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Centralized or distributed - a simulated discussion.

Centralized versus distributed--the conflict of philosophies appears with increasing frequency these days. Whether discussing economics (say, the centralized planning endemic to communism in contrast to the frequently more distributed activities of capitalism), EW self-protection or computer architectures, to name a few examples, the pros and cons of centralized and distributed approaches have become pertinent subjects for debate in a variety of disciplines.

Simulation-based EW training has become one of these disciplines. In the past, simulation resources have tended to be centralized, either at outdoor training ranges or indoor facilities equipped with devices like weapons systems trainers. But the cost of procuring and maintaining large simulation systems has become hard to justify in today's shrinking budget environment. The cost of recycling a similarly shrinking number of EW operatives to relearn a rapidly changing threat environment also seems increasingly prohibitive -- both in terms of money and maintaining force levels.

Thus, the idea of developing smaller systems and placing them closer to forces in the field has gained popularity, and concepts such as Distributed Interactive Simulation (DIS) -- whereby simulators in widespread locations could be networked, thus providing greater capabilities and easier access to users -are bandied about at forums and seminars. But will all this talk lead anywhere? A look at some of the programs now underway reveals that while distributed simulation may be on the horizon, getting there will be an evolutionary, not a revolutionary, process.


The gospel of distributed simulation has certainly been spread to the Air Force. Speaking at a symposium last year, Dr. Robert Barthelemy, director of the Training Systems Program Office at the Aeronautical Systems Center (Wright-Patterson AFB, OH), described a meeting of the service's simulation minds held earlier in the year. The Air Force looked at its current training systems -- "large..., pretty well immobile, certainly not distributed, not really interoperable," in Dr. Barthelemy's words -- and decided that something had to change. While some of these new directions echo initiatives in other EW areas -- taking advantage of commercial technologies and working toward interoperability with other services, for example -- others represent fundamental differences in the type of simulators the Air Force will seek and the kind of training these devices will provide.

Specifically, the service concluded that given the current budget and force structure realities, there would not be enough resources to train people as the Air Force had in the past; regardless, "we should at least train them to proficiency." Dr. Barthelemy said. In determining how to accomplish this task, the Air Force split its forces in two. "Mobility forces" (mainly transports) suffer particularly from a lack of aircraft for training purposes; thus. aircrews would receive proficiency training on simulators, leaving their first flights on actual airplanes only to those that were "revenue-generating" flights.

The second category, "combat forces," previously had used large, expensive simulators for training. As described by Dr. Barthelemy, "Not only were they terribly expensive, and we were forced to deal with geographical limitations and support limitations, but they were almost nonconcurrent the day that we fielded them."To overcome this problem, the Air Force has decided to move away from the large, centralized simulators to "distributed systems, unit training devices that were extremely inexpensive compared to the $100 million systems, put them in the field next to the forces that were going to use the actual weapons systems, and keep the training current," said Dr. Barthelemy. Such simulators, geographically dispersed, become prime candidates for a networked approach such as DIS.

However, Dr. Barthelemy acknowledged that it would take "some time" before the implications of this change in philosophy are felt by trainees -- as demonstrated by the potential cancellation of the On Board EW Simulator, which would have brought range-type EW training to the unit level (see "OBEWS May Land on Air Force Hit List" in the December 1993 edition of "EC Monitor," p. 30). Some simulation capabilities will undoubtedly remain centralized. One of these will reside at Randolph AFB, TX, where basic EW officer (EWO) training has been moved from Mather AFB. Here, the new AN/FSQ-T25 Simulator for Electronic Combat Training (SECT) to will provide the basics of EW to navigators with EWO ambitions.

According to program manager Maj Robin Hartsel, the SECT is a high-fidelity system that can provide three-hour simulated "missions" and one-hour labs to students learning fundamental EW skills. The instruction covers four areas: strategic/covert penetration, stand-off jamming/direct support, suppression of enemy air defenses and electronic intelligence collection/electronic support measures. To provide this wide range of missions, the simulator replicates the EW gear of such aircraft as the F-4G, RC-135, EF-111 and various fighter/bombers.

The basic system comprises six student stations and a two-seat instructor's console, from which the student stations may be monitored. (Expansion capabilities include a total of nine student stations and a second instructor station, according to Major Hartsel.) Each student station has four 19-in. touch screen CRTs. In use, the student has little control of the flight path of his or her simulated mission. However, the EW gear can be operated for the purpose of threat detection and countermeasures activation. Software resident in the system will record the student's efforts for later evaluation.

