSSS) signal in additive white Gaussian noise (AWGN) environment is established, and the probability density func...In this paper, the phase characteristic disturbance model for baseband direct sequence spread spectrum (DSSS) signal in additive white Gaussian noise (AWGN) environment is established, and the probability density function (PDF) of phase characteristic disturbance is obtained. Then a novel receiver model for baseband DSSS signal based on maximum likelihood (ML) criterion is proposed. The simulation results show that, comparing with correlation scheme, the performance of the proposed method for baseband DSSS signal is 1dB worse in AWGN environment. However, if there is narrow interference in the AWGN environment, the proposed method will show better performance up to 2.5dB, and it has good adaptive resistance to narrowband interference located in different frequency points. This method could be used as an alterative communication scheme for military circumstance when existing strong narrowband interference of various frequencies.展开更多
间歇采样噪声调制转发式的灵巧噪声干扰向来是雷达干扰对抗的难点。在深入研究间歇采样转发干扰(interrupted-sampling repeater jamming,ISRJ)的基础上,针对ISRJ时域不连续采样的特点,提出一种基于脉内步进线性调频(linear frequency m...间歇采样噪声调制转发式的灵巧噪声干扰向来是雷达干扰对抗的难点。在深入研究间歇采样转发干扰(interrupted-sampling repeater jamming,ISRJ)的基础上,针对ISRJ时域不连续采样的特点,提出一种基于脉内步进线性调频(linear frequency modulation,LFM)波形的抗ISRJ方法。该方法利用脉内步进LFM子脉冲之间的正交性互相掩护,子脉冲间频率步进使得干扰采样段经调制后仍无法干扰相邻子脉冲,从而可以有效提取干扰机没有采样的信号段,在对抗高占空比的重复转发干扰时优势明显。仿真条件下,干扰采样与发射波形分段非同步时,窄子脉冲较宽子脉冲输出信干噪比提高约3.1dB。展开更多
针对传统硬件电路存在的设备研发周期长、开发成本高的问题,文中基于软件无线电架构设计了可配置、可重构、可扩展的地面终端系统,并在此基础上开展了抗干扰技术研究。通过设计快速跳变窄带滤波器,采用跳频、扩频相结合的混合抗干扰措施...针对传统硬件电路存在的设备研发周期长、开发成本高的问题,文中基于软件无线电架构设计了可配置、可重构、可扩展的地面终端系统,并在此基础上开展了抗干扰技术研究。通过设计快速跳变窄带滤波器,采用跳频、扩频相结合的混合抗干扰措施,使得该地面终端可有效对抗地面环境存在的多径干扰、阻塞式及跟踪式干扰。在实验室搭建的抗干扰测试环境,验证了该终端在跳频模式下抗干扰容限优于20 d B,能够满足其性能指标要求。展开更多
介绍了短波宽带正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)通信系统的特性,阐述了OFDM系统对短波通信过程中窄带干扰的影响,分析了不同算法窄带干扰抑制的效果。总结窄带干扰抑制的手段并结合短波通信的特点,提出...介绍了短波宽带正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)通信系统的特性,阐述了OFDM系统对短波通信过程中窄带干扰的影响,分析了不同算法窄带干扰抑制的效果。总结窄带干扰抑制的手段并结合短波通信的特点,提出了一种有效的抗干扰措施和干扰抑制算法,通过准确计算干扰信号的中心频点,借助建立的多级陷波器移除干扰电台信号达到抗干扰的效果,对短波通信抗干扰技术的进步具有积极的意义。展开更多
基金supported by the National Basic Research Program (973 Program) of China under Grant No.2007CB310606National Key Technologies R&D Program under Grant No.2009ZX03004-001
文摘In this paper, the phase characteristic disturbance model for baseband direct sequence spread spectrum (DSSS) signal in additive white Gaussian noise (AWGN) environment is established, and the probability density function (PDF) of phase characteristic disturbance is obtained. Then a novel receiver model for baseband DSSS signal based on maximum likelihood (ML) criterion is proposed. The simulation results show that, comparing with correlation scheme, the performance of the proposed method for baseband DSSS signal is 1dB worse in AWGN environment. However, if there is narrow interference in the AWGN environment, the proposed method will show better performance up to 2.5dB, and it has good adaptive resistance to narrowband interference located in different frequency points. This method could be used as an alterative communication scheme for military circumstance when existing strong narrowband interference of various frequencies.
文摘间歇采样噪声调制转发式的灵巧噪声干扰向来是雷达干扰对抗的难点。在深入研究间歇采样转发干扰(interrupted-sampling repeater jamming,ISRJ)的基础上,针对ISRJ时域不连续采样的特点,提出一种基于脉内步进线性调频(linear frequency modulation,LFM)波形的抗ISRJ方法。该方法利用脉内步进LFM子脉冲之间的正交性互相掩护,子脉冲间频率步进使得干扰采样段经调制后仍无法干扰相邻子脉冲,从而可以有效提取干扰机没有采样的信号段,在对抗高占空比的重复转发干扰时优势明显。仿真条件下,干扰采样与发射波形分段非同步时,窄子脉冲较宽子脉冲输出信干噪比提高约3.1dB。
文摘针对传统硬件电路存在的设备研发周期长、开发成本高的问题,文中基于软件无线电架构设计了可配置、可重构、可扩展的地面终端系统,并在此基础上开展了抗干扰技术研究。通过设计快速跳变窄带滤波器,采用跳频、扩频相结合的混合抗干扰措施,使得该地面终端可有效对抗地面环境存在的多径干扰、阻塞式及跟踪式干扰。在实验室搭建的抗干扰测试环境,验证了该终端在跳频模式下抗干扰容限优于20 d B,能够满足其性能指标要求。
文摘介绍了短波宽带正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)通信系统的特性,阐述了OFDM系统对短波通信过程中窄带干扰的影响,分析了不同算法窄带干扰抑制的效果。总结窄带干扰抑制的手段并结合短波通信的特点,提出了一种有效的抗干扰措施和干扰抑制算法,通过准确计算干扰信号的中心频点,借助建立的多级陷波器移除干扰电台信号达到抗干扰的效果,对短波通信抗干扰技术的进步具有积极的意义。
