Release Point Determination and Dispersion Reduction for Ballistic Airdrops

Abstract

Physics based models for all phases of an airdrop are presented. These models can be used in conjunction with near real-time wind measurements to optimize an air release point for multi-package bundles in high-altitude low-opening (HALO) airdrops with ballistic drogue and main parachutes. In addition to using the predictive capability of the models to select optimal release points for minimum miss distance, several methods are presented that can reduce multi-package impact dispersion. Variations in a derived wind drift coefficient, which relates the inertial properties of each package to its aerodynamic characteristics, are shown to result in significant dispersion in winds with non-constant direction. Mitigation of this effect through manipulation of the bundle mass or aerodynamic properties is proposed in conjunction with a simulation based aircraft heading and package release order optimization to minimize the overall impact dispersion. Additional optimizations are used to select main parachute deployment altitudes for each package to further reduce the airdrop dispersion. The methods presented are designed to be suitable for real-time implementation on a mobile computer that monitors aircraft flight and wind data and interfaces with ballistic parachute systems. ∗UAS Controls Engineer, Autonomous Control Branch, Power and Control Division, Aerospace Systems Directorate, 2210 Eighth Street, Room 300, Email josiah.vandermey@gmail.com †Principal Aerospace Engineer, Autonomous Control Branch, Power and Control Division, Aerospace Systems Directorate, 2210 Eighth Street, Ste. 21, Email david.doman@us.af.mil, Ph. (937) 713-7003, Fellow AIAA ‡Research Engineer, 1270 North Fairfield Road, Email adam.gerlach.ctr@us.af.mil, Ph. (937) 713-7040