Research On Technology Of Passive Detection Of Air Targets By Millimeter Wave

Millimeter-wave passive detection technology is one of the passive detection technologies.This thesis studies the millimeter wave passive detection method for air targets mainly focuses on the radiation characteristics of the air target,the millimeter wave radiative transmission characteristics of the target and the maximum detection capability of the millimeter wave radiometer.The main research content includes:(1)Analyze the mechanism of the millimeter wave passive detection of the air targets,establish a detection model of the millimeter wave radiometer to detect air targets.According to the analysis of millimeter wave radiation characteristics,the millimeter wave radiation brightness temperature of the metallic body of the aircraft and stealth aircraft are obtained.The fluid simulation software was used to simulate the flow field of the aircraft tail flame,and the millimeter wave radiation brightness temperature of the tail flame was calculated.(2)Based on the MPM model,the absorption of millimeter wave by atmospheric components is calculated,and the attenuation of millimeter wave radiation in different weathers under standard atmosphere is calculated.The atmospheric refraction model is established,and the total attenuation of the path-temperature of the millimeter wave radiation in the air target is calculated by the equivalent earth radius method.According to the atmospheric attenuation characteristics of the millimeter wave,the sky background radiation brightness temperature without a target is simulated.(3)According to the analysis of target radiation characteristics and radiation transmission characteristics,the key parameters are designed for the radiometer,and the theoretical maximum detection distance of the millimeter wave radiometer is evaluated.(4)The IF amplifier was designed to improve the original radiometer.The performance of the radiometer was evaluated by the civil aircraft detection trial.The trial results show that the use of a millimeter-wave radiometer to detect a target of one or two kilometers performance well.