Research On Processing Method Of Large Field Of View 3D Micro-deformation Monitoring Radar

Ground-based micro-deformation monitoring radar has been widely used in the field of slope landslide and micro-deformation monitoring of artificial buildings.However,due to the geometric distortion of two-dimensional radar images,it is impossible to monitor the deformation of complex terrain areas such as high and steep slopes.Three-dimensional imaging of ground-based micro-deformation monitoring radar can fundamentally eliminate the geometric distortion of two-dimensional radar images,which has been widely studied in recent years.In terms of micro-deformation monitoring,differential interference technology has been widely used in the field of micro-deformation monitoring such as slope.However,due to the long revisit period,there is a serious phase wrapping problem in the monitoring of the micro-deformation of the target with fast deformation speed,resulting in unwinding errors and even unable to monitor.To meet the needs of large field of view monitoring,the observation model of ground-based spherical aperture micro-deformation monitoring radar was established,and a three-dimensional fast imaging method of ground-based spherical aperture radar was proposed.The micro-deformation monitoring of the targets with fast deformation speed is realized by the displaced phase center antenna technology and the along-track interferometry technology.The specific research work is as follows.1.Aiming at the observation model of ground-based spherical aperture microdeformation monitoring radar,a three-dimensional radar echo model considering the constraint of antenna spatial angle is established,and the quantitative relationship between the antenna beam width and the target irradiation range is derived,and the sampling criteria and three-dimensional resolution under this model are analyzed.2.Aiming at the problem of large amount of computation in traditional back-projection algorithm,a nonlinear range model is established.The range compensation factors in azimuth and elevation are derived by Taylor expansion of slant range.At the same time,an error control mechanism is introduced,and a spherical aperture sub-regional phase iterative imaging method is proposed.Under the premise of ensuring the imaging quality,this method converts the root index operation to the addition and multiplication operation when solving the range by using the method of solving the range by using the progressive formula of the range compensation factor,and improves the algorithm efficiency.3.Aiming at the problem of deformation monitoring of fast moving targets,a dualchannel GB-SAR model was established,and the maximum detectable speed under this model was analyzed.The ground-based micro-deformation monitoring radar can realize the micro-deformation monitoring of fast deformation targets through the displaced phase center antenna technology and the along-track interferometry technology.