Current Trends in Distributed Interactive Simulation (DIS)

• and Military Training Applications

• Copyright (C) 1995 David Alexander

• Appeared in the journal Military Simulation and Training

• This Article may be printed and distributed so long as the

• copyright notice above is not altered or removed.

Widespread procurement cutbacks and decreased funding for extant research and development, acquisition management reform, a downsizing trend in conventional force structures, a perceived decline in global threat levels and other factors, have all militated toward an increased emphasis on simulation in military training applications.¹

In the U.S., the Clinton Administration has opted to either delay or defer several modernization programs for the armed forces and instead exploit an extensive weapons stockpile dating from the Reagan era. But while making less do more is the current watchword in Washington and the Pentagon, in one specific area, that of information technology, present R&D investment has held steady, if not increased perceptibly.

• According to Defense Secretary William Perry, the present focus in U.S. military R&D is on the enhancement of current systems by the utilization of new generation infotechnology to increase their functionality by a projected "factor of ten." But any attempt to fine-tune battlefield systems to such exquisite performance levels cannot succeed without due attention paid to any combat system's most critical component: the soldier-in-the-loop. Training, therefore, is key, and electronic simulation technologies -- capable of providing highly realistic, full-scale, force-on-force maneuvers -- are pivotal to the goal of maintaining combat-ready forces in an era of military fat trimmed with the holy zeal of Inquisitional monks subjecting heretics to autos de fe.

However, due to budgetary constraints which drive contemporary R&D efforts, no single service branch can currently marshall the resources to develop stand-alone simulation systems even remotely capable of meeting mission demands. Additionally, the U.S. Congress has mandated that interservice exercises become the training modus vivendi, encouraging, if not requiring, architectures and standardized protocols shared in common between the armed service branches.²

• Distributed Interactive Simulation (DIS) represents a training methodology which has the potential to arbitrate the sometimes oppositional realities of post-Cold War geopolitical and economic limitations and provide a scaled-down military force with qualitative gains over quantitative losses. It is a means, according to the conventional wisdom prevailing in today's political and military spheres, of doing things smarter and cheaper. This observer will also add that the identical training philosophy well served the numerically inferior army of the Roman Empire throughout much of its history.

• The operant principle underlying DIS is to enable combat personnel dispersed or noncolocated geographically to engage in simulated combat exercises in realistic battlefield environments. All participants in DIS Joint Training Exercises / Combined Training Exercises (JTXs/CTXs) appear to share the same virtual battlespace. All participants have the ability to perform wartime tasks across a continuum of anticipated threat scenarios including interaction with OPFOR personnel. DIS technology provides commanders with high mobility on the simulated battlefield, enabling real-time viewing of both simulation ground truths and the overall developing picture. DIS technology provides enhanced support for feedback, evaluation and assessment procedures integral to the training process.

Under the aegis of DOD/ARPA, the military service branches in the United States have been utilizing distributed simulation training environments for some years. In this respect, there is nothing new about DIS. What is new, however, is the doctrinal emphasis now placed on modularity, standardization and interservice commonality. What is also new are the technological advances that are driving the adoption of DIS standards and the increasingly swift pace of maturing systems that can be exploited in today's mission-critical training applications. In an era of defense policy where jointness is a central tenet, if not an article of faith, DIS promises to extend the operational mandate to training applications as well.

• The Advanced Research Project Agency (ARPA) has identified a number of key benefits to be derived from DIS training applications over more conventional systems. These are:

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  • DIS enables real-time linkages of combat platforms and individual combatants in the virtual battlespace. Non-sensory data such as EW and TEMPEST effects can be made part of the training scenario. Mistakes altering the ground truth of the simulation can be programmed into the application to duplicate the "fog of war."

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  • DIS provides support for a multifaceted training environment based on an open systems architecture which is modular, transportable and transitionable. Training applications can therefore be quickly tailored toward changing operational needs and the differing requirements of the individual service branches.

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  • Shared network standards and protocols maximize investments in systems already in existence; governmentally mandated cost-cutting measures would be served. Off-the-shelf technologies and components increase modularity and affordability, resulting in "plug and play" interchangeability.

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  • Extant and emerging simulation and training systems would both be accommodated by DIS compliance. Interservice training operations would benefit from unification of standards and protocols, resulting in the capability to convey a wide range of threats, including terrorist activities, and operations other than war (OOTW).

