Research On Spaceborne SAR Echo Simulation Technology In Complex Electromagnetic Environment

Spaceborne synthetic aperture radar(Synthetic Aperture Radar,SAR)is an active electromagnetic wave imaging system that relies on satellite platforms to realize earth observation.In the last few years,it has been widely used in many fields such as military,civilian and commercial.However,with the invention and application of various functional electronic devices,the signals in the electromagnetic space are dense,which makes the working environment of spaceborne SAR more complicated,affects the imaging quality of echoes,and hinders the functional judgment of the on-orbit spaceborne SAR equipment.Simulation of spaceborne SAR echo data in complex electromagnetic environment is still a hot topic of research.Echo simulation technology,as an indispensable auxiliary verification method in SAR technology research,also needs to be constantly replaced to meet the functional requirements of multi-mode.However,the current simulation system still has the problems of structural redundancy and high coupling,which makes it inconvenient to add errors to the spaceborne SAR and update the system.In this paper,we used computer to carry out an all-digital modeling of the spaceborne SAR echo simulation in a complex electromagnetic environment,and built a complete end-to-end simulation system to realize the echo data simulation and evaluation of the scene,it provided an analysis basis for the fault location of the spaceborne SAR.The main research contents were as follows:(1)The spaceborne SAR echo simulation technology was studied,and an end-to-end multi-mode spaceborne SAR modular simulation system was established.According to the established spaceborne SAR signal model,the simulation system was divided into 15 modules,and established a multi-mode spaceborne SAR simulation system with low coupling and high scalability.For the authenticity of the simulation and the evaluation of the error effect,various error factors such as channel,link,and ambiguity were also introduced.(2)The simulation technology of electromagnetic environment signal was studied,and constructed the echo simulation system in complex electromagnetic environment.Through the analysis of the geometric relationship between the satellite and the ground,the coupling model of the electromagnetic environment signal and the echo signal was established,and expanded the function of the spaceborne SAR echo simulation system.Finally,completed the spaceborne SAR echo simulation under the complex electromagnetic environment,and analyzed the electromagnetic environment signals.The digital simulation system reduced economic costs of field experiments,and had high system scalability and portability,it can be applied to engineering practice.