The Modeling And Implementation Of The New Model Of SAR Radar Simulation System

Synthetic aperture radar(SAR)is a powerful and well-established microwave remote sensing technique that enables two dimensional(2-D)high-resolution measurements of the Earth's surface from long distance.SAR also is a powerful and effective tool for the retrieval of geographical information because of its capability to work under all weather conditions,day and night.It has been widely used in the national defence and civil industry.For applications with different requirements,many imaging modes have been developed in the literature,such as,Stripmap mode,Sliding Spotlight mode,and Terrain Observation by Progressive Scans mode(TOPS mode).However,among different imaging modes,the echo signals have their own characteristics.As such,the imaging algorithms are different.This dissertation focuses on the Modeling and Simulation of TOPS SAR and Sliding Spotlight SAR.Based on the different imaging geometry and by the analysis of the echo data,The imaging approaches introduced are deeply studied.Afterwards,on the software platform of the new modeling SAR system,the imaging algorithms models are built,and then,the simulation results were applied to verify and analyze its performance.The main content of the thesis is summarized as follows:Initially,the work modes of Radar and the summary of the software platform of the new model of SAR radar system are presented.After decades of improvement and perfection,the radar technology is becoming more and more flawless.From the conventional radar with the simple principle and function to the new modeling radar with various functions and a wide range applications,great progress had been made in the radar technology.Then,the working modes of different radar systems were introduced in detail.Taking several typical SAR working modes as an example,such as Stripmap mode,Scan SAR mode,TOPS mode and so on,presenting their basic principles in detail with their working diagrams and time-frequency distribution diagrams.It is essential to make comparision between the new working modes and traditional working modes,and then,giving an outline of the the software simulation platform of the new modeling SAR system.Finally,several modules in common use were recommended,such as the echo generation module,pulse compression and so on.Secondly,the modeling and simulation of TOPS SAR was introduced.A new signal model for TOPS SAR was proposed to provide a theoretical basis for the establishing of the Baseband Azimuth Scaling algorithm model.According to the characteristics of the azimuth signals,simple analyses were conducted on the them.Afterwards,the specific steps of BAS imaging process under 0 degree were analyzed and the algorithm flow chart was given.BAS imaging algorithm module was constructed based on the simulation parameters,and the testing simulation model of BAS was built on the software platform of the new modeling SAR.Then,the simulation results were compared with the results based on MATLAB to verify and analyze its performance and accuracy.Finally,the modeling and simulation of the Sliding Spotlight SAR was proposed to provide a theoretical basis for the establishing of the Extended Chirp Scaling algorithm model.A new appropriate signal model was proposed for the Sliding Spotlight SAR with high resolution.According to the characteristics of its azimuth signals,simple analyses were conducted on the them,and the definitions of azimuth resolution and range resolution were put forward.Afterwards,the specific steps of ECS imaging process under 0 degree were analyzed and the algorithm flow chart was given.ECS imaging algorithm module was constructed based on the simulation parameters,and the testing simulation model of ECS was built on the software platform of the new modeling SAR.Then,the simulation results were compared with the results based on MATLAB to verify and analyze its performance.