• One sector of DIS application cited as having unique importance impacts on the dismounted infantry soldier. These formations in general, and special operations forces in particular, have not had the benefits of high-technology simulations training that has been available to other branches of the armed services for some time. The use of distributed simulation technologies would permit SOF units, such as U.S. Army Rangers, to conduct exercises in virtual battlespace, enabling interactions heretofore only possible in complicated and expensive real-world training missions.

• The U.S. Army's Simulation, Training and Instrumentation Command (STRICOM) is making efforts in this sector with the Virtual Environment Training Technology (VETT) program. VETT, an individually immersive virtual reality (VR) technology, offers protocols tailored to the specific training requirements of infantry troops. This "Little VR" is different from the "Big VR" of vehicle- or platform-centered electronic battlefield simulations because it enables combatants to directly interact with the battlespace, i.e., without doing so through the medium of joysticks, control panels, display consoles and the like.

Systems currently in use with VETT simulations include head-mounted displays (HMDs) and wired (tactile or force-feedback) gloves which provide an immersive VR environment for the user. Utilization of these devices, however, has prompted criticism from psychologists and behavioral experts -- including the Army's own -- that programs like VETT would will turn out "arcade cowboys" ill-suited to meeting the demands of real-world combat situations. DOD, however, contends that a training paradigm based upon new technological models can transcend the limitations imposed by current "off-the-shelf" simulation hardware. The use of advanced utostereoscopic, volumetric and holographic display environments -- such as those utilizing laser excitation of rare-earth pixels and spinning helixes to generate holograms -- have been proposed as possible alternatives to what is presently available.

• Dismounted infantry capability (NPSNET-DI) has become part of an enhancement package including walk-in synthetic environments (NPSNET-DI-WISE) at the Naval Postgraduate School Simulation Network (NPSNET). The original mandate of NPSNET was to develop simulator technology based on SIMNET and other DIS protocols, including the Distributed Interactive Simulation standard protocol devised by IEEE, enabling modularity and shared throughput among DOD simulators via the Defense Simulation Internet. However, the organization has since become a key player in ARPA's DIS development program which straddles the interservice gamut.

• The new NPSNET capabilities were demonstrated last spring at the 1994 Individual Combatant Modeling and Simulation Symposium which was held at the U.S. Army Infantry School at Fort Benning, Georgia, in conjunction with Sarcos Inc. and simulation labs from the Universities of Utah and Pennsylvania. The event marked the first public demonstration of the insertion of individual combatants into electronic battlespace that was fully DIS compliant.

• The enabling hardware for the soldier-machine interface in the NPSNET scheme is the Individual Port (I-Port), which is a wraparound instrumentation package including HMD and wired gloves. Three infantry soldiers in I-Ports demonstrated a number of combat activities in the virtual space of the simucises. These included dismounting from a Bradley fighting vehicle, aiming and firing an M16A1 combat rifle, issuing hand and arm signals from a variety of positions, and engaging in mobility exercises including walking, running and dropping to a prone position. Large display screens and audio enabled attenders to see and hear the ground truth experienced by the demonstrators.

• Another recent demonstration of DIS compliant training technology on the Defense Simulation Internet which took place at an American Defense Preparedness Association conference on simulation and training earlier this year, focused on the capabilities of a reconfigurable simulator developed jointly by Texas Instruments' Defense Systems and Electronics Group and ARPA.

• The simulator is capable of being multiply configurable to a range of existing combat platforms. These currently include the M2A2 MBT, HumVee MPV and the Light Contingency Vehicle (LCV) among other concept vehicles. High-fidelity simulation capabilities, based on real-time engineering models reconfigurable to combat environment specifications and running on a Silicon Graphics Onyx Reality Engine written in C and C++, include fire control emulation, sensor-based threat assessments and provide capability for after-action crew performance rating and analysis.

• Also harnessing the power of a Silicon Graphics computer in tandem with off-the-shelf components and commercial software to provide a low-cost aircraft training simulator, is the COTS system developed by Lockheed and demonstrated at the 1994 International Aerospace Exhibition in Berlin, Federal Republic of Germany. The COTS system is optimized for F-16 training applications, and is DIS-compliant. A new trainer, the Crew Station Mission Equipment Trainer (CSMET) being developed for the OH-58D Kiowa Warrior (KW) helicopter by the U.S. Army will also reportedly be DIS-compliant.

• Although the primary funding focus on DIS in the U.S. military establishment has been on the technology per se -- one that is, by definition, a modular technology and therefore independent of fixed training locations -- some new centers for training of military personnel in DIS compliant environments have been established in FY94.

