Spaceborne Multistatic SAR Tomography

SAR Tomography(TomoSAR),as an extension of traditional single-baseline interferometric SAR(In SAR),uses multi-baseline SAR data arranged in the normal plane of range direction to form synthetic aperture in the height direction while maintaining the full azimuth aperture,thus obtaining two-dimensional high-precision resolution imaging in azimuth-height direction,which also makes SAR truly qualify as three-dimensional(3D)imaging,and gradually become the mainstream of SAR 3D imaging technology.On the other hand,multistatic SAR system has great application potential in high-resolution wide-swath imaging,moving target detection,interferometric altimetry,3D/4D imaging,anti-interference,multi-level imaging,etc.,which has attracted the research interest and extensive attention of scholars,and gradually becomes one of the hot spots in today’s research field.Therefore,in order to meet the strong demand for high-precision resolution,wide coverage and multi-dimensional direction of SAR imaging,the concept of Spaceborne Multistatic TomoSAR(SMS-TomoSAR)system has been proposed.Spaceborne multistatic TomoSAR system combines the characteristics of monostatic TomoSAR and multistatic SAR,and has multi-baseline,multi-temporal detection capabilities in spatial and temporal dimensions,which can further realize spatial resolution in the height direction(3D imaging),and small surface deformation measurement of the 3D ground scene(4D imaging).Spaceborne multistatic TomoSAR is a pre-develpoed system.On the one hand,there is no measured data as a support.On the other hand,there are a series of key technical issues such as space-time baseline optimization design,spatial trasmission phase error compensation,and high-resolution imaging,etc.,which directly affect the performance of high-resolution imaging along the elevation direction of SMS-TomoSAR system.This paper thakes the multistatic system as a starting point,and fouces on the realization of high-precision 3D/4D imaging of spaceborne multistatic TomoSAR system.The above-mentioned key technologies affecting the imaging performace of the system are deeply studied,and the corresponding theories and methods are proposed.