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. The former can provide a miss distance between the A/C and the 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.