The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circu...The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circular SAR （CSAR） imaging geometry, the system response function is in the form of the Bessel function which brings a high sidelobe, and the high sidelobe of CSAR will be an important factor influencing the interferometric coherence. The effect of the high sidelobe on the coherence is analyzed and deduced. Based on the interferometric characteristics of the slight difference in the viewing angles and the potential pixel off- set in the interferometric SAR （InSAR） images, a relation between the radar impulse response and the coherence loss function is derived. From the relational model, the coherence loss function due to the high sidelobe of CSAR is then deduced, and compared with that of the conventional SAR. It is shown that the high sidelobe of CSAR focusing signal will severely affect the baseline decorre- lation and coregistration decorrelation. Simulation results confirm the theoretical analysis and quantitatively show the baseline and coregistration decorrelation degradation due to the high sidelobes of CSAR.展开更多
Airborne Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) baseline error is a main error resource affecting the precision of velocity measurement of moving objects and therefore should be calibrated exte...Airborne Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) baseline error is a main error resource affecting the precision of velocity measurement of moving objects and therefore should be calibrated externally. The Jet Propulsion Laboratory (JPL) has proposed a calibration scheme for tasks of PacRim98 and PacRim2000 based on several static objects on the ground. In this paper, the influence of phase center uncertainty on baseline determination by using PacRim method proposed by JPL is analyzed. According to the analysis, the phase center uncertainty can cause a constant part of error to the result of baseline calibration. In order to deal with this problem, an improved calibration method on the basis of sensitivity equations and some ground moving targets, whose velocities are already known, is proposed in this paper. The simulation results show that our proposed calibration method has improved the accuracy of baseline calibration and has obviously prohibited the effect of antennas' phase center uncertainty.展开更多
基于干涉合成孔径雷达(Interferometric SAR,InSAR)技术生成高精度数字高程模型(Digital ElevationModel,DEM),需要进行干涉定标。繁重的地面控制点(Ground Control Points,GCPs)布放不利于InSAR大区域地形测绘的自动化。该文介绍一种稀...基于干涉合成孔径雷达(Interferometric SAR,InSAR)技术生成高精度数字高程模型(Digital ElevationModel,DEM),需要进行干涉定标。繁重的地面控制点(Ground Control Points,GCPs)布放不利于InSAR大区域地形测绘的自动化。该文介绍一种稀疏GCPs下,基于自动提取的连接点(Tie Points,TPs),利用最小二乘平差原理,实现InSAR区域网内多景相互重叠DEM的同时重建方法。通过改变参与重建的TPs数目,用X波段InSAR实测数据的实验验证了该文方法的有效性。展开更多
工作在低频段的SAR容易受到射频干扰(Radio Frequency Interference,RFI)的影响,而导致SAR图像质量的恶化。对于重复轨道InSAR来说,RFI的存在还会影响其干涉相位。针对此问题,该文将实测RFI信号加入仿真的典型圆锥场景回波,进行成像和...工作在低频段的SAR容易受到射频干扰(Radio Frequency Interference,RFI)的影响,而导致SAR图像质量的恶化。对于重复轨道InSAR来说,RFI的存在还会影响其干涉相位。针对此问题,该文将实测RFI信号加入仿真的典型圆锥场景回波,进行成像和干涉处理,给出了干扰前后的成像和干涉处理结果,分析了实测RFI对SAR图像幅度、相位和重复轨道干涉处理的影响。最后使用频域陷波方法对机载P波段重复轨道InSAR实际数据中的RFI信号进行干扰抑制,给出了干扰抑制前后的重复轨道干涉处理结果,验证了仿真分析的正确性,表明了该文干扰抑制方法对减小由RFI引入干涉相位误差的有效性。展开更多
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circular SAR （CSAR） imaging geometry, the system response function is in the form of the Bessel function which brings a high sidelobe, and the high sidelobe of CSAR will be an important factor influencing the interferometric coherence. The effect of the high sidelobe on the coherence is analyzed and deduced. Based on the interferometric characteristics of the slight difference in the viewing angles and the potential pixel off- set in the interferometric SAR （InSAR） images, a relation between the radar impulse response and the coherence loss function is derived. From the relational model, the coherence loss function due to the high sidelobe of CSAR is then deduced, and compared with that of the conventional SAR. It is shown that the high sidelobe of CSAR focusing signal will severely affect the baseline decorre- lation and coregistration decorrelation. Simulation results confirm the theoretical analysis and quantitatively show the baseline and coregistration decorrelation degradation due to the high sidelobes of CSAR.
基金Supported by the Key Project of National Natural Science Foundation of China (No. 60890070)
文摘Airborne Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) baseline error is a main error resource affecting the precision of velocity measurement of moving objects and therefore should be calibrated externally. The Jet Propulsion Laboratory (JPL) has proposed a calibration scheme for tasks of PacRim98 and PacRim2000 based on several static objects on the ground. In this paper, the influence of phase center uncertainty on baseline determination by using PacRim method proposed by JPL is analyzed. According to the analysis, the phase center uncertainty can cause a constant part of error to the result of baseline calibration. In order to deal with this problem, an improved calibration method on the basis of sensitivity equations and some ground moving targets, whose velocities are already known, is proposed in this paper. The simulation results show that our proposed calibration method has improved the accuracy of baseline calibration and has obviously prohibited the effect of antennas' phase center uncertainty.
文摘工作在低频段的SAR容易受到射频干扰(Radio Frequency Interference,RFI)的影响,而导致SAR图像质量的恶化。对于重复轨道InSAR来说,RFI的存在还会影响其干涉相位。针对此问题,该文将实测RFI信号加入仿真的典型圆锥场景回波,进行成像和干涉处理,给出了干扰前后的成像和干涉处理结果,分析了实测RFI对SAR图像幅度、相位和重复轨道干涉处理的影响。最后使用频域陷波方法对机载P波段重复轨道InSAR实际数据中的RFI信号进行干扰抑制,给出了干扰抑制前后的重复轨道干涉处理结果,验证了仿真分析的正确性,表明了该文干扰抑制方法对减小由RFI引入干涉相位误差的有效性。
