【作者】 陈平；

【导师】 张旨遥；

【作者基本信息】 电子科技大学 ， 光学工程， 2025， 硕士

【摘要】 分布式相参孔径雷达(Distributed Coherent Aperture Radar,DCAR)是由多个空间分离的天线孔径组成的雷达系统,通过对多个孔径雷达进行信号相干合成,可获得等效大孔径雷达的性能,在深空遥感探测、超远距离雷达探测、射电天文等诸多领域具有广阔的应用前景。传统DCAR系统中的中心站与雷达单元之间的信号依靠电缆传输,传输损耗较大且易受电磁环境影响,使得各孔径雷达间存在严重的时间与相位同步误差。为突破电学局限,光载射频(Radio-over-Fiber,RoF)链路凭借其传输损耗低、大带宽、抗电磁干扰强等优势成为了新的选择,但在传输过程中,链路噪声及光纤非线性效应对于传输信号质量提出了新的挑战。基于此,本文主要对基于RoF链路的雷达信号传递进行研究,通过理论及实验手段对链路噪声、色散、光纤非线性效应等多种影响因素进行分析,以提升终端信号质量。论文的主要研究内容如下:1.提出了一种基于高功率RoF链路的时钟信号传递方案。针对时钟信号传递过程中链路增益不足问题,通过应用高功率RoF链路实现了时钟信号的高质量、远距离稳定传输。实验探究了传统RoF链路与高功率RoF链路中在不同传输距离下的时钟信号相位噪声特性,结果表明,高功率RoF链路在应用相位调制方案有效缓解受激布里渊散射(Stimulated Brillouin Scattering,SBS)效应后,可以进一步降低传输信号相位噪声,提高时钟信号传输质量。2.提出了一种基于低偏置技术与相位调制结合的高功率高频本振信号传递方案。针对传输链路噪声较大的问题,首先在链路增益一致的前提下,通过实验对比研究了两链路的模拟特性,验证了高功率RoF链路的低噪声系数与高链路线性度特性。然后在高功率RoF链路基础上,通过低偏置技术与相位调制相结合的技术手段,实现了链路噪声系数的进一步改善,结果表明,在20 km光纤传输场景下,链路噪声系数在10 GHz处可以被降低7.02 d B。3.验证了一种基于相位调制与色散管理的高功率宽带雷达信号传递方案。针对SBS效应与色散所带来的幅度与相位畸变问题,通过相位调制与色散管理结合的手段,实现了线性调频(Linear Frequency Modulation,LFM)信号的高质量传输。实验验证了SBS效应与色散的缓解,对于链路输出LFM信号质量具有明显优化。更多还原

【Abstract】 Distributed coherent aperture radar(DCAR)is a radar system composed of multiple spatially separated antenna apertures.By coherently synthesizing signals from multiple aperture radars,it can achieve the performance of an equivalent large-aperture radar,which has broad application prospects in missile defense,deep space remote sensing,ultra-long-range radar detection,radio astronomy,and many other fields.Traditional DCAR systems suffer from significant transmission loss and are easily affected by the electromagnetic environment,since the signals between the central station and the unit radars are transmitted via cables,which leads to serious time and phase synchronization errors among the aperture radars.To overcome these electrical limitations,radio-over-fiber(RoF)links with inherent advantages of low transmission loss,large bandwidth and immunity of electromagnetic interference,have become a new choice for DCAR connection.However,new challenges such as link noise and fiber nonlinear effects have emerged.Therefore,this thesis intends to investigate the transmission of radar frequency signals based on RoF links,aiming to analyze various influencing factors including link noise,dispersion and fiber nonlinear effects to improve the signal quality at the receiving end.The main research works of the thesis are listed as follows.1.A clock signal transmission scheme based on high-power RoF link is proposed.In order to solve the problem of insufficient link gain in the process of clock signal transmission,the high-quality and long-distance stable transmission of clock signals is realized by applying a high-power RoF link.The experimental results show that the phase noise of the transmitted signal can be further reduced and the transmission quality of the clock signal can be improved,where a phase modulation scheme is used to reduce the stimulated Brillouin scattering(SBS)effect.2.A high-power high-frequency local oscillator signal transmission scheme based on the combination of low biased intensity modulation and phase modulation is proposed.In order to solve the problem of high noise in the transmission link,firstly,under the premise that the link gain is consistent,the analog characteristics of the two links are compared and studied through experiments,and the characteristics of low noise figure and high link dynamic of the high-power RoF link are verified.Then,on the basis of the high-power RoF link,the link noise figure is further improved by combining the low bias technology and phase modulation,where the results show that the link noise figure can be reduced by 7.02 d B at 10 GHz in the 20 km fiber transmission scenario.3.A high-power wideband radar signal transmission scheme based on phase modulation and dispersion management is verified.In order to solve the amplitude and phase distortion caused by SBS effect and dispersion,a high-quality transmission link of linear frequency modulation(LFM)signals is realized by combining phase modulation and dispersion management.Experiment results verify that the SBS effect and dispersion are reduced,and the quality of the LFM signal output of the link is significantly optimized.更多还原