Estimation enhancement by cooperatively imposing relative intercept angles

Cooperative estimation/guidance for a team of missiles is the topic of this paper. An example scenario is considered where an aircraft simultaneously launches several cooperative defending missiles as a countermeasure against an attacking homing missile. A new reduced-order estimation scheme based on information sharing to cooperatively estimate the relative states and the unknown parameters of the attacking missile is proposed. Each defending missile shares its own noise-corrupted line-of-sight angle measurement with the rest of the team. The observability of this multi-line-of-sight measuring environment is enhanced by cooperatively imposing nonnegative relative intercept angles between consecutive defenders. The ability of the proposed strategy to protect the targeted aircraft is studied for a two-defender case via extensive Monte Carlo simulations. The effect of different values of the commanded relative intercept angle on the pure estimation as well as on the intertwined guidance-estimation performance is carefully analyzed for various considerations of the defenders' maneuverability.