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The Tactical Systems Simulation facility at Lockheed Martin Aeronautics Company in Fort Worth lets warfighters climb into the cockpit of the Joint Strike Fighter and fly against a realistic threat environment of 2010, before the actual fighter leaves the runway, before it rolls off the production line, even before it leaves the current concept development phase. Along with a realistic threat environment, warfighters can also expect to find realistic aircraft systems and a state-of-the-art facility that combines the two. By the time the JSF program enters the engineering manufacturing development phase, warfighters will already have flown over 750 virtual combat sorties. This representation of the JSF is immersing warfighters of today in a virtual battlespace of tomorrow.

Making the virtual battlespace real means having authentic controls and displays interact with aerodynamic models to reflect JSF-like performance; means projecting accurate JSF-like signatures and operating avionics modeled on planned real JSF hardware; means flying in a battlespace with realistic potential threats and real-world topographies presented in a 360-degree physical environment in high resolution format. In simple terms, this simulation equates as much as possible to reality—minus g forces.

The cockpit for this virtual battlespace illustrates the latest technology controls and displays that will be incorporated in the production versions of the JSF. Right now, two full-up JSF cockpits, each with displays and controls, can accurately mimic the latest iteration of the pilot-vehicle interfaces.

The cockpit controls and displays are prototyped in a separate cockpit development and demonstration station. This station allows numerous cockpit design options, such as touch screens and voice-activated commands, to be prototyped and evaluated in a cost-effective, unclassified environment. The design is then transferred into the TSS for evaluation in a more stressing tactical environment. Design improvements are then recommended for re-implementation in the design and development station.

The aerodynamic performance models, which determine the relationship between pilot inputs on the flight controls in the simulator and simulated aircraft maneuvers in the virtual battlespace, are based on the same models used in the handling quality simulators that support JSF flight test and maturation activities for the production designs of the JSF. These mathematical descriptions of the flight envelopes are continually updated with results from wind tunnel tests and account for all three JSF variants—conventional, carrier-capable, and short takeoff and vertical landing.

The signature representations of the JSF, or how identifiable the JSF is on the radar screen, are generated with prediction algorithms and data derived from physical testing of a full-scale signature model of the aircraft. "Low observable technologies, a key contributor to the effectiveness of any fifth-generation fighter, is a critical factor in assessing the JSF’s combat effectiveness against potential threats," explains Tammy McNeley, who leads the JSF virtual effectiveness analysis team.

JSF avionics provide another reality to the TSS because many of the avionics algorithms used in the TSS are physics-based models of sensors. For example, the models that describe the various functions of the radar account for atmospheric attenuation and propagation effects. "Northrop Grumman, the radar manufacturer, has provided a radar model that closely matches the expected performance of the real hardware," notes McNeley. "Air-to-air and air-to-ground functions track both stationary and moving simulated targets. With these functions, warfighters can search and acquire ground targets while continuing to monitor potential air threats."

These avionics models take into account certain real-world occurrences. "Even shadows cast by vertical objects, such as buildings, trees, or electrical poles, appear on the radar image displayed in the cockpit," adds McNeley. "These images are generated dynamically while the aircraft is flying, so the angle of the shadows reflects the orientation of the aircraft to the object as well. The resulting dynamic images are stunningly realistic."

From the PVI to the sensors, Lockheed Martin is focused on using the best representation of the key components of the JSF in the TSS. "By combining these high fidelity components, the warfighter is provided the best representation of aircraft systems that is currently available to assess the survivability and lethality of our JSF," continues McNeley. "And it is more than a paper description of the aircraft. It is a high fidelity approximation of the actual JSF that the warfighters can fly and experience." And to reduce cost while maintaining fidelity, Lockheed Martin is sharing software across the technical disciplines. "We are demonstrating in this phase a capability that will be the key to an affordable manufacturing development phase—software reuse."

The threat environment adds yet another dimension of realism to the TSS. The environment, called the Strike Warfare Collaborative Environment, is provided and validated by the US government. It accounts for all the combat entities—tanks, trucks, aircraft, missiles, and bombs—in the scenario. It also controls their locations, motions, behaviors, and interactions with other entities in the scenario. The environment consists of both threat and friendly representations of the integrated air defense systems and command and control nodes, surface-to-air missile systems, antiaircraft artillery, air interceptors, and support aircraft. "The mission-level model chosen by the government to anchor the threat environment provides representations of almost all threat elements—missiles, guns, and aircraft," notes McNeley. "If more fidelity of an element is needed than the mission level model can provide, say a detailed model of a missile seeker, the architecture can incorporate a higher fidelity model easily. This ability to adopt more accurate threat representations is a real attribute of this system."

The models serve the added benefit of being able to run in either realtime in a simulator or in batch mode for constructive analysis; the data results can then be fed back nd forth between the constructive and virtual analyses. "This ability to link constructive and warfighter-in-the-loop analyses greatly enhances our analytical capability," explains McNeley.

