Design And Implementation Of Simulation Software For Spaceborne SAR

Synthetic aperture radar(SAR)is a kind of microwave remote sensing equipment which can obtain high-resolution ground images.It has the characteristics of all-day and all-weather,and is widely used in military and civil fields.Compared with airborne SAR,spaceborne SAR has a larger observation range and is not subject to national airspace control.However,in the research of spaceborne SAR,it is often affected by many adverse factors,such as expensive equipment,difficult data acquisition,difficult hardware debugging,and so on.Simulation by computer has become an important way to study spaceborne SAR.The spaceborne SAR is studied in this thesis,and a complete set of spaceborne SAR simulation software is designed and implemented.The main work of this thesis is summarized as follows:Firstly,the simulation requirements of spaceborne SAR are analyzed in this thesis,and a software design scheme is proposed based on software design principles.The simulation software is divided into two parts: system simulation and display control interface.The system simulation part is written in Matlab,and the hybrid programming method of Matlab and CUDA C is used to achieve GPU parallel acceleration.The display control interface of the software is designed by the Matlab graphical user interface(Matlab GUI)to provide a friendly human-computer interaction interface.Secondly,according to the software design scheme,four functional modules of satellite orbit simulation,echo generation,imaging processing,and image quality evaluation are modeled and simulated.In the satellite orbit simulation module,the satellite-earth geometric model is established,and the satellite coordinates,satellite velocity,and aiming point coordinates are calculated by the geometric model.In the echo generation module,the echo of point targets and area targets can be simulated in various working modes.Different imaging algorithms can be used to process the echo data in the imaging processing module.In the image quality evaluation module,the imaging results of point targets and area targets can be evaluated.Then,aiming at the serious time-consuming problem of echo simulation and imaging processing when the amount of data is large,the parallelism of echo generation algorithm and imaging algorithm is analyzed.The parallel GPU acceleration of echo generation algorithm and imaging algorithm is achieved by using the hybrid programming method of Matlab and CUDA C,and compared with the program before acceleration,the effectiveness of the acceleration method is verified.Finally,Matlab GUI is used to design the display control interface of the software,the visualization of the program is achieved,and the function of the simulation software is tested.The hybrid programming method of Matlab and CUDA C to achieve GPU acceleration is used in the simulation software designed in this thesis,and the display control interface of the software is designed by the Matlab GUI to achieve the visualization of the program.The whole process of spaceborne SAR from satellite orbit simulation to image quality evaluation can be simulated in the simulation software implemented in this thesis,and imaging processing of external echo data and quality evaluation of external SAR images are supported.The simulation software implemented in this thesis has the advantages of simple operation,accurate results,high operating efficiency,and friendly human-computer interaction and has certain positive significance to promoting the development of spaceborne SAR technology.