Research On SAR 3D Imaging Method Based On UAV Group

Typical SAR(synthetic aperture radar)3D inversion technology mainly includes tomographic SAR,array SAR and circular SAR.Circular SAR has many advantages compared with tomographic SAR and array SAR because of its unique geometric model of the radar platform moving around the detection target scene.Firstly,because the radar platform moves 360 ° around the scene,the pulse signal from the radar always points to the center of the detected scene,so it can achieve sub wavelength twodimensional spatial resolution;Secondly,the circular SAR moves around the center of the detection scene,which can detect the scene from various perspectives,avoiding the problems of shadow and target masking in traditional SAR imaging.For single circle SAR imaging,multi baseline circle SAR can obtain high-resolution three-dimensional image of target,which plays an important role in radar image interpretation.In recent years,civil UAV technology has made great progress.Due to the advantages of low cost of construction and use,simple and easy to operate,flexible flight trajectory control,low flight,low speed and little radar cross section,UAV is not easy to be detected by radar,so it has important application value in many industries,such as aerial photography,ground reconnaissance and so on.The core content of this paper will focus on single circle SAR imaging and threedimensional SAR imaging based on UAV group as fllows:(1)This paper discusses the mechanism of point target inversion from circular SAR signal,realizes the most common BP algorithm,and then carries out the twodimensional simulation of single point target in the center of scene.(2)This paper discusses the expression of PSF of circular SAR system under the condition of linear frequency modulation signal and isotropic single point target are located in the center of the scene,then leads to the sidelobe problem of circular SAR system,and then uses the traditional sidelobe suppression method,and discusses its effect.Finally,a sidelobe suppression algorithm based on base pursuit algorithm is proposed,and compared with BP algorithm,its effectiveness is verified.(3)The SAR 3D imaging method based on UAV group and synthetic aperture radar is analyzed.The signal model of multi baseline circular SAR is discussed,and an iterative adaptive imaging algorithm in altitude dimension is proposed in UAV group SAR system.After that,the effectiveness of the iterative adaptive algorithm is verified by discrete point targets and the data released by AFRL.