Design And Implementation Of Simulation Software For Spaceborne SAR-GMTI

Synthetic aperture radar(SAR)can not only obtain high-resolution images of the target observation area,but also achieve ground moving target indication(GMTI).Compared with the airborne SAR-GMTI system,the spaceborne SAR-GMTI system is not subject to national airspace control.It can obtain a larger observation range and plays an important role in military and civil fields.However,the echo data of the spaceborne SAR is not easy to obtain.The working environment is more complicated and the equipment is more expensive.In order to verify the working process of spaceborne SAR-GMTI system conveniently,the modeling and performance simulation for spaceborne SAR-GMTI system by computer simulation can effectively reduce the cost and improve the experimental efficiency.Based on the study of spaceborne SAR-GMTI,a complete set of simulation software for spaceborne SAR-GMTI is developed in this thesis.The software has an easy-to-operate input and output interface,which can fully describe the process of spaceborne SAR imaging and GMTI.It can also evaluate the imaging quality of spaceborne SAR.First of all,the software design scheme is put forward based on Simulink + Matlab graphical user interface(GUI)in this thesis.The software consists of three parts: parameter setting,system simulation and display control.System simulation is the core of the software,which completes all functions of the system.This part realizes the modularization of the simulation system based on Simulink;Parameter setting and display control provide an easy-to-operate input and output interface.Parameter setting and display control realize the visualization of system by Matlab GUI.Then each module of the system is modeled,simulated and analyzed,including satellite orbit module,echo generation module,beamforming module,imaging algorithm module,image quality evaluation module and GMTI module.The satellite motion model is established according to the satellite orbit parameters seted and the satellite’s position,sub-satellite point position and aiming point position are calculated in the satellite orbit module;Different SAR echo models are established according to different working modes and the module can simulate dot matrix echo and scene echo separately;The beamforming module performs beamforming according to the configuration of the array antenna;Different imaging algorithms can be selected to process the echo data in different working modes in the imaging algorithm module;The imaging quality of point targets and area targets can be evaluated separately in the image quality module.A two-channel echo model is established in the GMTI module.In the still scene,displaced phase center antenna(DPCA)technology or along-track interferometry(ATI)technology is used to detect the moving target.Finally,the Matlab GUI was used to achieve parameter setting and display control,and the input and output interface of the software was designed and the system is tested as a whole.Based on Simulink,the componentization and modularization of the simulation system are realized.At the same time,Matlab GUI is used to achieve parameter setting and display control,which is convenient for users.The simulation software can realize system simulation in multiple working modes including striping mode,bunching mode,and GMTI mode.It can call a variety of imaging algorithms for imaging processing and can make an assessment of imaging quality.It has certain positive significance for the study of the spaceborne SAR-GMTI system.