Research On The Effect Of Vibration And Flight Attitude On The Image Quality Of Airborne Camera

With the development of the aerospace field,airborne cameras are widely used in agriculture,public safety,military and other fields.With the continuous improvement of the airborne camera resolution requirements,the impact of the aircraft's vibration and flight attitude changes on imaging quality is also more obvious.Therefore,it is of great practical engineering significance to study the impact of onboard aircraft vibration and flight attitude changes on the imaging quality of cameras,to improve the imaging quality of onboard cameras.This paper analyzes the impact of the vibration and flight attitude on the imaging quality of the airborne camera optical system,and develops a three-axis stable platform equipped which can equip the camera.Based on theoretical analysis and simulation analysis,the self-developed airborne camera was used for vibration imaging experiment and outdoor field test experiment.To verify the airborne camera's imaging characteristics and stability,The image quality of the captured images were analyzed.In order to solve the problem of the impact of carrier-borne vibration on the imaging quality of the airborne camera,the method of optical-mechanical integration analysis was used.The airborne camera structure modeling,structural finite element simulation,optical element rigid body displacement and surface distortion,optical system modeling and imaging quality evaluation are effectively connected in series.Taking the self-developed airborne camera as the research object,first of all,the integrated model method is used to perform finite element preprocessing on the airborne camera using HyperMesh software.Using NASTRAN software for simulation analysis,the structural response of the optical element under vibration load excitation was obtained.Then on the basis of finite element simulation analysis,quantitative analysis of the rigid body displacement and surface distortion changes of optical components.Finally,the optical system model of the airborne camera is established through ZEMAX,and the optical modulation transfer function and point map are used as imaging quality evaluation indicators to analyze the impact of vibration on the imaging quality of the optical system.In order to solve the problem of the impact of the carrier's flight attitude change on the imaging quality of the camera optical system,a coordinate transformation method was used to establish an image shift calculation model.Derive the equations of deflection,pitch and roll of the push-broom airborne camera caused by the attitude change of the carrier aircraft,analyze the effect of image movement on the imaging quality of the airborne camera,put forward the requirements of the imaging quality on the attitude accuracy,and determine the stability of the platform compensation accuracy requirements.A three-axis stable platform was designed for image motion compensation,and the finite element simulation analysis is performed on the stable platform,the performance test of the stable platform was performed.The experimental results show that the angular velocity accuracy,feedback resolution,and rotation accuracy of the three-axis stable platform all meet the design requirements,which can effectively compensate the image shift caused by the attitude change and meet the imaging quality requirements.Finally,the vibration imaging experiment,indoor imaging experiment and outdoor field test experiment were carried out on the airborne camera.Using the edge method to measure the transfer function of the captured images and evaluate the imaging quality,the results of the vibration imaging experiment are consistent with the theoretical analysis.