The SECT effort is in the engineering and manufacturing development phase, based on a contract awarded to AAI Corp. in 1992. Verification testing will take place this summer, said the major, with system delivery slated for April 1995. While the SECT hardly fits into the unit training philosophy espoused by Dr. Barthelemy, it will fulfill some interoperability ambitions by supporting joint training requirements with NATO, Canada, the Marine Corps and what Maj Hartsel described as "allied officers" who will attend staff-level training sessions. Meanwhile, just as centralized assets such as the SECT will not go away with the change in the Air Force's training philosophy, one can expect the training ranges will remain in place as well. The Air Force is increasing the capabilities of its air combat training ranges through a variety of programs. One of the more beneficial -- and one that may serve as a signpost toward increased use of interactive and interoperable simulation assets -- is the Joint Air Combat Training System (JACTS). According to Tom Cary and Buddy Hayes of the Range and Air Bases Systems Program Office within the Air For Materiel Command at Eglin AFB, the JACTS effort will greatly expand capabilities at the Nellis AFB Red Flag facilities, as well as the Navy's ranges at NAS Fallon, NV, and NAS Oceana, VA.

Using Nellis as an example, the JACTS program will increase the number of potential training participants from 36 to 100 and increase the current threat density from 50 to approximately 150, the Air Force representatives said. The keys to these improvements include a new tracking system and a computer-generated threat systems (CGTS) capability. The new tracking system will be based on the Global Positioning System and will replace the current ground-based methodology. The CGTS ability will supplement the range's current hardware simulators to provide modem "double-digit SA" threat simulation.

Like the OBEWS technology mentioned previously, the CGTS will electronically stimulate the aircraft's EW suite, based on its coordinates over the range. Unlike OBEWS, wherein the location of the simulated threats is loaded into the aircraft's computer via a cartridge prepared by a mission planning station, the CGTS will stimulate the EW gear via a communications link. The CGTS is superior to OBEWS in that it can handle air-to-air, air-to-ground and ground-to-air activities simultaneously and also allow interaction among several aircraft engaging the same threat scenario.

An RFP for the JACTS program should be issued this fiscal year, Cary and Hayes said; the actual date hinges on the results of a review of Air Force and Navy training requirements. The user community has requested delivery of the system to Nellis during FY 1997. The program will include the preliminary design and demonstration of a DIS interface -- illustrating OSD's commitment to interactive simulation.

In another example of range simulation work, service recently accepted from Sierra Research the second of a planned five sets of the Unmanned Threat Emitter (UMTE). The UMTE comprises a master control unit and up to five remote emitters which can simulate such ground-based threats as AAA and SAM batteries with approximately 90 dBW of transmitted power. The system is transportable, according to a source at Sierra Research, which may fit in nicely with the Air Force's desire for mobility.

Another range-based system now in delivery is the AN/MST-TI(V) Mini-MUTES. Like the UMTE, it operates in a master/slave configuration: its remote emitter units can replicate up to 10 RF threat signals. Deliveries began late last year and are expected to continue for at least another two years, according to a source at Harris Corp., where the systems are being built. The Mini-MUTES will be used to train bomber crews (and possibly fighter crews) in threat detection, countering and avoidance. The range of replicated threats includes blue and grey systems, based on a contract option awarded to Harris in 1992. The company has been working on the program since winning a production contract in 1990; Amherst Systems is a major subcontractor.

As a final example of Air Force EW simulator initiatives for training, the service has contracted with AEL Corp. (with CAL Corp. as a subcontractor) for the AN/FSQ-T22 ECM Aircraft EC Trainer System. Targeted for Cannon AFB, NM, it provides a flexible RF environment that can simulate up to 111 emitters simultaneously from a library of approximately 5,000. The FSQ-T22 equipment is housed in a 40ft dome; however, users can configure the system into a master/slave arrangement for remote operation.

The original contract called for the delivery of one system to the Air Force, with options for others. The initial system reached Cannon in the middle of last year, according to a source at AEL; it currently is undergoing an evaluation which could stretch into the second quarter of this year. Meanwhile, the Navy is watching the proceedings with interest; it has a funded option for up to two systems which could be triggered as soon as the system completes Air Force review. While initial reports had the Navy placing one system at Whidbey Island, WA, the ranges at China Lake, CA, and Fallon, NV, also are potential recipients.

