NEAR-OPTIMAL 3-DIMENSIONAL AIR-TO-AIR MISSILE GUIDANCE AGAINST MANEUVERING TARGET

Closed-loop guidance of a medium-range air-to-air missile (AAM) agains t a maneuvering target is synthesized using a three phase, near-optima l guidance scheme. A targe period of the closed-loop guidance is perfo rmed using neighboring optimal control techniques about open-loop opti mal solutions obtained by solving the associated minimum time to inter cept trajectories. The first phase is the boost phase guidance where t he normal acceleration limit may be active due to high lofting of the boost-sustain-coast AAM. The guidance in this phase accommodates only errors in the missile's state variables, the target maneuvering being neglected. The boost phase guidance involves guidance in the presence of active control constraints. The second phase is the midcourse guida nce where both state perturbations and target maneuvers are considered . Comparisons are made between guidance with gain indexing performed w ith clock time and with performance index to go. Models of aggressive target and run-away targets were used and the guidance scheme performa nce is excellent. Three methods of optimal gain evaluation are also di scussed. Performance augmentation is obtained by using a center of att ainability as a pseudotarget that fairs into the actual target as time to go becomes zero. The final phase is the terminal guidance, which e mploys proportional navigation and its variants.