Honeywell demo shows fused SVS/EVS views

 - October 27, 2010, 6:34 AM

Honeywell has given the aviation world its first glimpse of a cockpit technology that developers say will change the way future pilots aviate by combining the views of a synthetic-vision database of obstacles, topography and airports with a forward-looking infrared camera.

Honeywell wasn’t the first avionics manufacturer to explore such a concept–and the company concedes that it probably won’t be the first to bring the technology to ­market–but nonetheless it relished the opportunity to be the first to publicly demonstrate the merging of ­synthetic-vision system (SVS) and enhanced-vision system (EVS) visuals on a business jet primary flight display.

Honeywell chose to reveal its progress on the developmental enhancements to its SmartView SVS by inviting aviation journalists on a series of nighttime demonstration flights in mid-September between Arizona’s Phoenix Deer Valley Airport and Prescott Ernest A. Love Field. Flown in Honeywell’s Cessna Citation Sovereign captained by company chief test pilot Jary Engels, the sorties gave the trade media their first opportunity to see such an SVS/EVS presentation in the cockpit of a real airplane.

While Honeywell tempered expectations for the demonstrations with the admonition that the developmental technology is still probably five years from reaching the ­market, the fused SVS/EVS view that ­journalists saw on the demo flights seemed enticingly close to becoming a flight-deck-ready upgrade to Honeywell’s Primus Epic avionics system. Hundreds more hours of flight testing are needed for initial certification, and even more work lies ahead before Honeywell can realize its goal of using the technology to obtain lower landing minimums for properly equipped airplanes, but the work done so far shows immense promise.

3-D Virtual View

By itself, Honeywell’s SmartView SVS gives pilots a compelling 3-D virtual look at the world ahead of the airplane, complete with guidance cues and terrain shading in colors that mimic VFR sectional charts. That presentation becomes far more convincing–and reassuring–once the EVS view is added in the center of the primary flight displays. Using special software algorithms, the EVS image from a Kollsman IR camera mounted in the nose is shaded in the same colors as the resident SVS terrain in the background, while also being “blended” with the SVS view. The technique helps to merge the SVS and EVS views into a single coherent picture that makes every flight the equivalent of a bright, sunshiny day.

As we descended over northern Arizona on one of the flights, mountain peaks that could not be seen out the windshield because of the darkness were easily discernable on the PFD. The SVS and EVS views of terrain almost always matched up perfectly as mountains entered and exited the EVS portion of the display–including the subtle color shifts from brown to green as the terrain rose and fell.

When the images didn’t align properly, it was usually because the real sky in the distance was darker than the virtual blue sky on the SVS display or in areas where the database’s interpretation of terrain did not mesh perfectly with the real world outside. Still, during the majority of the demonstration flights, the SVS and EVS worlds matched one another surprisingly well. The biggest difference on the EVS portion of the display was the ability to clearly make out roads, rivers and other ground features that were not present in the SVS view.

On approach the technology seemed even more impressive. As the pilot reached to pull down the gear handle, the view on the displays automatically shifted, decluttering the flight path marker to allow more of the EVS view to be seen on the display. Once the airplane was established on final, the landing runway was highlighted by a cyan rectangle with a cyan course line flanked by thicker cyan dashed lines (“Paver stones,” Engels called them), highlighting the final approach course all the way to the runway threshold.

As the Sovereign reached decision altitude, a virtual gray runway marked 22L morphed into (and matched extremely closely with) the real Runway 22L at Prescott Airport that appeared in the EVS window. Unlike the SVS portion of the display, inside the EVS window one could see taxiways, airport lighting (including the VASI) and other aircraft and ground vehicles. Developers say this real-world view on the PFD is what makes SVS/EVS blending such an important safety enhancement.

“The benefits of blending the synthetic view, which we’ve already certified, with a real-world enhanced view using sensor data are pretty obvious,” said Chad Cundiff, vice president of crew interface products for Honeywell. “You can ­imagine if there was a deer on the ­runway or truck driving across how valuable it would be to have that IR view.”  

Once on the ground, the enhanced SmartView presentation changes again, this time expanding the EVS box and turning it gray to provide an improved view for taxiing at night or in low visibility. Many pilots who fly with HUD-based EVS systems say IR technology’s greatest safety benefits come while taxiing at night, especially on unfamiliar airports. Some of those same pilots complain about the limitations of IR-based EVS, one of which is that it cannot see through solid clouds or fog. But because of the way Honeywell blends SVS and EVS views, the technology can be used in clouds. In such cases, the SVS view becomes dominant even in the EVS portion of the display.

