An input output observer based guidance strategy for interceptor problem

The established guidance laws in literature are generally designed to capture the target while considering all the states of the interceptor model to be measurable. This paper demonstrates the use of an input output observer for the unmeasured state of the missile-target model with semi-global exponential results. A well-established guidance law called pure proportional navigation law is incorporated in this paper to demonstrate the application of the proposed observer. The missile’s angle of attack is the unmeasured state, which also appears non-linearly in the remaining two kinematic equations of the missile. The occurrence of the unmeasured state in the nonlinear form makes it more challenging to theoretically prove its convergence. The Lyapunov analysis is used to show the convergence of the observed state. Different scenarios consisting of the tail chase and head-on engagements with non-maneuvering and maneuvering targets are considered in the simulations to establish the effectiveness of the proposed guidance strategy.