抄録
Every homing missile guided by proportional navigation guidance (PNG) has a seeker to detect the line-of-sight (LOS) angle rate, which is essentially needed for PNG. But, this seeker also has the property of imperfect-gimbals-stabilization (IGS) that can lead to guidance instability. In this report, essential two types of the seeker, namely free-gyro-type and rate-gyro-type are given in the form of block diagram at first, then, 1) a missile guidance & control (G&C) system with seeker IGS is shown, which reveals the existence of a new parasitic loop in the G&C system; 2) a sufficient stability condition of the parasitic loop is derived by small gain theorem; 3) this condition is simplified by classical shaping method; 4) at the same time, the steady state error in acceleration control system is pointed out in the case of free-gyro-type seeker; 5) and finally, the results of 3) and 4) are confirmed numerically by MATLAB simulation.
