planning, training, force development, organizational analysis, and resource assessments within the services. Examples of multipurpose constructive simulations include JANUS (Army), naval simulation system (NSS) (Navy), advanced air-to-air system performance evaluation model (Air Force), and joint warfare system (JWARS) (Joint Services). These and other selected models and simulations are briefly described and categorized in the addendum to this chapter.
The linking of constructive and virtual reality simulations into federated networks is the newest and most rapidly expanding application of simulations in the DoD arena. Advances in this area were born of the necessity to reduce costs associated with the development of training and weapon systems. All of the services are seeking means of maintaining the fighting readiness of units and large combat organizations that cannot be deployed or exercised in peacetime to the degree required because of environmental and cost constraints. In addition, in the joint and combined arena, the military services and joint service commanders have a range of requirements that involve the development of command and control doctrine, force readiness, and procedures for joint service task forces and combined international coalition forces that may best be accomplished with the support of simulation.
As noted above, training is a central concern for the military services. Key objectives of the Army's use of simulations in this arena have been to decrease training time, decrease the cost of training, and increase the realism of training events. The Army uses constructive simulations such as JANUS and Corps Battle Simulation (CBS) to train leaders and other decision makers. In the last decade, with assistance from the Defense Advanced Research Projects Agency (DARPA), the Army has developed virtual system simulators for use in local and distributed computer networks. For example, systems such as simulation network (SIMNET) and its successor, CCTT, were designed to provide training in crew maneuver and fighting skills, as well as to provide unit-level training up to the battalion task force level for organizations equipped with M1 tanks, M2 Bradleys, and AH64 Apache helicopters. Recent training applications have been focused on attempts to integrate constructive simulations with virtual and live simulations.
The Navy has developed an array of simulations to support team/crew, classroom, and shipboard training requirements. Simulation and simulator training requirements are focused on ship systems and fleet operations. Simulations of Navy command and control task force and fleet operations have been developed within all of the unified commands, including European, Atlantic, and Pacific.