• One of these is the Joint Warfighting Center (JWFC), located at Fort Monroe, Virginia. The JWFC will provide training in combined operations during Joint Training Exercises / Combined Training Exercises (JTXs/CTXs) among participating branches of the armed services. It will have the capability to conduct four major and eight minor simulation training exercises per year, which will incorporate three levels of simulation.

• Joint Theater Level Simulation (JTLS) exercises are those which facilitate operational-level wargaming maneuvers. Joint land-sea-air and SOF can be accommodated with participation by up to ten factions in a 2,000-square mile virtual battlespace.

• Joint Conflict Model (JCM) utilizes Defense Mapping Agency terrain database input to facilitate high-resolution simulation across a simulated space of some 360 square miles. Up to five factions are supported in this mode with simulation resolution realistic down to the level of individual weapons platforms and infantry troops.

• Aggregate Level Simulation Protocol (ALSP) facilitates force integration amongst Army, USN, Marine and USAF battlespace elements. With an estimated cost of some US$2 million per exercise, this level is the most complex and expensive of the three JWFC modes. Sophisticated EW and logistical simulations are supported at this high-end of performance.

• Located at Kirtland AFB, New Mexico, the Theater Air Command and Control Simulation Facility (TACCSF) is a USAF training and testbed facility with dynamic linkages to the National Test Facility in Colorado Springs, Colorado, ARPA's WARBREAKER synthetic battlespace environment, the Air Defense Initiative Simulation Technology facility based in Arlington, Virginia, the USN R&D facility in San Diego and the Pentagon's Theater Battle Arena. The air combat environments generated by TACCSF permit multiple simulations of up to six thousand simultaneous air and ground contacts in a battlespace up to 2,048 by 2,048 square miles at user-selectable global locations. Utilizing DIS-compliant protocols, TACCSF can support interactive linkages with a large number of individual and joint simulation exercises.

• Joint training exercises for space warfighters, via leveraging of the TENCAP (Total Exploitation of National Capability) program are also part of planned objectives at the USAF Space Warfare Center.

• By far the most ambitious and far-reaching DIS-compliant program currently underway, however, is the U.S. Army's Warfighters' Simulation (WARSIM) 2000 project, over which STRICOM presides. WARSIM 2000 aims at providing a comprehensive training environment utilizing combat scenarios taken from across the operational spectrum.

• The system is intended to provide extensive support for training combat personnel from the battalion level up to the theater level and will support joint U.S. and global coalition force training applications. WARSIM 2000's operational architecture will make use of fixed regional facilities to run major simulation models. However, for portability of applications, Simulation Support Modules (SSMs) are to provide support functions at local training bases under the direction of a senior controller. SSMs are to be fully portable and stand-alone.

• Full DIS compliance with present and emerging protocols is a central facet of the system's design philosophy. Selective uploading/downloading of simulation information from distributed, DIS-compliant databases, and the interactive exchange of this information to produce immediate changes in the simulated training event or events is to be supported, so that training users can rapidly build or modify scenarios. Linkages will be supported to future DIS-compliant models of other services, including USN Enhanced Naval Wargaming System (ENWGS) and USAF Air Warfare Simulation (AWSIM).

• The operating system for the network's computers is to utilize POSIX-compliant open systems architecture. Organizational command and control systems and supporting communications protocols such as Army Tactical Command and Control System (ATCCS), Standard Theater Army Command and Control System (STACCS) and Army WWMCCS Information System (AWIS) are to be supported. ATCCS Common Hardware compatible personal computers utilized by training supervisors and auditors must also function in the network. Software architectures supporting distributed computing must be modular in design, facilitating rapid modifications that do not compromise the overall system.

A distributed network of simulation centers under Army control is planned for the ramp-up phase of system development, each with all necessary computer hardware, software and communications equipment to run simulations. Exercises up to the corps-level would be supported at each simulation center of the WARSIM network. Networking the centers as DIS compliant nodes would provide support for multi-corps-level exercises. Each WARSIM node will be staffed by combined military and contractor personnel to provide support for exercise planning and execution, opposing/surrounding forces simulations, after action review and simulation control.

• Three simulation levels or mission profiles will be supported by WARSIM 2000. These are:

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  • Multi-echelon Command Post Exercises. These support training simulation operations from corps level down through brigade headquarters. Training occurs simultaneously in an integrated scenario. Duration for multi-echelon CPXs is from four to nine days. Depending on participating units (i.e., corps or division), operations are continuous for 96-198 hours. This is the highest-level operating mode.

