Research On Irradiance Measurement Technique Of Infrared Target Simulator

The objective of project,"Research on infrared spectral irradiance measurements of infrared target simulator", is to develop a standard precision irradiance measuring instrument of infrared target simulator with the uncertainty better than 15%, to meet the urgent demand of establishing calibration of IR target simulator and unifying spectral irradiance value.Based on establishing diommtric calibration of IR target simulator as the special requirement and developing measuring instrument, the dissertation deeply focuse on the working principle of IR target simulator, mathematical model for calibration, practical data processing method and instrument principle. The main creative researches are as follows:1. The study of the influence of infrared background radiation on irradiance measurement based on Monte-Carlo method is presented and realized by algorithm. The probability model among background radiation, targets and the integration infrared radiometry is established. The effects of spatial distribution of background radiation on irradiance measurement are analyzed in details with the assumption of that the target is in mirror-diffuse reflecting model. Moreover, the dependence of background radiation on radius in hemispherical space is studied. A difference equation is established by using two-temperature method to eliminate the background effects.2. The projection pursuit method with partial least square regression method is applied in irradiance measurement of infrared target simulator. According to the problems of multi nonlinearity among independent parameters and the complicated problems of nonlinearity between dependent variable and independent variable in measurement, the dissertation combines the two methods to establish a coupling model with projection pursuit based on partial least squares regression to predict the irradiance value of infrared target simulator. Simulation results show that the uncertainty of the target is reduced and the reliability is improved by data fusion.3. Develop an irradiance measurement system of infrared target simulator. The measurement system, which includes the optical path, electronic path, and mechanical path, has been developed. The spectrum regions of this system are in near infrared, middle infrared and far infrared. To decrease the influence of the suppression on stray radiation in the measurement, a shielding structure is used. The collimated system of beam, the reflection system, the modulated light system and the receiving system of photoelectric signal have been designed. The circuit system which can receive and process the weak photoelectric signal is designed. The whole measurement process is controlled by computer.According to technical requirements of"Infrared Radiation Measuring Instrument Verification of China Aerospace", the parameters of the standard measuring instrument are measured. The results show that the new instrument adopting the above-mentioned techniques can fully reach the measurement precision required.At last, the actual measurement of infrared target simulator is accomplished by the system. The distributions of radiation on irradiance measurement of infrared target simulator can be reconstructed separately by chaos genetic algorithm. The results prove further the validity of theoretical analysis and accuracy of actual measurement. The irradiance measurement near room temperature is realized.The researches in this dissertation provide the firm theoretical and technical base for the establishment of IR target simulator calibration standard.