Selected Avionics Aircraft

AN/ALQ-170 Antiship Missile Radar Simulator    A-6E, EP-3J, NKC-135
AN/ALE-43 Corridor/Burst Chaff Dispenser        EA-6B, A-6E, F/A-18,
                                               EP-3J, NKC-135, EC-24
AN/ALQ-167 Electronic Countermeasures Set      EA-6B, A-6E, F/A-18,
                                               EP-3J, NKC-135, EC-24
AN/AST-4 Radar Emission Simulating Set         EA-6B, EP-3J
AN/AST-64 Radar Emission Simulating Set        EA-6B, A-6E, F/A-18,
                                               EP-3J, NKC-135
AN/ALQ-99 Band 3 Airborne Jammer               EA-6B
AN/USQ-113(V)1 Communications Jammer           EP-3J, NKC-135, EC-24
AN/USQ-113(V)2 Communications Jammer           EA-6B
CMR-7220 HF Scanning Receiver                  EP-3J
MD-1203 Audio Modulator                        EP-3J, NKC-135, EC-24
AN/ALR-75 ESM Receiver                         NKC-135, EC-24
OE/320/A DF Receiver                           NKC-135, EC-24
AN/ALT-40 Jamming System                       NKC-135, EC-24
TREE Series High-Power Jamming Pods            NKC-135


Speaking of Navy simulation-based training, the service's philosophy includes both centralized facilities and distributed systems. Aircrew training assets tend to be centralized, with the

Naval Training Systems Center (NTSC) in Florida the hub of activity.

Many Navy pilots receive EW instruction on weapons systems trainers. For example, Advanced Systems Development Inc. is providing packages to emulate the ALR-67 and ALQ-126B for nine F-14A and -14B simulators based on an awarded granted by NTSC last year. Such weapons systems trainers undergo periodic upgrades as the platforms they replicate receive new equipment. Thus, as the competition to upgrade the P-3C comes to a head (see related story in this month's "EC Monitor"), a similar battle among contractors has ensued for a five-year contract to enhance the P-3 training simulator. Bids for the contract -- which carries a particularly lucrative supplies and services requirement -have already been submitted to NTSC. A source there said an award could be made this May. Of particular interest to makers of EW simulators is the requirement for stimulation of the ALR-66 ESM in the P-3 Team Tactics Trainer. Of course, if a platform doesn't receive new equipment, upgrades to its associated training devices aren't necessary. Thus, several EW simulator firms shared Grumman's disappointment when the Navy scuttled the EA-6B ADVCAP program. Current EA-6B trainers -- including two at Whidbey Island and another at MCAS Cherry Point, NC -- are concurrent with the ICAP II Block 86 version of the aircraft, according to sources at Reflectone, Inc. The company built one of the Whidbey Island trainers and upgraded the other two, based on contracts awarded in 1986 and 1987 (AAI Corp. served as a major subcontractor for the EW/tactics portions of the systems). The finn recently received an award to support and maintain the equipment

As far as surface ship training is concerned, the Navy prefers a more distributed approach in which the training assets are brought to the crews, as opposed to the other way around. Perhaps the best known EW training asset is the Fleet EW Support Group (FEWSG), which was melded with the Fleet Deception Group Atlantic in May 1992 to form the Fleet Tactical Readiness Group (FTRG). The FTRG possesses a fleet of airborne simulators that create a realistic threat environment against which SLQ-32 and other EW operators can hone their skills. The FTRG has undergone a significant amount of reorganization within the last year. Stewardship has moved from the recently disbanded NAVAIR PMA-253 to PMA-272. The three VAQ squadrons assigned the FTRG role also were disbanded last October, with the reserves now tapped to fill their shoes. However, the two NKC-135As and the EC-24A aircraft operated for FTRG by Chrysler Technologies Airborne Systems (CTAS) have remained relatively unaffected by these changes. CTAS both maintains the aircraft and provides the aircrews, according to a company source. As highlighted in the table, the aircraft have been tailored for the FTRG mission; the NKC-135s can carry TREE jammer pods on their wing pylons, as well as flying ALQ-167, USQ-113(V)l and ALT-40 jammers and AST-6 threat simulators. The aircraft was being fit checked for the ALQ-170 pods as this issue went to press.

