At one time military electronics equipment established the benchmarks for capacity and speed. But commercial information technology now sets the pace, propelled by investment in consumer products. After a period of looking on enviously, the military has increasingly adopted commercial off-the-shelf (COTS) products, for both performance and cost benefits.
Certain factors constrain even greater COTS usage, however. These include the lack of hardening and the high rate at which commercially available products become obsolete. One sector in which COTS usage is immune to or is overcoming these drawbacks is simulation–particularly the processing-intensive visual systems. COTS components have become more acceptable to the simulation community.
Most simulators operate in benign environments and require little ruggedization. And strategies are evolving to mitigate the obsolescence issue. Visual systems for top-end machines, such as advanced mission and Level D flight simulators, may still have substantial customized content. But COTS elements, already well established at the flight training device (FTD) level, are appearing at the top level, too.
The constant requirement for greater visual realism drives the need for higher processing power and speed. Visual simulation leaders like Evans & Sutherland, CAE, Primary Image and Quantum 3D, for example, all rely on COTS to achieve cost/performance combinations acceptable to military and civil users alike.
Rendered by Fabriano
Primary Image first introduced a PC-based image generator (IG) some two decades years ago. More recently, faced with customer requirements for an affordable high-end, PC-based IG able to meet Federal Aviation Administration (FAA) and European Joint Aviation Authority (JAA) requirements, it developed its Fabriano product, named after the 15th century Italian painter, Gentile da Fabriano.
"We had to try to produce a top-quality product that will meet market expectations for price," says Alan Davenport, Primary Image’s president. "While commercial equipment was essential for that, we had to address the issue of COTS suppliers’ changing product lines or disappearing at a rate unacceptable to the vision community."
"We therefore developed an architecture that would make extensive use of COTS to exploit the high resolution and high polygon and pixel fill rates available to the PC market but without many of the constraints," he adds. "The ‘future proof’ architecture is an Ethernet local area network-based solution that is open and scalable, allowing for upgrades and selective replacement of components as they become obsolete."
"Combining COTS with custom-designed elements, [Fabriano] accepts the latest PC graphic chip sets and processors to provide multiple-channel imagery at high frame rates," Davenport says. "High processing power enables realism to be augmented with an improved weather repertoire, including rain and fog, along with battle effects like smoke, fire and flames. Synchronization between channels is catered for by a proprietary Hyperlock system."
Fabriano offers full-screen anti-aliasing, with no penalty to performance, says Davenport. (Anti-aliasing stabilizes images of line features, such as power lines and the edges of straight objects, which might otherwise appear jagged due to the way simulator imagery is generated from basic polygonal or triangular shapes.)
Davenport adds that Primary Image also has addressed the issue of technology lag, or the time it takes for innovations to make their way into simulation products. "Army officers have sometimes asked me why the graphics on a $1-million simulator are not noticeably better than those on their PlayStations at home," he says. "The reason is, suppliers to the military cannot accept the short product life cycles that game board designers do and must use chips that have demonstrated some maturity. Therefore, there is a delay in applying the latest, high-performance chips."
Fabriano’s architecture was designed to accommodate those chips earlier than would otherwise be possible, to achieve a development environment in which chip efficacy and reliability can be established. Fabriano’s realistic terrain effects reportedly have met the demanding requirements of helicopter crew training. Military helicopters represent a major simulation challenge because they often fly nap of the earth, where detailed visual cues are important. Through Tempest software, Fabriano can even show rotor downwash and marine effects from a hovering helicopter.
Primary Image recently won contracts from ProActive Technologies and L-3 Communications to upgrade the visuals on U.S. Army cockpit weapons and emergency procedures trainers (CWEPTs) for the AH-64 Apache helicopter. Under another contract, five fully synchronized visual channels are being provided for each of two helicopter simulators in Taiwan.
