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Andrews AFB, United States

McGrath B.E.,Aerospace Systems Design Group | Cybyk B.Z.,APLs | Frey T.M.,Awareness and Response Information Systems Group
Johns Hopkins APL Technical Digest (Applied Physics Laboratory)

Existing unmanned aerial system (UAS) platforms do not perform well in environments with complex terrain and highly variable aerodynamics. However, it is essential that the warfighter operate UASs in such complex environments (e.g., urban areas, canyons, and mountains). Thus, a need exists for a high-fidelity, physics-based modeling and simulation framework addressing this parameter space. The APL UAS mission planning and simulation tool provides the framework to perform environment-vehicle interaction studies. The framework includes computational fluid dynamics modeling of the complex terrain airflows, vehicle aerodynamics and dynamics models, terrain models, and a visualization engine. This article focuses on development, formulation, and implementation, within this framework, of environment-vehicle interaction models for UAS operations in complex environments. Results for implementation of one environment-vehicle interaction model show the effects on the trajectory (e.g., latitude, longitude, altitude, vehicle attitude, vehicle rates, and autopilot control commands). Examination of such results helps understand the effects of these interaction models in the context of validated terrain airflow models in realistic complex environments. The APL UAS mission planning and simulation tool provides a compelling synthetic environment in which to perform these environment-vehicle interaction studies that includes relevant operational constraints to increase the probability of mission success for UAS operations in these complex environments. Source

Funk B.K.,Targeting Systems Group | Bamberger R.J.,Robotics and Autonomous Systems Group | Barton J.D.,FPDs Weapon and Targeting Systems Group | Carr A.K.,APL | And 5 more authors.
Johns Hopkins APL Technical Digest (Applied Physics Laboratory)

The DoD has a mission need to engage moving targets in an urban setting in clear and adverse weather conditions. To address this mission need and overcome the limitations associated with conventional airborne targeting and weapon platforms, APL embarked on an independent research and development (IR&D) effort to weaponize a small unmanned aerial system (UAS) that is capable of cooperating with currently fielded small UASs to execute the entire kill chain (find, fix, track, target, engage, and assess). The main objectives of the IR&D effort were to plan a mission using a UAS simulation environment, demonstrate the enabling technologies that would allow a group of cooperating small UASs to execute the entire kill chain in a complex aerodynamic environment, and demonstrate the lethality of a small UAS-compatible warhead. The accomplishment of these IR&D objectives led to a successful demonstration of the cooperative hunter/killer UAS concept performing convoy protection at the Joint Expeditionary Forces Experiment 2010 (JEFX 10) at the Nevada Test and Training Range. Source

Popkin S.H.,Aerospace Systems Design Group | Taylor T.M.,Aerospace Systems Design Group | Cybyk B.Z.,Aerospace Systems Design Group
Johns Hopkins APL Technical Digest (Applied Physics Laboratory)

Active flow control, a field dedicated to developing techniques to improve vehicle performance characteristics through local flow manipulation, has successfully generated several devices capable of controlling low-speed, subsonic flows. However, the availability of analogous devices or techniques for high-speed, supersonic flows is limited. A promising plasmadynamic device, the SparkJet actuator, is being developed at APL under Air Force Office of Scientific Research sponsorship. In collaboration with Florida State University and the Air Force Research Laboratory, priority applications will include, but are not limited to, mitigating unsteady pressure waves in open supersonic bomb bay cavities and reducing flow separation on low-pressure turbine blades to improve turbojet efficiency. After an introduction to targeted applications for the SparkJet, this article will describe the experimental and numerical modeling techniques, including recent supersonic wind tunnel tests, used to evaluate SparkJet performance, the conclusions drawn from these techniques, and the challenges associated with evaluating SparkJet performance. © 2013 The Johns Hopkins University Applied Physics Laboratory LLC. Source

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