The FTRG has proven a multipurpose 'capability, said the source. In addition to training US Navy crews, joint training exercises have brought benefits to allied and friendly nations in Europe and South America. While the nature of the training missions changes with the perceived changes in potential threats, the requirement for such an asset remains, said the source. Thus, while CTAS currently is in the last of five option years, the source expressed confidence that a follow-on contract will be fully funded. The fact that the FTRG also has proven useful in test and evaluation applications adds to its utility -- and to its future security as a viable program.

The Navy has other assets for shipboard training, however. The 20B4 and 20B5 Combat System Team Trainers from AAI Corp. provide pierside EW training for a variety of surface ships. Both systems hare undergoing major upgrades, according to sources at AAI. The 20B4, which provides training for DD-963-class destroyers as well as carriers and other surface ships, is being given an electronic face lift, including upgraded interfaces to all combat systems and the SLQ-32A systems (the present generation is compatible with the SLQ-32|V~2). There are four 20B4s in the Navy inventory, two on each coast. There are also four 20B5s. These also are being upgraded to the latest ship system configurations for FFG-7. including Block 0, 1 and 2 of the Close In Weapons System. Additional chaff launching compatibility (from two launchers to four) and soft-kill chaff modeling also are being added, while the EW library and ocean-modeling capabilities for the hull-mounted acoustic system are being expanded. Upgrading the SLQ-32 compatibility from the (V)2 to -32A version is being considered but is not under contract, the source said.


For its part, the Army has embraced mobile, interactive simulation as the technology of the future. It has taken a lead role in the development of SIMNET (the precursor of DIS), and its battle labs have explored DIS-related simulation technologies.

As for the technology of the present, many of the Army's simulation-based EW training assets are based at Ft. Rucker, AL, and the National Training Center. However. a new program now in production, called the Aircraft Survivability Equipment Trainer (ASET) 4, promises a mobile capability for training Army aircrews. Each ASET 4 team consists of six HMMWV-based vehicles designed to emulate a mechanized brigade-based air defense network. One vehicle acts as a command and control station, while the other five replicate RF and IR threats -- two for radar-directed guns, another pair for IR-guided SAMs and one for RF-guided SAMs. Six man-portable IR missile simulators can be employed as well. According to Bill Nicholson at the Army's Office of the Program Manager for Aircraft Survivability Equipment (St. Louis, MO), the simulators are not designed to be high-fidelity replications of specific threat systems; they are merely expected to be "real" enough to activate the helicopter' s EW gear. The production contract awarded last September to Siena Research calls for two to three systems; the Army hopes to buy as many as seven, Nicholson said. "More than one" of these will be stationed at the National Training Center, while others will be stationed around the country and perhaps overseas. According to sources at Sierra Research, the Air Force also holds options for ASET 4, which could greatly expand the production order.

Meanwhile, Nicholson reported that users are calling for "field-level" training capabilities, including systems embedded in fielded platforms. The Army has attempted to meet this demand through ASET 3, whereby platforms such as the RC-12, with its multifunction display and computing power, can carry at least some embedded training capabilities. ASET 3 capabilities are under consideration for the Kiowa and Apache Longbow helicopters, Nicholson revealed. MANY RIVERS TO CROSS

The question of centralized versus distributed simulation -- what kind of mix is appropriate, is distributed simulation even a viable proposition -- is but one issue facing planners as they draw the road map for future training assets. Other considerations, such as interoperability, commonality and fidelity (see "Fidelity Requirements for EC Training and Simulation" on p. 50), also demand attention as the services determine how they will meet their training requirements with dwindling monetary and human resources.

Yet an embrace of distributed simulation would fundamentally change both the way training is provided and the kind and quantity of systems procured. Thus both soldiers and salesmen will be paying close attention to the centralized versus distributed debate.


Competency in electronic combat requires more than the relatively straightforward ability to read computer-generated presentations of threat activity. It demands excellent cognitive and associative skills, which the specialist must apply in a time-critical, often high-stress environment. Training of these higher-level cognitive skills requires high-fidelity, highly interactive simulations.

