Finite-Time Convergence Guidance Law with Impact Angle Constraint in Active Aircraft Defense

In the case of active aircraft defense, the defending missile is used to intercept the attacking missile, for protecting the target aircraft. A defensive guidance law based on fast terminal sliding mode control is proposed to satisfy the terminal impact angle constraint, with the property of finite time convergence. The extended state observer (ESO) is designed to estimate the unknown attacking missile's acceleration, which reduces the chattering phenomenon. Simulation results demonstrate that the defending missile can hit the attacking missile in an expected impact angle by using the proposed guidance law.