Research On Miniature Telefocal Multiband Common Aperture Optical System

Science technology are becoming more and more complicated and in-depth in the process of using,which requires constant updating and improvement,So as the optoelectronic system.Optoelectronic system has been widely used in military reconnaissance,camouflage identification,geological exploration,environmental testing,fire prevention and disaster relief and other fields.As an important,effective and accurate observational radiation equipment,its status has become more and more important.During use,the optoelectronic system has also developed with finding the defects and the improving.As a kind of the optoelectronic systems,Tracking and aiming system detects and determines the target,and then conducts target recognition and tracking.In the process of tracking,the target characteristic information is obtained and fed back to the processing system for settlement.Therefore,the detection and determination of the target is guarantees for the performance of the optoelectronic system.The traditional distributed structure limits the size of the optical aperture,which limits the detection range of the system.Single-waveband image system can only reflect part of the characteristics of the target.In order to obtain target information accurately and comprehensively and without interference,comprehensive image information of different bands needs to be integrated to achieve accurate target tracking around the clock.Foreign countries have carried out the development of multi-band imaging system a long time ago.In this paper,based on specific innovative projects,some problems in the design of multi-band common-aperture aiming tracking system are studied.The key technologies such as the mosaic optical window,multi-band co-aperture optical system design,detection,setup and alignment,and laser emission and reception with a aperture are studied.Two sets of airborne multi-spectral optical system with common-aperture are designed.One is used for airborne ball-mounted optoelectronic system and one is used for airborne embedded optoelectronic system.Using the theory of primary aberration and PW algorithm,the initial structure of the transmissive optical system has finally been optimized to meet the desired requirements.The stray light analysis and suppression of the designed system offer a reference for the design of a reasonable shade and stop ring.The infrared system needs further analysis of its cold reflections.By the suitable mathematical model of cold reflectivity and the actual optical practical needs,analysis of Cold reflections of airborne IR optics and changes of the cold reflections during focusing can guides the optical design to further refine and optimize.In order to eliminate the influence of the backscattering noise on the echo signal detection in the co-aperture laser irradiation,ranging and spot tracking system,the method of backscattering noise elimination by optical means is proposed based on the polarized characteristics of the laser pulse.The components of the backscattering noise in the co-aperture laser system are analyzed by Jones matrix;the components of backscattering noise are measured in experimental,which based on the principle of co-aperture laser system.Theoretical analysis and experimental results show that the main components of the backscattering noise in the co-aperture laser system are and polarized laser pulses.Thus,to eliminate this backscattering noise,the approach of improving the degree of linear polarization of the emitted laser pulse to reduce the component of backscattering noise,and improving the optical elements' polarization extinction ratio in the reception optical path to eliminate the component is feasible.Moreover,this method has stable,efficient and wide bandwidth characteristics.It is shown in experimental result that main component of backscattering noise is linear polarization pulse vibrated along the direction p.Therefore,the method to improve extinction ratio of polarized light for laser pulse emission path shall be used to filter polarization pulse s in backscattering noise and linear polarization element with high extinction ratio of polarized light shall be used in receiving light path so as to filter polarization pulse p in backscattering noise,which can rapidly and effectively filter influences of backscattering noise in the system on echo signal detection and has reference significance to design of co-aperture laser system.Based on the knowledge of diffraction optics and Fourier transform and other mathematical methods,the mathematical model of the influence of the mosaic optical window on the transfer function of the optical system is established.The relationship between the parameters of the mosaic optical window,the parameters of the optical system and the transfer function of the optical system is analyzed.The mathematical model can guide the design of the mosaic optical window according to the requirements of the optical system.Aiming at the design of a suitable detection scheme for the off-axis three-axis aspheric design,the corresponding compensator is designed and the processed aspheric surface is re-inspected.Cassegrain system and off-axis three anti-reflective system installation work are accomplished.In summary,the subject reserves a large number of theoretical and practical experience for the study of airborne common-aperture optical system,which provides technical support for the design of long distance detection and multi-functional on-board photoelectric sighting system.