Advances in computer technology have allowed Army engineers and scientists to make increasing use of models and simulations. Their use has resulted in substantial savings. One area where costs have been cut is contracting. 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 (a) Computer Modeling and Simulation, (b) Software Technology, (c) Physical Simulation, (d) Hardware-in-the-Loop Simulation, (e) Combined Arms Battlefield Soldier-in-the-Loop Simulation, and (f) Test and Evaluation Simulation.
a. Computer Modeling and Simulation
Computer simulation and modeling can be used to evaluate experimental conditions and approaches and generate images of complex data. Visualization techniques used with complex modeling permit scientists and engineers to exploit new concepts without the development of costly prototypes and enable visual images to be developed without resorting to photographs or artists' concepts. Computer simulation and modeling is applicable to a wide range of technical disciplines as the following examples show.
Human factors modeling
An example of ongoing research is the development of a human performance model for simulating the interactions among operators, tasks, equipment, and their operating environments. The Army Research Laboratory Human Performance Model Program uses "JACK," a three-dimensional computer-aided design human figure model developed by the University of Pennsylvania (see Figure VI-14).
Figure VI-14. "JACK," a 3-D computer-aided design human figure model, is used to evaluate soldier interactions with weapon system design concepts.
An example of the use of JACK is the Aviation RDEC's A31 (Army-NASA Aircrew/Aircraft Integration) Program, an exploratory effort aimed at producing software tools and methods to improve the human engineering design process for advanced technology crew stations. The program's basic approach is to embed models and principles of performance (e.g., vision, memory, decision making, and anthropometry) into a computer-aided design system. The resulting tool, called the Man-Machine Integration Design and Analysis System (MIDAS), supports "what if" analyses concerning the entire range of human engineering design concerns. Through MIDAS, a computer simulation is produced in which human performance models attempt to accomplish their prescribed tasks within a user-specified mission context and cockpit configuration. This approach allows variations of mission procedures and cockpit equipment to be explored rapidly, prior to committing a design to an expensive hardware simulator where more detailed human-in-the-loop analyses are performed.
Armor and projectile modeling
High-speed supercomputers with large memories have greatly enhanced our capabilities in modeling new armor concepts and advanced projectile technology.
Recent large-scale simulations have provided insight into the potential benefits of advanced high-velocity projectiles. Figure VI-15 illustrates one penetrator concept. The penetrator is composed of a train of segments supported in a carrier tube. The train-of-segments model is a laboratory version of a segmented projectile that may have merit for use in future armor systems.
Figure VI-15. 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. Top: experimental projectile flight; bottom: simulated projectile flight.
Click here to view enlarged version of image
Army tactical operations must take into account the environment in which they take place. Terrain information provided in digital form and atmospheric information about the planetary boundary layer which provides an understanding of the dynamics of wind, relative humidity, temperature, and turbulence fields over complex terrain are employed in wargames and simulations to determine the outcome of tactics changes and new equipment introductions. Climate data bases 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
The Armament Research, Development, and Engineering Center (ARDEC) at Picatinny Arsenal, New Jersey, has established a DIS Node for the purpose of determining and presenting how technology, weapons, and weapons mixes can be used to maximize the effectiveness of the soldier. A "core" capability exists which is sufficiently flexible to support varied simulation requirements. Further, ARDEC is in the process of developing system upgrades to add capability for engineering level analysis. The purpose is to simulate before bending metal.
b. Software Technology
DARPA is the sponsor of the Software Technology for Adaptable, Reliable Systems (STARS) Program, whose goal is to increase software productivity, reliability, and quality through the adoption of a new software engineering paradigm called megaprogramming. Megaprogramming is based on modern software development processes and the domain-specific software architecture and reuse concepts integrated with state-of-the-art software engineering environment.
As part of the STARS strategy to accelerate the shift within the DoD to the megaprogramming paradigm, STARS is sponsoring megaprogramming demonstration projects on actual DoD systems within each of the Services. These demonstration projects will help quantify the benefits of the megaprogramming paradigm and the issues involved in transitioning to this new paradigm.
In conjunction with the Army's STARS demonstration project, CERDEC has developed the STARS Laboratory. This laboratory provides support for the development of domain models, domain 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.
