Feasible Initial Conditions for Bias Proportional Navigation Guidance Laws Under Look Angle Constraints

This study examines the conditions for guaranteeing stationary target interception without violating the impact angle and the look angle limit constraints during flight. Two types of new guidance laws are proposed for the constrained guidance problem in the form of a bias proportional navigation based on linear and nonlinear impact angle error feedback. Unlike the relevant previous study, both the range and the look angle are considered as the scheduling variables of the shaping functions, assuming that a constant stream of reliable range information is available. Also, the proposed guidance laws does not involve any explicit command switching. The set of feasible initial conditions are determined by the sufficient condition for guaranteeing constraint satisfaction during the entire time interval. The proposed sufficient condition can be thought of as the quantification of the set of feasible launch conditions with the desired final impact angle fixed, or vice versa.