Study On Control Strategy Of O-E Tracking Systems With Compound Axis

The laser weapon system requires not only tracking the moving targets in the field of view steadily ,but locking the beam on a certain point of the target. In general, it should track targets in the precision that is less than 1/3～1/5 of the angle of the expanded laser beam. Under such high precision, atmospheric overfall etc can not be ignored. Big inertia single-axis gimbals of ordinary optoelectronic tracking systems are impossible to have enough bandwidth to adjust it because of the limit of structural resonance frequency. So the compound-axis control system is introduced. Namely, to construct a main axis and sub-axis tracking mode with a fast steering mirror with high bandwidth mounted on big inertia single-axis gimbal. The sub-system can adjust the residual errors of the main system. So the high tracking precision of angular second can be obtained.The basic theories of the compound axis system are analysed , namely the reason why the compound axis system can promote the tracking precision, how the bandwidth ratio of the main system and sub-system affect the compound axis system. Through the analysis the conclusion that the subsystem will have more ability to adjust the residual errors of the main system with higher bandwidth ratio. Based on this conclusion, the main system and the subsystem is designed in the thesis.In the design of the main system, all kinds of random noise and their relationship with the bandwidth are analysed based on which the main system is designed. The new control strategy of using the equivalent compound control and on-axis control technology to reduce the output random noise of the main system while tracking the fast maneuvering object with the velocity of 30°/s and the acceleration of 10° /s~2 steadily with the tracking error less than 18' at the same time is introduced. Then the basic principle of the equivalent compound control system, on-axis tracking system and their key technology of predicting and filtering are introduced. The Kalman filter in the polar coordinates and it's related problems such as how to choose the state varieties and their starting values, the maneuvering model of the object, the statistic characters of the system noise and measurement noise, the stabilization of the...