Transmissivity Measuring System Of The Plume Penetrated By 10.6μm Laser

The plume is a kind of smog which is generated by solid engines of rockets or missiles when they are running, it has a shape of feather. Laser-guided weapons can trace rockets or missiles through detecting their plumes. The plume transmissivity by laser will directly decide the performance and precision of laser guidance. We can optimize the propellant of solid engine so as to improve the transmissivity of generated plume and decrease the threats caused by laser-guided weapons. Therefore, we need to research the transmissivity characteristic of different plumes penetrated by laser.The main task of this subject is to develop a transmissivity measuring system of the plume penetrated by 10.6μm laser. We can use this system to measure the plume transmissivity by 10.6μm infrared laser, and make an estimation of the invisibility performance of the plume in this wave band. Through the estimation, we are able to find out the flaw of the plume in invisibility performance in time, then we can make a better improvement on the solid engine until the generated plume is in accordance with our demand. This measuring system consists of two major parts: infrared optical system and signal collection,data processing system. The paper designs 10.6μm infrared optical system through theoretical calculation and analysis, and adopts reverse Galileo telescope in the emission part of optical system to collimate the laser beam. The paper also elaborates the composition and work process of signal collection,data processing system, including the design of signal processing circuit which amplifies and filters conversed voltage signal, and the design of digital circuit which samples,holds,converses,stores and sends analog signal. Besides, we make the assembly language program for SCM system based on ATMEL89S52, and design PC software based on VC++. The flow chart of SCM program and the function menu for PC software are also presented. At last, we use 3.4μm LED to have a test, and get the transmissivity characteristic of paper and smoke penetrated by 3.4μm middle infrared light.Because of the limited time, in the subject there are still many problems needing further solutions and improvements.