Pasif Torpido Güdümü İçin Yeni Bir Yöntem
Torpedoes are ammunition that have active or passive seekers. Passive target tracking methods should be used to track targets with torpedo that has passive seeker. Kalman filter is the one of the most commonly used methods in target tracking. The dynamic model used in the linear Kalman filter must also be linear. In the passive target tracking, since the dynamic model used is not linear, different variants of Kalman filter or different approaches are used. Which point of view that passive seekers tracks the target from is important in terms of tracking. One of the factors that determine the quality of target tracking is the torpedo - target geometry. The proportional navigation guidance that used in torpedo guidance requires torpedo – target closing velocity. Torpedoes cannot obtain this information through the passive seeker. Therefore, an average closing velocity is generally used in the guidance algorithm. This guidance approach can change the performance of the torpedo according to what side of the target that torpedo is fired from. In this study, two different passive target tracking methods, namely Extended Kalman Filter and Pseudo Measurement Kalman Filter, are investigated. Passive target tracking is performed by using these two different methods. Simulations are made with different scenarios and different measurement geometry are obtained by the torpedo that is instantly exposed to different maneuvers. The measurement angle which will provide the best quality tracking is tried to find by a recursive method with these simulations. The acceleration that provides the found measurement angle and the acceleration that provides the proportional navigation guidance are merged by coefficient function and the ultimate demanded acceleration is calculated. Target state variables are estimated and the torpedo guidance to the target is provided by performing passive target tracking with ultimate demanded acceleration at the same time. Closing velocity is calculated from estimated target velocity by using torpedo – target geometry. The calculated closing velocity and average closing velocity are given as input to the proportional navigation guidance and performance analyzes are performed on different scenarios. In order to make the scenarios more realistic, the passive seeker gimbal angles are limited and the torpedo guidance is terminated at a remaining certain distance to the target. Thus, in more realistic scenarios, it is tried to understand how effective the estimated closing velocity is on proportional navigation guidance and the torpedo performance.