Strapdown Antenna Platform Stability Study

The seeker is a target-track device which is installed on the missile. However, seeker's line of sight (LOS) is always inevitably influenced by various factors in tracking process so that the tracking effect will be discounted largely. We must use stable platform to make the LOS stable. When comes to this problem, dynamically tuned gyroscope, as well as rate gyroscope, is usually applied in conventional plan. But when smaller radar seeker is concerned, the conventional gyros platform is inapplicable for its large bulk. Because of this, this paper studies the half-strapdown plan that probably suitable to solve the problem.Firstly, based on the configuration features of two-degree-of-freedom half-strapdown antenna platform, this paper builds its dynamics models. Besides, the gimbal coupling and missile coupling characteristics are simulated and analyzed in computer to find out its influences to the seeker's LOS. And then, we can say that half-strapdown plan is suitable to solve the problem. After that, the paper presents the block diagrams of half-strapdown antenna platform control system, builds the transfer functions of controlled object, deduces two kinds of stabilization algorithms-angle algorithm and angle-rate algorithm in detail. Finally, the paper fixes optimal coefficients and PID parameters, offers appropriate compensating functions. At last, the seeker's LOS rates are limited between satisfactory scopes.The results of my paper's study are that, half-strapdown stable plan can be applied in smaller radar seeker. The LOS rates of the antenna are influenced mainly by missile's motion. But, we can use both of the two algorithms to separate missile's influences. And the results of computer simulation indicated that the angle-rate algorithm is a little better than angle algorithm in steady error control.