This situation is not peculiar to EC training alone. It applies to all sensor-intensive combat domains, such as surface naval warfare and the training of submarine attack teams. The complexity of high-fidelity simulations for these combat domains stems from the need to (1) replicate the relevant portions of the physical environment, whether RF, acoustic, etc.; (2) choreograph both friendly and hostile sensor evolutions; (3) model and automate the sensor environment's complex responses to inputs made by personnel in training; and (4) maintain sufficient control of the training exercise to assure the delivery of a valid training experience with sufficient data collected to provide timely and effective post-training debriefs. The Components of Training

All training simulators address, to a greater or lesser degree, the three components common to all training tasks: procedures, psychomotor/skill acquisition and decision/cognitive. As applied to EC training, these components break out into the following training requirements:

* Procedures: equipment "knobology," sequence of control operation, knowledge of when to do what

* Psychomotor/Skill: rapid and accurate equipment operation, signal separation, display optimization

* Decision/Cognitive: visual and auditory display interpretation, particularly under ambiguous or noisy conditions with high signal densities; emitter recognition/identification; determination of emitter activity, intentions, level of threat; prioritization for working (countering, data collecting or dissemination, destruction); evaluation of the instantaneous EC environment for impact on tasking (situational awareness); anticipation of the future course of the engagement and possibly related engagements; decision on how and when to engage.

Cognitive process training drives the EC simulation requirement. If the specialist in training is to learn to make the correct interpretations about the electronic environment and to act accordingly, he or she must be presented with a simulated environment in which great attention has been paid to simulation fidelity.

Aspects of EC Simulation Fidelity

In the context of EC training, simulation fidelity has three aspects: signal fidelity, equipment fidelity and environment fidelity. These are discussed below.

Signal Fidelity: Faithful signal simulation in terms of parameter fidelity is an absolute requirement if students are to learn to recognize signals by aural and visual analysis. It is also an absolute requirement if the simulator must stimulate operational receiver processors. Relationships among all parameters and all signals must be correct, particularly as an emitter transitions from mode to mode. These simulations, while often difficult to accurately simulate, are important for the cues they offer the EW specialist.

The supporting software must provide convenient access to the details of signal parameters so that (1) multiple examples of the same emitter types (not event copies) can be presented; (2) complex pulse trains (various jitters and staggers, frequency modulation on pulse, coded data pulses followed by CW blasts, etc.) can be tailored; and (3) so that signatures can be kept concurrent with the latest signal intercept data.

Equipment Simulation Fidelity: Simulation of control operations and display formats is not enough. EC specialists must learn to recognize and cope with the aberrant behaviors and deficiencies of their equipment and the signal environment. Some of the effects of interest here are ambiguities and anomalies arising out of receiver processor software; noise that rides on received signals; improper antenna selection; and changes in observed pulse shape and width as a function of receiver saturation, bandwidth changes or off-tuning. Of course, the specialist cannot be exposed to these effects unless excellent correlation is maintained across both simulated inputs and audio and video presentations on all simulated equipment, such as receivers, DF and omni antenna systems, analysis displays, pulse and spectrum analyzers, etc. Environment Simulation: A comprehensive simulation of the EC environment is needed to train higher-level EC tasks. These include decision making, maintenance of situational awareness, ability to anticipate, task prioritization and resource allocation under the stress of combat. To close the training loop, however, the specialist in training must also see the results of his activities. The integrated EC environment must respond to the combination of changes in applied countermeasures, changes in the trainee's platform position or activity and changes in the position or activity of other simulated entities, such as friendly strike packages.

Thus is mandated the requirement for tactics models for each sensor system in the environment. These tactics models emulate the performance of both the sensor and its human crew. If they are not included in the simulation, the training experience becomes a series of disconnected episodes from which the dynamic nature of real-world EC is missing.


Some subsidiary EC training requirements can be met with relatively low-fidelity part-task trainers. However, the integration of the EC specialist with his/her systems cannot be truly trained or verified without a comprehensive, accurate, correlated, rapidly responding, high-fidelity simulation of the electronic environment, EC equipment and the tactics of the simulated entities. Samuel F. Bass, principal development engineer, AAI Corp.
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Title Annotation:includes related article
Author:Hardy, Stephen M.
Publication:Journal of Electronic Defense
Date:Feb 1, 1994
Previous Article:Military computing in the year 2001 and beyond.
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