A Study Of Image Characteristic Of Infrared Point Target Detected By Space-borne Warning System

Space-borne infrared early warning system plays a very important role in Ballistic Missile Defense. During the powered phase, missile could be detected and tracked by IR imaging sensor on the geosynchronous orbit satellite. Because of low spatial resolution of geosynchronous orbit satellite imaging sensor, the missile could be looked as if point target. When the spaced warning system search for point targets, noise of detector and background of cloud and atmosphere interfere the detection and tracking of point target heavily.in this paper, the characteristics of signal to noise of weak target will be analyzed by simulation technique of spaced imaging system. In addition, the imaging trajectory of missile will be researched as well. The main work can be divided into two parts:Firstly, employing MODTRAN model compute the radiance of circus and transmittance, and based on the result of missile plume radiance calculated by others, the IR scene of missile target and circus background is modeled. Then, a simulation system of IR imaging system was established, and warning images were outputted. By statists of simulated warning images, SNR curve could be obtained, and the range of warning system was provided.Secondly, according to dynamics model of missile powered phase, the missile trajectory could be solved. By imaging geometry, a model of conversion from 3D coordinate of earth to 2D focal plane coordinate of imaging system was established. On the foundation of this model, we studied the feature of trajectory of missile on the image, and focused on the offset error of trajectory because of satellite attitude disturbance. This job could contribute to the target detect, tracking and performance evaluation of warning system.This paper mainly aimed at research on target detecting SNR and characteristic of trajectory during the process of spaced warning system capturing and following missile target.