In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, gr...In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term.展开更多
甚长基线干涉测量(very long baseline interferometry,VLBI)台站钟差的补偿误差将导致VLBI时延观测量参考历元的偏离,进而对世界时(universal time,UT1)的准确估计产生影响。台站钟差包含格式器钟差和设备时延,设备时延是影响钟差补偿...甚长基线干涉测量(very long baseline interferometry,VLBI)台站钟差的补偿误差将导致VLBI时延观测量参考历元的偏离,进而对世界时(universal time,UT1)的准确估计产生影响。台站钟差包含格式器钟差和设备时延,设备时延是影响钟差补偿精准度的关键因素。上海佘山VLBI站是全球测地参考框架的基准站,有必要评估该站的钟差补偿精准度。利用该站2002—2017年国际测地观测数据的相关处理结果,分析了相关处理机对佘山站钟差的补偿精度。结果表明,不同VLBI相关处理机对佘山站模拟终端的设备时延补偿具有较好的一致性和长期稳定性,满足UT1测量精度需求,但是上海相关处理机对佘山站数字化终端的设备时延补偿存在大于1μs的系统差,有必要进一步改进钟差搜索方法和提高钟差补偿精度。展开更多
A joint-pixel clutter suppression method based on slope compensation is proposed in this paper, In order to eliminate the effect of the terrain interferometric phase caused by the cross-track baseline in hybrid baseli...A joint-pixel clutter suppression method based on slope compensation is proposed in this paper, In order to eliminate the effect of the terrain interferometric phase caused by the cross-track baseline in hybrid baseline InSAR, the local independent identical distribution of the clutter is satisfied by using the slope compensation technique, and thus the clutter can be suppressed successfully by using the orthogonality of the clutter subspace and the noise subspace. This approach utilizes the information contained in the current pixel as well as in its neighbors, showing robustness to the image coregistration errors. Both the simulated data and the real airborne data are used in proving the validity of the presented approach.展开更多
基金supported by the National Key R&D Program of China (2018YFC1508502)the National Natural Science Foundation of China (41601569,61661043,61631011)the Science and Technology Innovation Guidance Project of Inner Mongolia Autonomous Region (2019GG139,KCBJ2017,KCBJ 2018014,2019ZD022)。
文摘In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term.
文摘甚长基线干涉测量(very long baseline interferometry,VLBI)台站钟差的补偿误差将导致VLBI时延观测量参考历元的偏离,进而对世界时(universal time,UT1)的准确估计产生影响。台站钟差包含格式器钟差和设备时延,设备时延是影响钟差补偿精准度的关键因素。上海佘山VLBI站是全球测地参考框架的基准站,有必要评估该站的钟差补偿精准度。利用该站2002—2017年国际测地观测数据的相关处理结果,分析了相关处理机对佘山站钟差的补偿精度。结果表明,不同VLBI相关处理机对佘山站模拟终端的设备时延补偿具有较好的一致性和长期稳定性,满足UT1测量精度需求,但是上海相关处理机对佘山站数字化终端的设备时延补偿存在大于1μs的系统差,有必要进一步改进钟差搜索方法和提高钟差补偿精度。
基金Supported in part by the National Nature Science Foundation of China (Grant No. 60802074)the Program for New Century Excellent Talents in University
文摘A joint-pixel clutter suppression method based on slope compensation is proposed in this paper, In order to eliminate the effect of the terrain interferometric phase caused by the cross-track baseline in hybrid baseline InSAR, the local independent identical distribution of the clutter is satisfied by using the slope compensation technique, and thus the clutter can be suppressed successfully by using the orthogonality of the clutter subspace and the noise subspace. This approach utilizes the information contained in the current pixel as well as in its neighbors, showing robustness to the image coregistration errors. Both the simulated data and the real airborne data are used in proving the validity of the presented approach.