At the Defence Helicopter Flying School (DHFS) in Shawbury, England, the Royal Air Force relies on a Harmony image generation system from Evans & Sutherland (E&S) for helicopter pilot training. Troubles afflicting the original Harmony visual system product line reportedly were resolved in the Harmony 2 IG generation, in which E&S combined Intel Pentium processor technology with simulation-specific rendering hardware and an enhanced software system. An open, platform-independent architecture combines the disparate elements. Recent successors, the EXP line for military simulation and EP1000 CT for commercial applications, maintain this philosophy.
"Our latest EPX 5000 and EP1000 image generators incorporate standard processors for the geometry portion of the graphics pipeline," says David Figgins, vice president, business development, for the E&S Simulation Group. However, we still design our own special-purpose hardware for the rendering part of the architecture, which processes the pixels that are actually displayed on screen. As general-purpose hardware becomes more powerful, we expect to see it take over more of the total graphics pipeline."
"As we have used more and more commercially available hardware, our company has transitioned from hardware to software centrism," Figgins adds. "We used to spend a lot of our time customizing ASICs [application-specific integrated circuits] but, using hardware off the shelf, we can now concentrate more on intelligent software."
"The upper-end EPX 5000 product is complemented by the EPX 500, which relies more on PC image generation technology, and the EPX 50, which can run on any standard PC having a graphics accelerator," he adds. "COTS technology can provide polygon capacity several times what was available a decade and a half ago. Texture, in its infancy then, is now applied to everything.
"PC-based military systems can support realistic simulation of sensors, with features such as material attributes allocated on a per-texel basis–something not possible with polygons–adding to the realism of infrared device simulation in particular." ("Texel" stands for "texture memory element," a common measurement unit.)
Through a joint venture with Russian simulator and helicopter interests, E&S is to supply a SimFusion, PC-based image generator for a Mil Mi-8 helicopter simulator to be operated by Saint Petersburg Aviation Repair (SPARC).
E&S’ civil visual simulation product, EP1000, was launched late last year. Marketing communications coordinator, Joan Mitchell, says more than 20 systems have been sold. One contract is with CHC Helikopters in Scandinavia. Using COTS technology has enabled E&S to engineer a high-fidelity visual training tool for today’s FAA Level D flight simulators. A continuous texture feature augments scene reality with high-resolution, textured backdrops. Effects include detailed terrain and airport content; weather features such as variable-density layered clouds, fog, storm cells, and blowing and falling snow; and calibrated reduced visibility.
E&S, which also uses COTS in air traffic control simulations, believes that its recent transition to lower-cost COTS-based IG designs shared across its military and civil production lines will help improve profitability.
CAE and Quantum 3D
Rival CAE has used COTS in its simulators for two decades. It cites price, performance and development time advantages in its decision to base products such as its Tropos visual system on PC technology. CAE addresses obsolescence issues both at the design stage and in its product support philosophy. It replaces hard disks in host computers with higher-capacity models. And the company upgrades older memory and processor modules with recent, higher-performance types and updates original software with the latest issues.
Another leading player to have combined advanced COTS components with proprietary hardware and software for simulators up to full mission and Level D standards is Quantum 3D. "Our business model allows us to benefit from the R&D of companies like Intel, Microsoft and others," says a company spokesman. "This enables us to drive down development time and cost. Further, we are not burdened with vertical integration costs, such as for chip design, chassis design, manufacture and so on. We can buy the best a competitive market has to offer and deliver solid industry-standard, PC-based solutions with our own unique added-value features."
Quantum 3D’s high-level Independence visual simulation series relies on commercial-standard NVIDIA Corp. 3D graphic accelerator chip sets and a radical, system-level parallel architecture for the rendering element. Computing power for the rendering system is configured as a number of Intel processor-based "sub-renderers" arranged in parallel. These feed into a channel compositor that delivers fused, synchronized digital output.
A high level of parallel processing ensures rapid visual response without the high latency of other compositor schemes that can manifest itself as "simulator sickness," the spokesman explains. Quantum 3D claims that Independence’s latency of 37 milliseconds for 60-Hz operations is among the lowest for an IG.
The system has the power to supply advanced weather and maritime features, and geospecific details of selected target areas. For military simulation, precision sensor channels in Independence can replicate infrared, electro-optic and night vision goggle scenes. These channels take the compositor output and apply PC-based post processing to deliver sensor effects.