At the completion of the STARS projects, CECOM will have a modern, state-of-the-art software support environment that sustains the megaprogramming concepts and is tailorable to various domains and projects. The integrated tool set and processes will significantly reduce cost and improve the productivity and quality of future software-intensive Army projects.
c. Physical Simulation
Laboratory physical simulations are used today in Army research to emulate real-time physical motions of active systems in the field. In many situations, computer-generated models and simulation systems can interact with physical simulations to greatly reduce the need for costly and time-consuming field tests of prototypes.
Following are examples of advanced physical simulation facilities operated with computer-generated models and/or simulation systems.
The Crew Station/Turret Motion Base Simulator (CS/TMBS) is a full six degrees of freedom laboratory simulator which has uniquely high performance capabilities. It can impart a maximum of 6g acceleration to a heavy combat vehicle turret weighing up to 25 tons and replicate, via computer control, actual motions/vibrations that would be encountered while traveling over rough cross-country terrain represented in the computerized databank.
This simulator, located at TARDEC, is man-rated 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.
Several series of laboratory tests have already been completed using this simulator, including the testing of an experimental turret designed and built by the General Dynamics Company and the operation of different azimuth drive motors in a Bradley Fighting Vehicle Turret (see Figure VI-16).
Figure VI-16. The Crew/Station/Turret Motion Base Simulator (CS/TMBS) allows new vehicle turret designs to experience real-world operational environments in a controlled laboratory setting.
There are several significant advantages of being able to conduct man-in-the-loop tests in the laboratory. Foremost of these is close control of the influential parameters and exact repeatability of tests for comparing the effect of different components.
TARDEC has received and is installing an exciting propulsion test capability called Power and Inertia Simulator (PASI). This advanced dynamometer system uses mathematical expression to cause this electric motor-generator dynamometer system to replicate dynamic conditions such as national/tanslational inertia, wind, and slope. On the PASI, true operational profiles can be simulated.
The Aviation RDEC Crew-Station Research and Development Facility (CSRDF) supports the evaluation of new concepts for human-system interactions for advanced rotorcraft. Effects of malfunctions, automation alternatives, and mission equipment tradeoffs can be conducted in this synthetic environment of 3-D visuals, sounds, and tactile stimuli (Figure VI-17). 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 will be used extensively to support the Rotorcraft Pilot's Associate Advanced Technology Demonstration and is one of the primary simulators used to validate DIS protocols and the BDS-D program. The Aviation Test Bed at Fort Rucker and the CSRDF have already been linked to support FORCE XXI objectives. This linkage is being extended to include TACOM, LOSAT, and the Sikorsky Comanche Simulators.
Figure VI-17. Innovative rotorcraft technologies are evaluated for operational compatibility in the rotorcraft simulator facility.
Another example is the Simulator Training Advanced Test Bed for Aviation (STRATA). Through a cooperative agreement with the Government of Canada, the Army Research Institute (ARI) for the Behavioral and Social Sciences 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 low-cost simulators. STRATA is a dedicated research facility at ARI's Fort Rucker, Alabama, field unit for aviation training research. The modular design of STRATA permits rapid reconfiguration to emulate training devices with different visual displays, cockpit configurations, aerodynamic models, tactical threat sophistication, motion cueing, and visual data base detail. The use of 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 for individuals through unit combat tasks.
The Construction Engineering Research Laboratory (CERL) of the Corps of Engineers operates a Heating, Ventilating, and Air Conditioning Facility (HVAC) to provide a place to study and experiment with building environmental control systems. The Facility was constructed with a grant from the Department of Energy and has seven distinct sections: (1) ventilation, (2) hot water supply loops, (3) chilled water supply loops, (4) four zones, (5) HVAC system configuration, (6) facility controls, and (7) data acquisition. The test facility is used on a continuing basis to aid in the improvement of HVAC systems and controls used in military buildings in the quest for reduction in the cost of facility operation.
CECOM's Night Vision and Electronic Sensors Directorate Survivability Integration Laboratory has developed a facility to support the development and testing of integrated aircraft and ground vehicle sensors and countermeasures. The Multi-Spectral Environmental Generator and Chamber (MSEG&C) provides 360 degree radar frequency, laser, infrared, and ultra-violet simulation of air defense radars, surface-to-air missiles (SAMs), top attack/ smart munitions, and laser threats. Various individual and integrated protection equipment is used to simulate ground vehicle and aircraft attitudes as the vehicle is artificially moved through the threat environment. The equipment is instrumented and placed on a computer-controlled table in the center of an anechoic chamber (Figure VI-18). New threat simulators are being added to support the Hit Avoidance ATD, distributed interactive simulation with Fort Rucker and Fort Knox, the Rotorcraft Pilot's Associate ATD, and PEO customers.
