Boost Phase Plume-to-Hardbody Handover
Small Business Information
100 Wall Street, Princeton, NJ, 08540
AbstractSeveral plume-hardbody handover algorithms under development are demonstrating capability to localize the missile body when the body is resolved or approximately the size of a pixel. Several scenarios involving liquid propellant missile systems, such as those involving large angles of attack and those observed at moderate to long ranges and near nose-on viewing aspect angles, provide challenges to both single and dual band infrared concepts. Since wavebands are typically optimized for plume detection, these conditions challenge space-based and airborne systems employed to provide accurate metrics for reconstruction of threat trajectories and to provide position information for midcourse intercept within the BMDS. In the enhancement flight regime (typically 70-200 km altitude for ICBM class missiles), fluid dynamic considerations indicate that plume radiance patterns exhibit a characteristic parabolic shape. This parabola is maintained even at large angles of attack, when the windward side of the plume may be significantly brighter than the leeward side or the localized "vacuum core" region used as an aim-point for certain handover algorithms. Fitting the radiance pattern to this characteristic parabola provides a means to determine the plume symmetry axis. Relatively straightforward interpretation of the radiance patterns, possibly augmented with off-board information or information gained from multiple frames of data, yields features that determine whether the threat is observed at near nose-on aspect angles or high angles of attack. These features can then be used to select the correct "bright point" that includes the missile body. Moreover, this parabola provides additional information revealing characteristics of the propulsion system for purposes of target identification. In our Phase II studies we will refine the algorithms developed in Phase I for measuring and exploiting this parabolic shape of the plume.
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