Method and apparatus for intercepting an evading target alerted at seeker turn-on

A method and apparatus for directing a pursuing vehicle, such as a torpedo, on an intercept trajectory from a launching vehicle to a target vehicle with evasion capabilities and the target vehicle is alerted to pursuing vehicle at the time that the pursuing vehicle enables its seeker. Models of the pursuing vehicle and evading target provide proposed trajectories based upon various environmental considerations. A guidance system uses estimates of initial operating parameter solutions for the pursuing vehicle, such as gyro angle, intercept time and run-to-enable time, to begin a convergent, iterative process that defines final operating parameter solutions from which the guidance parameters are determined and transferred to the pursuing vehicle at launch.