Advances in computer technology have allowed Army engineers and scientists to make increasing use of models and simulations and save money. When hardware procurement is eliminated because the needed information can be obtained through simulation, both time and money are saved. In addition, environmental impacts such as noise and pollutants generated during physical trial and error evaluation are eliminated. The following sections discuss computer M&S, software technology, physical simulation, hardwareintheloop simulation, combined arms battlefield soldierintheloop simulation, and T&E simulation.
1. Computer Modeling and Simulation
Computer M&S can generate images of complex data and evaluate experimental conditions and approaches. Visualization techniques used with complex modeling permit scientists and engineers to exploit new concepts without the development of costly prototypes. Computer M&S is applicable to a wide range of technical disciplines as illustrated below.
Human Factors Modeling. ARLs human performance model program uses JACK, a 3D model developed by the University of Pennsylvania (Figure VI14). JACK is used in the Aviation RDECs A31 (ArmyNASA Aircrew/Aircraft Integration) program aimed at producing software tools and methods to improve the human engineering design process for advanced technology crew stations. This approach allows variations of mission procedures and cockpit equipment to be explored rapidly prior to committing a design to an expensive hardware simulator.
Armor and Projectile Modeling. Highspeed, large memory supercomputers have greatly enhanced our capabilities in modeling new armor concepts and advanced projectile technology. Recent largescale simulations have provided insight into the potential benefits of advanced highvelocity projectiles. Figure VI15 illustrates one penetrator concept. The penetrator is composed of a train of segments supported in a carrier tube. The trainofsegments model is a laboratory version of a segmented projectile that may have merit for use in future armor systems.
Figure VI-15. Computer Simulations.
Computer simulations of device design and operation can be used instead of costly prototyping and field tests. The comparison shows the accuracy with which computer simulations can reflect the physical world.
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Environmental Modeling. Army tactical operations must take into account their environments. Digital terrain information and atmospheric information are used in wargames and simulations to determine the outcome of tactics changes and new equipment introductions. Climate databases provide realism by projecting different weather conditions into a simulated theater of operations. Weapon systems are evaluated for effectiveness, taking into consideration target detection probabilities based on climate and terrain masking.
Weapons and Fire Control Modeling. ARDEC at Picatinny Arsenal, New Jersey, has established a DIS node to determine and show how technology, weapons, and weapon mixes can be used to maximize the effectiveness of the soldier.
2. Software Technology
DARPA is the sponsor of the Software Technology for Adaptable, Reliable Systems (STARS) program to increase software productivity, reliability, and quality through the adoption of a new software engineering paradigm called megaprogramming.
STARS is sponsoring megaprogramming demonstration projects on DoD systems within each of the services. These demonstration projects help quantify the benefits of the megaprogramming paradigm and the issues involved in transitioning to this new paradigm.
The CommunicationsElectronics Research, Development, and Engineering Center (CERDEC) has developed the STARS Laboratory to support the development of domain models and architectures and reusable assets. The software engineering environment is also used to reengineer C4I weapon system software to include the integration of domain architectures and assets in the application software.
3. Physical Simulation
Physical simulations are used today in Army research to emulate realtime physical motions of active systems in the field. In many situations, computergenerated models and simulation systems can interact with physical simulations to greatly reduce the need for costly and timeconsuming field tests of prototypes. Following are examples of advanced physical simulation facilities operated with computergenerated models or simulation systems.
The crew station/turret motion base simulator (CS/TMBS) is a full sixdegreesoffreedom (DOF) laboratory simulator with highperformance capabilities. It can impart a maximum of 6 g acceleration to a heavy combat vehicle turret weighing up to 25 tons and replicate, via computer control, motions/vibrations that would be encountered while traveling over rough crosscountry terrain. This simulator at TARDEC is manrated and approved for occupancy by a crew. The CS/TMBS plays an important role in turret system development, characterization, and virtual prototyping activities in a variety of combat vehicle programs. The operation of different azimuth drive motors in a Bradley fighting vehicle turret is shown in Figure VI16.
Among the advantages of manintheloop tests in the laboratory are close control of parameters and exact repeatability of tests for comparing the effect of different components.
The Aviation RDEC CrewStation Research and Development Facility (CSRDF) supports the evaluation of new concepts for humansystem interactions for advanced rotorcraft. Effects of malfunctions, automation alternatives, and mission equipment tradeoffs can be conducted in this synthetic environment of 3D visuals, sounds, and tactile stimuli (Figure VI17). The degree of realism achieved in such systems can best be appreciated by seeing a pilot emerge from a laboratory "flight" showing perspiration and other signs of stress. The CSRDF is used extensively to support the Rotorcraft Pilots Associate ATD and is one of the primary simulators used to validate DIS protocols and the BDSD program. The aviation testbed at Fort Rucker and the CSRDF have been linked to support Force XXI objectives and are being extended to include TankAutomotive and Armaments Command (TACOM), lineofsight antitank (LOSAT), and Sikorsky Comanche simulators.
Another example is the simulator training advanced testbed for aviation (STRATA). Through a cooperative agreement with the Government of Canada, the Army Research Institute (ARI) developed the STRATA research simulator to examine the full range of training device and flight simulator training strategies and tradeoffs and design requirements for future lowcost simulators. STRATA is a dedicated research facility at ARIs Fort Rucker field unit for aviation training research. STRATA permits rapid reconfiguration to emulate training devices with different visual displays, cockpit configurations, aerodynamic models, etc. STRATA will enable the Army to empirically determine the most effective training strategies using an affordable mix of live exercises and existing training aids, devices, simulations, and simulators for initial flight skills.
CECOMs Night Vision and Electronic Sensors Directorate has developed a facility to support the development and testing of integrated aircraft and ground vehicle sensors and countermeasures. The multispectral environmental generator and chamber (MSEG&C) provides 360degree radar frequency, laser, infrared, and ultraviolet simulation of air defense radars, surfacetoair missiles (SAMs), topattack/smart munitions, and laser threats. Varied individual and integrated protection equipment is used to simulate ground vehicle and aircraft attitudes. The equipment is instrumented and placed on a computercontrolled table in the center of an anechoic chamber (Figure VI18).
Figure VI-18. Multispectral Environmental Generator and Chamber
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