Vehicle guidance system for guided missiles having adaptive trajectory bias

Method and apparatus are described for improving the impact angle between a missile and stationary or moving target in the presence of stationary or adverse wind conditions. A triggered bias detector provides an enabling signal to a bias resolver when the pitch line of sight rate of a missile exceeds a predetermined level. The bias resolver supplies first and second bias signals to the pitch forward guidance loop and yaw forward guidance loop in response to the detected pitch line of sight rate. The missile is given a lofting trajectory in response to the applied bias signal as it closes on the target. Impact angles of a more nearly vertical condition over a wide range of missile/target acquisition geometric conditions are obtained using this triggered bias technique over conventional constant gravity bias proportional guidance techniques.