Research On Interferometric Synthetic Aperture Radar Imaging Technology

Interferometric synthetic aperture radar(InSAR)can achieve high-resolution,high-precision three-dimensional imaging,which has important value in many civil and military fields.InSAR is based on SAR to achieve height measurement by two or more images interference,which involves image registration,phase unwrapping and other key technologies.In addition,obtaining high quality SAR image is also an important step.The main work of this paper includes the following aspects:1.This paper introduces the basic principle of SAR imaging,then introduces the principle of InSAR imaging,and analyzes the phenomenon of ground effect in InSAR imaging.2.Motion compensation is an important part of InSAR imaging.This paper analyzes the error model of InSAR imaging.First of all,the offset of Doppler center frequency needs to be compensated.In this paper,the energy method and autocorrelation function method are studied,and the simulation results are given.The key problem of motion compensation is image focusing,which mainly includes phase gradient autofocus(PGA)and map-drift(MD).In this paper,the two methods are studied and improved,which are verified by simulation and real data.3.InSAR realizes height measurement by two(more)images interference on the basis of SAR.InSAR imaging includes many key steps,such as image registration,remove flat-earth effect,noise reduction and filtering,phase unwrapping,etc.This paper analyzes each step and gives effective methods,which are verified by simulation and real data imaging.4.Phase unwrapping is a key problem in InSAR imaging.The least square method is a common phase unwrapping method,which can achieve good unwrapping effect in the case of small terrain fluctuation,but it has a large amount of calculation,and the unwrapping effect is poor in the scene with discontinuous phase change and large phase change.Therefore,this paper proposes a phase unwrapping method based on monopulse angle measurement technology,introduces the principle of this method,compares the unwrapping effect of this method and the least square method in different scenes through simulation experiments,and gives the 3D imaging results of real data.