One benefit of the SVS/EVS blending technique Honeywell has developed is that it helps pilots easily pick out the height of cloud layers above and below. (Another drawback of IR-based EVS is its inability to detect LED lighting, which is fast becoming the standard at airports around the world.)

The big question now is whether the FAA will someday allow landing credits as it currently does for HUD/EVS operations. Pilots flying with HUD-based EVS are permitted to continue straight-in precision approaches to 100 feet if they can see the runway using the EVS. Honeywell is hoping to obtain a similar operational enhancement in airplanes equipped with SVS/EVS. Cundiff noted that the FAA’s NextGen roadmap calls for the introduction of “equivalent visual operations” (intended to give aircraft VFR ­capabilities in IFR conditions) sometime between 2012 and 2016. Honeywell ­representatives are part of FAA and RTCA working groups now exploring such technologies.

Perhaps the best indication of whether SVS/EVS blending will improve safety and enhance situational awareness came during a portion of the demonstration flight when Engels shut off the SmartView system. The display automatically reverted to the traditional blue-over-brown presentation of an electronic ADI. Invariably when this happens in a high-performance airplane in the mountains at night, the pilots’ immediate reaction is to want the SVS view turned back on–asap. Given the choice of an SVS view or a display featuring blended SVS and EVS, chances are very few pilots would choose the former. “Having that IR view of what’s really outside raises the comfort level at least a notch or two,” Engels said.

Some competitors of Honeywell are working toward similar goals, and at least two of them appear likely to cross the ­certification finish line with blended SVS/EVS products before Honeywell does. Rockwell Collins has been testing a similar concept for use with its Pro Line Fusion cockpit, due for certification in 2012, and Garmin has put SVS/EVS blending high on its wish list for the G1000/G3000/G5000 series of cockpits. Still, given the progress Honeywell has made to date, even if it has to settle for being second or third to market, it won’t be long afterward that pilots of Primus Epic-equipped airplanes benefit from SVS/EVS fusion.

EVS-SVS: Future Present

As a youngster I vaguely recall ­seeing, in comic books or movies perhaps, ­futuristic ­depictions of guidance ­displays in the cockpits of flying travel machines that had the square-jawed commander navigating the ship by using some ­magically generated recreation of the planetscape outside. While wondering how this could possibly be, I sure enjoyed the ­fantasy of an improbable future.

Improbable no more. After ­capturing the accompanying photos of ­Honeywell’s SVS-EVS display on a big repeater monitor in the cabin, I moved forward a few feet and (thanks to ship commander Jary ­Engels) strapped into the left seat of the avionics manufacturer’s ­Cessna Sovereign to try my hand at what promises to be a significant advance in showing pilots what’s lurking out there in the darkness.

The darkness enveloping our ­Sovereign was pierced by the jagged peaks of the mountains around Phoenix, invisible through the windshield but clearly depicted in the moving, pitching, rolling landscape shown on the primary flight display. The seam between the central EVS image and the surrounding SVS image was unobtrusive, and its synthetic and IR depictions of the jagged horizon were for the most part remarkably well blended and aligned. There’s room for improvement in the alignment of the two when the airplane is banked–the IR depiction of the ­horizon was a little lower than that of the synthetic picture–but even this development imagery was literally eye-opening in its ability to transform the ­visual mystery in the blackness beyond the windshield into a moving vista as obvious as if lit by daylight. In the last moments before touchdown, the synthetic trapezoidal image of the runway and its numbers rushing up to meet us aligned perfectly with the “real” IR ­depiction of the remainder of the runway stretching ­toward the horizon in the center of the display.

We already take for granted that ­databases now know every ripple and contour of Planet Earth’s surface and can tell electronics boxes how to paint a ­synthetic motion picture of the landscape unfolding ahead. We also take for granted that the
infrared eye of an ­enhanced-vision system can bring ­clarity and the familiar growing motion of a ­runway threshold to the murky or inky view through the windshield.

Combining the two is an inspired creation by avionics chefs, and–for a prototype presented to the aviation press for the first time outside the confines of its development engineers and pilots–Honeywell’s take on this new blend of visual cues is impressive indeed. This is very clever stuff, and pilots are going to like it a lot