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  • Single-echelon Command Post Exercises. Simulation exercises for battalions and brigades, and within service schools, are supported at this level. Commander and battle staff of the unit undergoing training audit the simulation from either actual CPs in the field or from mock-ups. Higher and subordinate and adjacent unit personnel participation is supported. Operations are conducted over a period of three to four days. Operations are continuous for 60-78 hours. Up to six simultaneously occurring and independent single-echelon CPXs will be supported.

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  • Seminar mode. The least strenuous operational level supports exercises of active and reserve units and institutions. Operations take place during a one to three day period and are continuous for a period of 20 to 25 hours. Up to six simultaneously occurring and independent training seminars will be supported.

• The types of physical environments to be supported during training events by WARSIM 2000 is wide ranging. Simulations are to duplicate environments ranging from jungle, arctic and desert. Operational conditions to be supported are to include the initial and residual stages of NBC and CBW deployment, and include support for mobile, projected, fixed-smoke effect and flame weapons, as well as reduced visibility conditions and night.

• Subwarfare and special operations forces operations are to specifically be accommodated by the system. Training events are to support small unit infiltration, reconnaissance and search, locate and annihilate (SLAM) missions against targets military and civilian, including supply points, bridges, dams, weapons dumps and power generation stations. The simulated training events will enable SOF to utilize exotic equipment such as laser target designators to enhance delivery of PGMs and duplicate elite unit movement through battlespace that is stealthier than that of conventional infantry. EW, PsyOps, deception, terrorist acts and the taking of enemy prisoners of war (EPW) are also to be accommodated.

• The capabilities of fixed and rotary wing special operations aircraft to perform infiltration and extraction operations from denied areas, including NOE and SAR, are to be duplicated in WARSIM 2000 training events. Space, air, naval and amphibious operations must also be represented as they impact on Army operations in a realistic manner during simulation exercises.

• After-action reviews (AARs) will be supported via an AAR and Evaluation System (AARES). AARES will utilize several formats optimized to record training events specified by users and respond to statistical queries, even during the course of simulated exercises. Real-time false three dimensional screen displays, overhead viewgraphs superimposed on maps and showing the location of units in conjunction with symbol graphics and text messages are some of these formats. Mission commanders and training supervisors will have the capability of executing database search operations of individual or multiple training events in order to generate standardized briefing reports. AARES is also to include support for the Tactical Decision Support System (TDSS).

• While there is a clear mission for DIS-compliant training applications and technologies, especially in the area of infantry and special forces operations and large-scale combined arms battles against multiple or composite threat forces, critics have cited a number of drawbacks to full implementation of advanced distributed interactive simulation as a viable training modality.

• The most common of these concern issues of affordability and technological feasibility. At the present time it is still generally less expensive to set up and conduct training simulations in the conventional way, and in some cases, to actually put troops on the ground. Simulator sickness is another common problem connected with prolonged exposure to immersive environments, given the current state of the art. It is caused by the discrepancy between visual motion cues generated by the system and those provided by the human senses. In interactive, immersive networks these symptoms can be exacerbated by the added stresses to the human nervous system brought on by update lag-time, producing such reactions as headache, nausea and vertigo.

• Also, despite ongoing efforts at adopting open architectures, a lack of common standards and protocols between the services is still the rule rather than the exception. Contractors have cited special problems in systems-design geared to SOF requirements, due to mission complexity and other factors including, but not limited, to cost.

• Significant improvements in graphic fidelity, terrain representation, network throughput, protocol sharing and system security will need to be made, and funding issues will need to be resolved, before distributed synthetic battlespaces become commonplace training environments. But necessity has always been the mother of invention, and economic imperatives drive these resource-scarce times. In 1988, Operation Reforger staged corps-level combat exercises in Europe at a reported cost of some US$53.9 million, while a simulated version of Reforger staged in 1992 cost less than half and generated abundant after-action data that could be analyzed in depth. It may now make sense to reinvent the wheel.

¹ A report released last August by a DOD-appointed task force on U.S. military readiness characterized forces as "acceptable in most measurable areas" but warned of "pockets of unreadiness" that might result in a "hollow" force reminiscent of the late 1970s and early 1980s. The report also emphasized modeling and simulation as key technologies in support of higher readiness.

² As an example, modifications had to be made to training systems in use by the USAF before that service branch could participate in interservice exercises held last summer at the National Training Center in California. Had these modifications not been made, decreases in funding for a variety of programs would have been the consequence.