Title: Optimal Sliding Mode Guidance for Interceptors with Impact Angle Constraint

In this paper a new guidance law, based on sliding mode control theory and applied parameter optimization method, is proposed, which can minimize control effort and adjust impact angle to predefined value. The optimal value of controller gains is achieved with PSO method. In order to satisfy intercept with target the parallel navigation idea has been used and for impact with desired angle a particular sliding variable has been introduced. Therefore the sliding variable is based on line of sight angle error and its angular rate. This sliding variable reaches to zero in finite time in the presence of uncertainties. Numerical simulations are presented to illustrate the potential of the proposed method.