Missile Threat Detection and Evasion Maneuvers With Countermeasures for a Low-Altitude Aircraft

This article investigates man-portable air defense systems (MANPAD) missile threat detection and an effective maneuvering strategy for aircraft (A/C) destruction avoidance. The 3-D trajectory of a multistage missile (boost and sustain phases) under pure proportional navigation is first estimated. The maximum likelihood estimator is used to estimate its motion parameters of the two-stage missile considered using only angle measurements from a low-altitude A/C. Missile threat detection is investigated based on two methods: 1) estimation-based as a baseline method and 2)threat-plane-based. Theformer can provide a miss distance betweenthe A/C andthe missile, but more measurements are required. The latter is shown to give a faster threat alert, allowing the A/C to start the evasive maneuver earlier. An efficient evasion maneuver for avoiding destruction is banking away from the missile by a turning maneuver in the horizontal plane due to its low altitude. The survivability probability of the A/C is evaluated with and without countermeasures (flares). There are two key factors that affect the evasion performance: 1) maneuver start time and 2) the maximum acceleration during the maneuver. Simulations show that the A/C can start maneuvering earlier using the threat-plane-based method compared with the estimation-based method. It can successfully evade the missile with the help of maneuvering. It is also shown that using flares, the necessary maneuver is less drastic (lower g s). Simulation results compare the necessary g s for obtaining a certain minimal distance from the missile.