High Fidelity Real-time and Batch Simulation
The RAIF facility houses up to eleven dedicated simulation laboratories that are used for day-to-day flight research activities. Typical simulation tasks include: evaluation of new vehicle concepts, control law development and validation, flight safety analysis, mission planning, hardware-in-the-loop, aircraft-in-the-loop, flight envelope expansion, and post-flight data analysis.
The wide variety of flight research goals requires that the hardware used be highly configurable. To allow for this flexibility, each lab uses core technologies as a framework for each tailored solution. Every lab has its own isolated network to restrict unauthorized access to sensitive simulation data. Video projectors with large projection screens are used to display out-the-window, aircraft, and Heads-Up-Display (HUD) information. One lab features a 160-degree by 10 foot tall screen for use in situational awareness and formation flight research activities.
Commercial-off-the-shelf (COTS) hardware interfaces are used to provide input/output functions to fixed-based cockpits, flight hardware, or other special-purpose equipment. The fixed-based cockpits are usually accurate mockups of existing aircraft cockpits, but can be experimental one-of-a-kind as well. Analog instrumentation control and feedback is provided via an embedded controller that interfaces to the simulation through high-speed reflective memory. Flat panel touch-screen technology is provided as an alternative for instrument clusters where desired. Each cockpit is equipped with a Dryden developed electric stick and rudder pedal system. The Simulation Electric Stick (SES) system has highly configurable force, travel, and damping characteristics so that it can simulate the feel of many different aircraft. Each cockpit also provides a touch panel control. This intuitive single-user interface can be used from within the cockpit to command and control the simulation and access the simulation variables.
When the simulation needs to interface to flight hardware-in-the-loop (HIL) or aircraft-in-the-loop (AIL), the Dryden developed Hardware Interface Unit, or (HIU) is used. The HIU system provides modes to switch flight hardware in and out of the loop quickly, as well as simulate failure modes and effects on the hardware. Isolation and protection from the simulation is provided to prevent potential damage to one of a kind or expensive flight hardware. The HIU runs independent of the simulation through an embedded controller, and simulation control and feedback are provided via high speed reflective memory.
A versatile simulation software package has been developed for use in the RAIF simulations. All simulations are based on a Core software framework. The Core is a modular software framework that is extensible and easily configurable. This flexibility allows the same Core to be used on simulations ranging from gliders to suborbital vehicles and to run on platforms ranging from single-core computers to complex multiprocessor systems with several hardware interfaces while running pilot-in-the-loop or aircraft-in-the-loop simulations.
The Core is composed of standard models, mathematical routines, a user interface, hardware interfaces, timing routines, data recording and data input subsystems, external application interfaces, and other sharable modules. The core is written in the C++ programming language, but provides support for models written in a variety of languages. A Java™ graphical user interface (GUI) is used as the control interface for the simulation. This GUI provides an intuitive interface for accessing the many tools and features of the Core simulation, controls for manipulating the simulation models, test points, scripting tools and a simple fly-by-mouse interface with a HUD.
Batch mode allows the researcher an off-line version of the simulation that can be used from desktop computers for research activities that do not require real-time.
Each simulation provides an out-the-window view of the local area, and can provide a three-dimensional articulated model for display. This 3-D environment provides situational awareness for pilot mission training or alternative views for researchers.
The RAIF simulations can also drive the Dryden Range Mission Control Rooms with PCM streams generated by simulations. This capability is used to test control room displays, perform mission planning, train control room personnel for emergency procedures, and simulate a realistic control room environment to prepare for crucial test flights. The PCM streams generated by the simulation replicate what is down-linked by the actual aircraft in flight. Simulated data are also generated. A two-way communication link is provided for the pilot in the cockpit. Long-range optics and out-the-window scenes are simulated using the 3-D solid model graphics capability previously described.