Prediction of Time-to-Go for a Homing Missile Using Bang-Bang Control

Abstract : The flight time required for a variable-speed homing missile to intercept a zero-acceleration target in two dimensions is determined by assuming that the missile normal acceleration is bang-bang, that is, maximum normal acceleration followed by zero normal acceleration where the switch time which gives intercept is to be determined. For those cases where intercept does not occur in a reasonable time, the flight time which minimizes the miss distance is used. A tangential acceleration profile is assumed for the missile, so that the velocity of the missile becomes a known function of time, and the equations of motion can be solved analytically. Then, an algebraic equation for the switch time for intercept or the final time for closest approach can be derived, but it must be solved numerically. Results show that this time-to-go algorithm improves the performance (miss distance) of the missile for several scenarios relative to the range-over-closing-speed algorithm.