Prescribed performance-based guidance law for impact-angle and impact-time control with field-of-view constraints

This study presents a homing guidance law based on a prescribed performance controller (PPC) to simultaneously satisfy impact-angle and impact-time constraints. The proposed approach leverages a range-parametrized prescribed performance function (PPF) designed to be continuous and smoothly differentiable to enforce the impact-angle constraint. For the impact-time constraint, a closed-form expression for the time-to-go is first derived by modeling the line-of-sight angle as a polynomial function of the range. The resulting time-to-go error dynamics are then enforced through the designed PPF, whose bounds dynamically contract with the remaining range to ensure error convergence to the prescribed terminal bounds. The field-of-view constraint is enforced through a smooth switching function in the integrated guidance law, ensuring that the look-angle remains within its prescribed limits. Extensive numerical simulations validate the effectiveness of the proposed approach.