The paper analyses the characteristics of radio frequency interference （RFI） in HF surface wave radar （HFSWR） which adopts the linear frequency modulated interrupted continuous wave （FMICW）. RFI will influence a...The paper analyses the characteristics of radio frequency interference （RFI） in HF surface wave radar （HFSWR） which adopts the linear frequency modulated interrupted continuous wave （FMICW）. RFI will influence all the range cells including all the positive frequency and negative frequency, and the negative frequency range cells contain only the interference information. Based on the above characteristics, we introduce and analyze a new adaptive interference mitigation beamforming algorithm using the negative frequency range cells samples to estimate the interference covariance matrix. Experimental results confirm that this general and robust algorithm can achieve effective RFI suppression using the data recorded by the HFSWR, located near Zhoushan in Zhejiang China.展开更多
Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly p...Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.展开更多
本文研究了一种新的高频地波超视距雷达目标距离以及方位角超分辨问题.在该雷达系统中,各个发射阵元采用不同的发射载频,因此目标回波信号中存在目标距离与方位角的耦合,本文提出利用这种耦合关系,采用M U S IC(M u ltip le S igna l C ...本文研究了一种新的高频地波超视距雷达目标距离以及方位角超分辨问题.在该雷达系统中,各个发射阵元采用不同的发射载频,因此目标回波信号中存在目标距离与方位角的耦合,本文提出利用这种耦合关系,采用M U S IC(M u ltip le S igna l C lassifica tion)算法获得目标距离以及方位角的超分辩,从而提高在多目标环境下测距、测角精度.仿真结果验证了该方法的有效性.展开更多
文摘The paper analyses the characteristics of radio frequency interference （RFI） in HF surface wave radar （HFSWR） which adopts the linear frequency modulated interrupted continuous wave （FMICW）. RFI will influence all the range cells including all the positive frequency and negative frequency, and the negative frequency range cells contain only the interference information. Based on the above characteristics, we introduce and analyze a new adaptive interference mitigation beamforming algorithm using the negative frequency range cells samples to estimate the interference covariance matrix. Experimental results confirm that this general and robust algorithm can achieve effective RFI suppression using the data recorded by the HFSWR, located near Zhoushan in Zhejiang China.
文摘Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.
文摘本文研究了一种新的高频地波超视距雷达目标距离以及方位角超分辨问题.在该雷达系统中,各个发射阵元采用不同的发射载频,因此目标回波信号中存在目标距离与方位角的耦合,本文提出利用这种耦合关系,采用M U S IC(M u ltip le S igna l C lassifica tion)算法获得目标距离以及方位角的超分辩,从而提高在多目标环境下测距、测角精度.仿真结果验证了该方法的有效性.
