Design Of The Airborne Freeform-surface Conformal Optical System

Modern war puts forward higher and higher requirements on stealth performance and aerodynamic performance of military aircrafts.Airborne infrared detection systems demand conformal design,which brings several advantages.Due to the conformal stealth design,the air resistance and turbulence are reduced,and larger field of view of the sensor is obtained.At the same time,the aerodynamic heating effect and infrared radiation of aircrafts decrease,the radar cavity reflection is eliminated,and the Radar Cross Section(RCS)is reduced obviously.However,the conformal optical window brings a lot of asymmetric aberration to the optical system,which makes the design of the airborne conformal optical system quite difficult.In this dissertation,the distributed aperture system of a certain type of aircraft is studied,the material of the optical window is chosen considering the installation position,function and conformal requirements,and then the conformal design is carried out using freeform surface design technique.The key problems in the freeform surface design technique including modeling,optimization and simulation are solved.The design of freeform surface conformal optical window is initially completed.The main points of the dissertation including:Firstly,the design idea of the conformal optical system is introduced.According to the preparation of infrared optical material at home and abroad,the proper infrared optical glass for this issue is chosen.Secondly,the theoretical analysis of airborne conformal optical system aberration characteristics and adjusting methods is carried out.Using CODE V optical system design software,the fitting of the freeform conformal surface,the modeling of the freeform-surface conformal optical window and the optimization of the design of the freeform-surface conformal optical window are finished.Then the simulation and assessment for the designs of both ideal optical system and actual optical system are carried out.Finally,through research and tolerance optimization,the proper tolerance allocation and machining feasibility analysis for freeform-surface conformal optical window are completed.Also the project feasibility of the design in this dissertation is examined.