Research On 3D Video Imaging Technology Of Spaceborne Tracking Multi-antenna SAR

In recent years,synthetic aperture radar(SAR)has been playing an irreplaceable role in military early warning,situation assessment,disaster early warning,resource management and exploration,environmental governance,and marine resource development.With the innovation of data processing technology and the breakthrough of radar imaging mode and system,3D imaging and video imaging technology are gradually proposed and developed.As the top priority in satellite development,spaceborne synthetic aperture radar plays an important role in surface information inversion,surface deformation and moving target tracking due to its advantages of high resolution and wide mapping.High-resolution and three-dimensional imaging has always been an important indicator of spaceborne SAR performance,and the length of synthetic aperture duration will directly affect the resolution.In order to obtain a higher resolution capability in the slow time dimension of SAR images,the bunched SAR model has been proposed and studied.The bunching mode extends the observation in the slow time domain to a certain extent and further improves the resolution.Conventional SAR mode is conducted for fixed scene imaging,when appeared in the scene moving target and fled when the target imaging area,related data access,can't in order to realize the continuous dynamic observation and tracking of moving target imaging,need to study a new imaging model,this article is based on the demand,based on the circular track of SAR data acquisition mode,put forward the spaceborne tracking video multi-antenna SAR imaging model,discussed the imaging conditions,the model of circular motion under the condition of multiple antenna systems of echo signal modeling and research,fully integrated signal correlation processing technology,This paper studies 2d and 3D imaging of multi-antenna SAR,side lobe suppression,tracking filtering and high frame rate video frame formation,and then proposes a video imaging scheme for spaceborne tracking multi-antenna SAR.The main research contents and contributions are as follows:(1)Physical space conditions for three-dimensional imaging of spaceborne tracking video multi-antenna SAR are given,and a beam-adjusting model is proposed.Firstly,the structural relationship of satellite-borne circular track SAR for earth observation is given,and the physical conditions for the formation of satellite-borne circular track are comprehensively analyzed.According to the six-track parameter model of geostationary orbit,relevant parameters are set to realize the conditions of satellite-borne circular track.Then,a beam-adjusting model is established for moving target,and the expressions of angular velocity and velocity are derived for moving target.The six-rail parameter model and the beam adjustment model provide theoretical conditions for the three-dimensional imaging of spaceborne tracking video multi-antenna SAR.(2)Interactive multi-model tracking imaging method is proposed.In order to realize the three-dimensional imaging target of spaceborne tracking multi-antenna SAR,the geometric configuration and signal echo model of spaceborne circular trace SAR are presented,and the fuzzy function of circular trace SAR imaging and the resolution analysis of partial aperture and full aperture are performed.Then,on the basis of the previous section,the signal echo model under the multi-antenna system is presented,and the signal processing results are further understood by analyzing the point diffusion function.Furthermore,the imaging method of time domain processing is given by the backward projection algorithm(BP).Then,in view of the high side-lobe characteristics of circular trace SAR imaging,the side-lobe suppression method based on space toe cutting filter(SVA)was studied.Through the parameter optimization of the ascending cosine function,the side-lobe suppression effect of the point target was obvious while the width of the main lobe was guaranteed to remain unchanged.Finally,based on the interactive multi-model filtering theory and combined with the backward projection algorithm,an interactive multi-model tracking imaging method is proposed under the tracking mode condition to realize the continuous tracking imaging of moving objects in the scene,which further expands the observation dimension of time.(3)In order to realize the high frame rate imaging condition of video SAR,the data processing structure of shift register is introduced,and the image resolution is improved by dividing the molecular aperture and sub-image fusion.Firstly,the configuration of the spaceborne tracking video multi-antenna SAR studied in this paper is presented,and the video frame extraction method of video SAR is discussed,and the relationship between the video frame rate and resolution under the condition of non-overlapping and overlapping is analyzed respectively.Secondly,a fast frame structure based on shift register is introduced,and the method of fast frame formation is given through analysis.Finally,the process of sub-image fusion in the sub-aperture imaging mode is presented,and the image resolution can be further improved by sub-image fusion.The above study spaceborne tracking video multi-antenna SAR three-dimensional imaging technology,is based on the moving target is fled the imaging area of the problem and to establish a new imaging model,some of these issues is also a technical problem to be solved,the resolution spaceborne circle trace the characteristics of SAR and spaceborne tracking video multi-antenna SAR echo signal model,on the basis of strict theoretical derivation and science and hardware-in-the-loop simulation data of the experiment,finally get spaceborne tracking video multi-antenna SAR three-dimensional imaging and the results of the video frame.The research in this paper can not only give full play to the configuration characteristics of multi-antenna SAR and improve the 3d imaging performance of the target,but also the proposed beam adjustment technology,tracking imaging technology and fast framing structure have reference significance and application value for underwater vehicle detection and other fields.