Figure VI-18. Multispectral Environmental Generator and Chamber
CECOM's Space and Terrestrial Communications Directorate has a facility to incorporate the realistic effects of C3I/EW models. The S&T Modeling and Simulation facility houses a large assortment of network models and tools to develop, run, and analyze complex simulations; to obtain information on network/system throughput traffic distribution; delays/response times; and overall performance. Two distributed interactive simulation network terminals are being added, which will be interconnected to other DIS facilities via Army Interoperability network circuits.
d. Hardware-in-the-Loop Simulation
Hardware-in-the-loop simulation, which tests various types of systems using a combination of actual hardware and computer simulations, provides a significant return on investment for the Army.
One example of hardware-in-the-loop simulation is ARDEC's Ware Simulation Center located at Rock Island Arsenal, Illinois (Figure VI-19). This physical simulator is used to provide a realistic emulation of the field environment that the armament system will encounter. The facility can test weapons using up to 30mm live or 40mm inert ammunition. In addition, the facility's six degrees of freedom simulator is a large mount capable of holding weapons, gun turrets, and vehicle sections weighing up to 10,000 pounds and measuring up to 8.1 feet high. Programmed vibrations as well as pitch and yaw motions may be applied to the attached loads while its weapons are test fired in the indoor range. The combination of a large motion simulator situated in an indoor firing range provides a unique opportunity to test armament systems under controlled conditions.
Figure VI-19. The Ware Simulation Center's Six-DOF mount allows conceptual and fielded weapons to be fired in realistic mounting environments to isolate design deficiencies in controlled laboratory conditions.
Another example of hardware-in-the-loop simulation is the AMCOM Open-Loop Tracking Complex (OLTC), a computer-automated electro-optical countermeasure (EOCM) simulation facility that provides electronic warfare analysts the tools for evaluating the performance and effectiveness of electro-optical air defense missile systems and guidance assembly hardware in the presence of countermeasures. The facility allows for the performance verification of a missile guidance assembly before firing, permits the verification of missile performance under countermeasure environments in preparation for live-fire programs, and permits the discovery of missile system weaknesses throughout the development and acquisition phase of the missile.
These types of systems provide the highest level of simulation sophistication available, permitting hundreds of simulated "flights" to be made safely, at a cost significantly less than the cost of a single flight test. Simulated flights can be exercised in a secure environment to explore system vulnerabilities and capabilities against threats and countermeasures that do not lend themselves to free space testing.
CECOM has implemented the Army Interoperability Network (AIN), a nationwide suite of distributed communications capabilities and services to support interoperability and software development for Army C4I systems throughout their life cycle. The AIN provides the Army infrastructure for C4I systems to achieve the objectives of the Army Enterprise Strategy, i.e., Battlefield Digitization and C4I for the Warrior. The AIN provides rapid engineering support solutions that replicate battlefield configurations by networking dispersed fielded C4I systems. Current AIN major operational equipment now includes the AIN Central Control Facility; Protocol Assessment Facility; four sites at Fort Monmouth; and remote sites at Fort Leavenworth, Fort Sill, and Fort Huachuca. A remote site is planned for PEO Armored Systems Modernization at General Dynamics Land Systems, Warren, Michigan. A transportable AIN node is available to provide a quick-reaction AIN access in situations requiring rapid test support. The AIN is the Army's infrastructure for linking the Battle Labs with the RDECs.
e. Combined Arms Battlefield Soldier-in-the-Loop Simulation
Enhanced design architectures and improved battlefield simulation techniques are rapidly growing areas of Army simulation and modeling capability. The Army leadership has a vision of how the totality of battlefield simulation technology and techniques can be used throughout the research and acquisition process (see Figure VI-20).
Figure VI-20. Potential Use of Battlefield Simulations Throughout the Research and Acquisition Process
Click here to view enlarged version of image
The cornerstone of the Army vision is the BDS-D program, a long-term project with the ultimate objective of creating and maintaining a distributed, state-of-the-art network capability linking government, university, and industry sites into a simulation of the combined and joint arms battlefield. The BDS-D program is delineated in Figure VI-11 and the surrounding text.
