Adaptive PPN guidance law with impact angle constraint

In this work, two adaptive guidance law which achieve the specified impact angle are proposed. The first one is based on the conventional PPN guidance law, while the second one is inspired by controlling the turn rate of relative velocity. Since in both cases the analytical solutions of relative angles between target and missile velocity vectors are found, the proposed guidance laws do not require the estimation of time to go. In the meantime, the corresponding capture region with and without finite LOS turn rate constraint are also determined.