提出了一种测量长光纤微波光链路以及链路中某一器件残余相位噪声的方法。与以前传统的残余相位噪声测量方法相比,新提出的基于互相关的双音法抑制了不相关噪声源引入的噪声,而保留了待测器件的噪声。通过这种方法,测量了外调制长光纤...提出了一种测量长光纤微波光链路以及链路中某一器件残余相位噪声的方法。与以前传统的残余相位噪声测量方法相比,新提出的基于互相关的双音法抑制了不相关噪声源引入的噪声,而保留了待测器件的噪声。通过这种方法,测量了外调制长光纤微波光链路的残余相位噪声,一个6 km微波光纤链路的残余相位噪声在1 k Hz频偏处被测得为-130 d Bc/Hz,在10 k Hz频偏处被测得为-140 d Bc/Hz,相较于光纤长度为1 m的短微波光链路,残余相位噪声恶化了接近10 d B。另外,为了找出光电探测器的残余相位噪声与其非线性引起的射频功率压缩度之间的关系,还用这种方法测量了工作在不同条件下的光电探测器的残余相位噪声,实验结果表明:光电探测器的非线性会恶化它的残余相位噪声。展开更多
Two approximations, center-beam approximation and reference digital elevation model （DEM） approximation, are used in synthetic aperture radar （SAR） motion compensation procedures. They usually introduce residual m...Two approximations, center-beam approximation and reference digital elevation model （DEM） approximation, are used in synthetic aperture radar （SAR） motion compensation procedures. They usually introduce residual motion compensation errors for airborne single-antenna SAR imaging and SAR interferometry. In this paper, we investigate the effects of residual uncompensated motion errors, which are caused by the above two approximations, on the performance of airborne along-track interferometric SAR （ATI-SAR）. The residual uncompensated errors caused by center-beam approximation in the absence and in the presence of elevation errors are derived, respectively. Airborne simulation parameters are used to verify the correctness of the analysis and to show the impacts of residual uncompensated errors on the interferometric phase errors for ATI-SAR. It is shown that the interferometric phase errors caused by the center-beam approximation with an accurate DEM could be neglected, while the interferometric phase errors caused by the center-beam approximation with an inaccurate DEM cannot be neglected when the elevation errors exceed a threshold. This research provides theoretical bases for the error source analysis and signal processing of airborne ATI-SAR.展开更多
文摘提出了一种测量长光纤微波光链路以及链路中某一器件残余相位噪声的方法。与以前传统的残余相位噪声测量方法相比,新提出的基于互相关的双音法抑制了不相关噪声源引入的噪声,而保留了待测器件的噪声。通过这种方法,测量了外调制长光纤微波光链路的残余相位噪声,一个6 km微波光纤链路的残余相位噪声在1 k Hz频偏处被测得为-130 d Bc/Hz,在10 k Hz频偏处被测得为-140 d Bc/Hz,相较于光纤长度为1 m的短微波光链路,残余相位噪声恶化了接近10 d B。另外,为了找出光电探测器的残余相位噪声与其非线性引起的射频功率压缩度之间的关系,还用这种方法测量了工作在不同条件下的光电探测器的残余相位噪声,实验结果表明:光电探测器的非线性会恶化它的残余相位噪声。
基金Project supported by the National Natural Science Foundation of China （Nos. 61331017 and 61401428）
文摘Two approximations, center-beam approximation and reference digital elevation model （DEM） approximation, are used in synthetic aperture radar （SAR） motion compensation procedures. They usually introduce residual motion compensation errors for airborne single-antenna SAR imaging and SAR interferometry. In this paper, we investigate the effects of residual uncompensated motion errors, which are caused by the above two approximations, on the performance of airborne along-track interferometric SAR （ATI-SAR）. The residual uncompensated errors caused by center-beam approximation in the absence and in the presence of elevation errors are derived, respectively. Airborne simulation parameters are used to verify the correctness of the analysis and to show the impacts of residual uncompensated errors on the interferometric phase errors for ATI-SAR. It is shown that the interferometric phase errors caused by the center-beam approximation with an accurate DEM could be neglected, while the interferometric phase errors caused by the center-beam approximation with an inaccurate DEM cannot be neglected when the elevation errors exceed a threshold. This research provides theoretical bases for the error source analysis and signal processing of airborne ATI-SAR.