This distributed interactive simulation capability builds on the continued growth and development of the DARPA-sponsored SIMNET technology, currently the basis for Army simulation test bed facilities at Fort Knox, Kentucky; Fort Benning, Georgia; and Fort Rucker, Alabama. The BDS-D supports materiel development, combat development, training development, and operational testing by providing a low-cost, effective alternative to proof-of- principle demonstrations, field tests, and operational evaluations in all phases of force development. The program approach will achieve seamless simulation of systems, including simulations for command and control, simulators for weapon systems/platforms, actual operational systems, and semi-automated forces. An open system design architecture, with a common set of protocols and standards to achieve interoperability of simulators, is the keystone of the BDS-D program development.
Use of the object-oriented design approach for networking crewed simulators and SAFOR provides a multidimensional simulation of the battlefield environment that allows insertion of the warfighter into the loop at all phases of force development and training. The simulated war- fighting environment can be packaged or scaled to address a variety of uses, so that smaller segments of simulation can be included in larger synchronized environments when required. This will be achieved through a system of local area networks (LANs) of low-cost battlefield simulators, experimental and high-fidelity remote nodes, and SAFOR, all linked together via a system of long-haul networks. This system will provide a virtual combined arms and joint combat operations environment for materiel and combat development and for operational testing exercises.
Through the use of current and emerging long-haul data communication capabilities to create wide-area networks, simulation capabilities will be resident at geographically separate sites and linked together to form much larger synchronized simulation environments. This characteristic allows the simulation environment to be "packaged" in sizes and places corresponding to the size and location of actual units for evaluating weapon system, force development, and training concepts (see Figures VI-21 and VI-22).
Figure VI-21. With BDS-D, wargame exercise referees can observe training operations from any vantage point on the battlefield while remaining completely transparent to the players.
Figure VI-22. BDS-D will give weapon system operators the ability to more realistically train with non-line-of-sight missile technologies.
Armored Systems Modernization (ASM) is similarly being analyzed under the BDS-D concept. ASM mobility, weapon station stability, and ride quality, as well as the survivability of all the ASM variants, will be evaluated in a true combined arms simulation. Anticipated ASM capabilities like the Vehicle Integrated Defense System (VIDS) and Combat Vehicle Command and Control (CVCC) are being simulated and evaluated via the BDS-D test bed resources; crew controls and displays for the Line-of-Sight-Anti-Tank (LOSAT) variant of the ASM family have been "prototyped" within the BDS-D resources and successfully used to describe valuable human factors modifications to be pursued by the weapon system program office.
The Joint Precision Strike Demonstration (JPSD) is using DIS and wideband networking as a central experimentation and analysis element of the Precision/Rapid Counter Multiple Rocket Launcher (MRL) ACTD. The objective of JPSD is to demonstrate an Army all-weather, day/night sensor-to-shooter capability to locate, identify, and eliminate high-value, short-dwell targets and assess damage within tactically meaningful timelines. The specific objectives of the ACTD are to demonstrate the use of current and emerging technologies to rapidly defeat a MRL attack against South Korea and to provide leave-behinds that enhance the CINC's warfighting capabilities. Through use of DIS, JPSD has developed a distributed network, controlled by the JPSD IEC (see Figure VI-23), that combines live and simulated events into a real-time, virtual representation of the warfighting scenario. JPSD has used this capability to integrate a live ATACMS missile firing, live sensors (UAV and an advanced sensor), software simulations of precision munitions and targets, and manned intelligence and fire support C2 nodes to demonstrate the end-to-end timeline for acquiring, targeting, attacking, and assessing damage to a variety of target classes. FY95-96 efforts concentrated on in-depth experimentation for the MRL scenarios and on providing leave-behind capabilities.
Figure VI-23. Full Up DIS Simulation
Click here to view enlarged version of image
The BDS-D will continue to expand, using additional modeling assets that either exist already or are under development. The goal by the year 2004 is to achieve seamless linkage of battle simulations, live field simulations of tactical engagements, and networked simulators using the object-oriented network design approach.
f. Test and Evaluation Simulation
Technological progress must be complemented by test and instrumentation facilities, including test and evaluation simulation, that can measure the technological progress being achieved. Environmental and safety concerns increasingly impose constraints on test and evaluation facilities. Maximizing simulation will minimize these environmental and safety issues. The full-scale testing of new weapon systems is both costly and time consuming. The ability to simulate the physical conditions of the battlefield for test and evaluation reduces the time to obtain data and cost. Bringing the test environment under laboratory control provides high quality, reproducible data that can be recorded and analyzed during the test process.
The Battlefield Distributed Simulation-Developmental (BDS-D) program (see Section d, above) will ultimately be used to support test and evaluation.