Studies in Trajectory Tracking and launch Point Determination for Ballistic Missile Defense

摘要

Detecting and localizing a threat ballistic missile as quickly and accurately as possible are key ingredients required to engage the missile during boost phase over the territory of the aggressor, and rapid and accurate launch point determination is crucial to attack hostile facilities. Earlier research has focused on track initiation, boost phase tracking and rapid launch point determination using augmented IMM and Kalman-based techniques. This work extends that earlier research by comparing these IMM and Kalman-based trackers and backfitters with the newer particle filters to see what advantages particle filters might offer in this application. Simulations used in this research assume the ballistic missile target is in boost phase, transitioning to coast phase using a gravity turn and constant gravity. The rocket is assumed to be single stage. The IMM tracker performs well in tracking through booster cutoff. A smoothed estimate of the initial target state vector is used to backfit for launch point determination. Errors in this process are rather large and there appear to be biases in the estimates. These results are compared with a particle filter implementation. Here the correct nonlinear model of the missile dynamics was used, but the algorithm had to estimate engine thrust and the drag coefficient as well as position and velocity states. This algorithm proved to be a large disappointment because the number of particles required to generate reasonable results was large and the algorithm run time became unrealistically long.