Independence runs with Quantum 3D’s Mantis open platform scene management software. Both this and the IG management system support an architecture that effectively decouples chips from their implementation, so that improved chips can be integrated rapidly at upgrade time. This is part of the firm’s intrinsic preplanned product improvement strategy for technology insertion. The company relies extensively on COTS components to secure this strategy and to achieve the goal of "four nines" (0.9999) effective system availability.
Quantum 3D’s image generators also are used with Adacel’s Max and MaxSim air traffic control simulator lines. The IGs operate with other off-the-shelf hardware, including Dell PCs and JVC projectors. MaxSim lets trainees view the results of their actions from several perspectives, including from above the airport and from the aircraft cockpit.
Visual Simulation Systems, associated with the Simulation Systems Division (SSD) of FlightSafety International, has adopted an open architecture based on VMEbus as its platform for integrating COTS and customized equipment. This contributes to the fidelity of its VITAL vision systems, used in fixed-wing and rotary-wing aircraft simulators, for which SSD has received FAA certification.
A five-channel version of the latest VITAL 9 system is to be installed at the U.S. Army’s helicopter pilot training facility at Fort Rucker, Ala. It will provide resolution down to 8 inches (20 cm). Pilots practicing precision, low-level maneuvers will benefit from the depictions of rotor downwash on water, foliage and other terrain features. As a result of time spent in the simulator, transitioning of Army aviators to the Sikorsky UH-60 Black Hawk helicopter requires the pilots to complete just seven to 10 flying hours in the aircraft.
Simulation specialist cueSim not only provides modular procedural training solutions based on commercial equipment, but also uses similar technology to upgrade older-generation, custom-designed equipment. Upgrades and replacements based on PC hardware and software elements often exceed the capabilities of traditional solutions and at much lower cost, the company claims. Such upgrades also are said to reduce maintenance and support costs.
Radstone Technology claims it is ready to meet requirements for more rugged simulators by integrating robust VME-based equipment from commercial and industrial-grade components and supplying it to system integrators. It has elements based on PowerPC processors, such as those used in Apple Mac computers, in the defensive aid subsystem of Eurofighter.
Customers can select from five levels of ruggedization–from added heat sinks for improved thermal tolerance to protection against vibration, shock, heat, electromagnetic pulses, and ‘g’ acceleration.
Radstone also belongs to the Component Obsolescence Group (COG), an industry collaboration that also includes leading systems companies. COG considers buy-ahead, technology insertion, and other strategies for coping with the rapid rate at which the commercial PC industry spews out new products.
"As part of our product life-cycle management service, we offer customers a set of options," says Hugh Lawrence, Radstone’s European business development manager. "We notify them as early as possible of components that are likely to become obsolete, and we give them time to consider whether they want to make an outright last-time buy now, a deferred lifetime buy, or to upgrade by inserting a later technology. Should they decide to buy current-standard components ahead, we will offer environmentally controlled storage facilities."
As technology advances, the use of a VME-based architecture with open standard software facilitates rapid insertion of new, improved boards. These can be plugged in as direct replacements. Functional and other changes are accommodated through modified software interfaces. Backward compatibility ensures that existing applications can be loaded onto the new boards.
A relatively new trend is embedded training (ET), involving simulation systems that are part of, or "embedded" into, existing subsystems. ET systems are designed to provide cost-effective and realistic simulation in a deployed environment–particularly beneficial for the military in combat. COTS technologies for embedded systems include Intel-based single board computers, and 3D Graphics and Sound Blaster audio products for these applications, says Frank Willis, vice president of business development, with SBS Technologies Government Group. Unlike simulators in stationary, controlled environments, however, these products are usually ruggedized and conduction-cooled, enabling them to operate in severe temperature, shock, and vibration environments.
An additional benefit, as the battlefield becomes more network-centric, is that field commanders will be able to conduct maneuver training through wireless communications, using ET to conduct rehearsals before executing "real world" missions.