Virtual worlds for military simulation
In a long and very well documented article, Military & Aerospace Electronics (M&AE) tells us about recent improvements in military simulations due to advances in display technology, data processing and software. The article points out that military designers are at the same time increasing their supercomputing facilities while streamlining the databases needed to simulate complex vehicles such as helicopters or enable the synchronization of the many simulated elements. While the original article looks at all kinds of technology improvements, this overview is focused on specific advances in display technology.
Obviously, these simulations need to be precise enough to earn armed forces' confidence.
"The name of the game is 'How real is the immersion?'" says Frank Deslisle, vice president of engineering and technology at the L-3 Link Simulation & Training segment in Arlington, Texas. "Our key challenge is to replicate scenarios and represent the physical world in the display environment."
Simulation designers at Link achieve that goal through four technology areas: the display mechanism such as a screen or prism; image generation and rendering; a fixed-environment database including terrain, roads, and buildings; and a dynamic behavior database, such as weather, humans, and explosions.
But it's difficult to find a compromise about the size for such simulators. While the best quality simulations need to transfer a full cockpit inside a 30- or 40-foot diameter dome, the military would prefer portable systems. So the engineers at Link have built a smaller version of their full domes.
Engineers at Link now make a smaller version of the dome simulator called the SimuSphere visual system display. The design is a dodecahedron geometric shape, built with pentagonal facets that are each the same shape, size and distance from the pilot’s eye point. Customers can build this modular system with three, five, or seven facets for partial immersion, or nine facets for a full 360-degree view.
Below is a photo of the L-3 Link SimuSphere visual system display (Credit: L-3 Communications). And here is a link to a larger version (933 KB).
These systems are operational today, at a price of about $500,000 each, but are still not portable. So the engineers at L-3 Link have developed new advanced helmet mounted displays (AHMDs), which should enter production in the first quarter of 2006.
The AHMD offers 100-degree horizontal by 50-degree vertical field of view, with a 30-degree binocular overlap region that induces a sense of immersion. It also has 60-percent see-through capability so users can view their cockpit controls or read maps in high ambient lighting.
Below is a photo of the latest L-3 Link advanced helmet mounted display (Credit: L-3 Communications). And here is a link to a larger version (1.23 MB).
And here are few more details about this system.
Another challenge was to reduce latency or “smearing” by picking the best liquid-crystal displays (LCDs). "Pilots turn their heads fast, and if they see smearing, they’ll walk out of the simulator," Deslisle says.
Finally, each system is tethered with a thin fiber-optic cord to a server, making the entire machine more portable than previous simulators, he says. "Now they can do training and mission rehearsal en route, or even in theater," Deslisle says. "They are not restricted to a training center," he says. "That’s the goal, and now the technologies are converging on that."
For your viewing pleasure, you also can visit the L-3 Link photo gallery.
And for more information about how the military forces are using databases and supercomputers, please read the full M&AE article.
Sources: Ben Ames, Military & Aerospace Electronics, November 1, 2005; and various web sites
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