A further increase to simulation fidelity comes from the imagery database of the combat arena developed by the government. This database, referred to as the multispectral database, describes the size, shape, temperature, and reflectivity of the ground and the ground targets in enough detail for the sensor models to read and produce realistic images. And that means real-world clutter from trees, bushes, cars, trucks, houses, buildings, and so on. These images are then displayed to the warfighters in the JSF cockpits. This critical capability ensures that warfighters see consistent pictures of threats in the battlespace.

McNeley explains, "If a tank is parked at a road intersection and the warfighter is close enough to see it, then he will see it when he visually looks out the cockpit. If he takes a radar image of the road intersection, he will see the same tank sitting at that intersection. If he looks at the road intersection through the electro-optical targeting system, he will also see the same tank at that same road intersection. Everything matches because the information is derived from a common database."

Add the human element to the threat characteistics and densities expected in the 2010 timeframe and the TSS portrays the combat effectiveness of the JSF. "The TSS is first and foremost a manned combat effectiveness simulation," explains Gene Dawson, team lead for the JSF TSS, "with all the basic simulation software for the aircraft and the combat environment."

Unlike cockpit simulators of the past that were enclosed in spherical structures, the two cockpits comprising the TSS reside in polyhedron structures called wide angle single eye point domes. Each structure joins eight flat panels, made of Lexan, at odd angles to form a 360-degree field of view for the pilot. The visual environment is projected through the rear of the translucent panels. These new domes increase the brightness and the contrast of the projection ten-fold and the resolution six-fold. To the pilot of this virtual cockpit, the TSS projects a very realistic visual scene complete with overlaid satellite imagery, weather, sun angle shading, and ground clutter.

"Achieving visual projection better than the human eye (eye-limited resolution) for the entire 360-degree envelope of vision is the ultimate goal for any high-end air-to-air combat simulator," continues Dawson. Though the computers rendering the imagery are fifth generation, achieving real world visual detection is still beyond state-of-the-art. To compensate, the TSS supplements the display capability with eye-limited resolution target projections in the front four panels of the polyhedron. These target projectors provide air and ground target displays at resolutions the warfighter needs to perform targeting tasks within-visual-range. During the next program phase, this air-to-air capability will be projected from the rear hemisphere as well.

The overall system is the first to combine state-of-the-art air-to-surface and air-to-air target projection into the same visual system. Explains Dawson, "We can do full mission simulations that involve both air-to-surface targeting and air-to-air targeting in the same mission, just like in the real world.

"Design engineering and constructive analysis can’t accurately predict the dynamic performance of a weapon system when seasoned warfighters fly as a flight of four," notes Dawson. "Providing four JSF cockpits allows several ground-breaking aspects to be introduced into simulated evaluations. The warfighters will then act in their native environment using intra-flight communication, crosschecks, and coordinating tactical advantages in a dynamic environment to meet the mission objective."

To manage these multi-ship simulations effectively, Lockheed Martin has coupled the TSS with a Virtual Battlefield Management Center. The technology that enables this combined virtual mission is called distributed interactive simulations. With this simulation, multiple players can be centrally controlled while participating in the same virtual environment. This distributed simulation architecture also expands the arena of play to include the command and control elements that control and feed information to the warfighters from off-board sources, such as JSTARs, AWACs, and forward air controller stations. This configuration will be used later to support JSF system interoperability assessments.

The TSS evolved from a program in the early 1990s that developed requirements, avionics, sensors, and a manned simulation for an advanced cockpit. "Having this core simulation capability available at the beginning of this phase of the program was a huge benefit," says Dawson. The simulator was later adopted as the beginning point for the JSF simulation.

Thanks in part to that early cockpit simulation program, the JSF TSS has advanced further earlier and at significantly less cost than any other tactical simulation program. "Our simulation software is the most complex ever developed at Fort Worth—on the order of two million lines of code—probably by a factor of four or more," Dawson continues. "In spite of this complexity, it is stable and dependable. We have never failed to complete a VIP demonstration successfully." Lost data runs are limited to a finger count, which takes on greater meaning in the face of continuous and aggressive software development, numerous computer hardware upgrades, visual system upgrades, cockpit upgrades, and two facility moves. The reliability of the software performance hits the ninety-nine percent range.

"By the time we enter the next JSF program phase," adds Dean Hayes, who leads the JSF weapon systems analysis team, "we will have put the JSF TSS through almost 800 simulated combat sorties, through eleven major virtual studies, and about thirty VIP demonstrations. The TSS will enhance flight testing in the next phase by reducing actual flight time required for a data point, by combining with actual flight testing to generate a more complex and realistic stimulus, and by producing combat environments and conditions that are simply too dangerous for flight test.

"We have done nearly everything we set out to do in 1996," continues Hayes. "Our last contract simulation in the TSS facility was performed to the day as scheduled two years earlier. Furthermore, the contract task was completed exactly on budget. The software and hardware design teams in the TSS have done an incredible job. We see the benefits of that every day."

Mary Lou Vocale is the editorial assistant for Code One .