VistaNav brings SVS to its electronic flight bag

 - November 8, 2006, 4:57 AM

What if you had an electronic flight bag (EFB) that doubles as a backup multifunction display with airspeed, altimeter, attitude and heading indicators in case your glass-panel cockpit goes completely dark on a stormy night? And even better, what if that backup system could guide you down an approach to minimums with an intuitive highway-in-the-sky (hits) path overlaying a 3-D synthetic picture of the outside world with real-time weather and traffic display?

These are exactly the questions engineers at Mercury Computer Systems in Chelmsford, Mass., asked, and the system they developed in response does all that for about $7,000 including optional features. VistaNav is more than an EFB with moving-map software guided by an external GPS. “I don’t like the term EFB,” said Jeff Simon, VistaNav senior product manager. “An EFB has no nav functions; it’s the equivalent of your paper flight bag but easily updated. Technically we are an EFB because we have approach plates, but we view VistaNav as a synthetic-vision product; it’s a navigational aid.”

VistaNav’s hardware consists of a Motion Computing LS800 tablet computer, an external inertial navigation unit (INU) that communicates wirelessly via Bluetooth with the LS800, a GPS antenna and a fan-cooled mount for the LS800. The LS800 can be fitted to a yoke mount or–using the fan-cooled mount–suction-cupped to the windshield and positioned for easy pilot viewing without blocking the view through the windows. The INU is a solid-state gyro system that drives VistaNav’s MFD and delivers GPS information. Optional equipment includes XM satellite weather and Xaon XRX traffic awareness system.

Like other programs with nav data and computer-based moving-maps, VistaNav cannot be used for primary navigation and is offered solely as an advisory system. Mercury said its goal with VistaNav is not to show the world how much functionality can be crammed into a relatively small and portable package. Rather, said Simon, “Our goal is to increase safety and change the way people fly their aircraft. We believe synthetic vision is a revolution in navigation.”

Synthetic Vision
The heart of VistaNav is the system’s 3-D synthetic vision display. Synthetic-vision systems (SVS) offer pilots a view of the outside world unencumbered by clouds or other obstructions to vision. The quality of any SVS depends not only on the power of the computer system it runs on but to an even greater extent on the content of its terrain and obstacle database. With its long background serving defense contractors, including UAV manufacturers, Mercury, working with a German university, has developed a detailed and data-rich terrain database, said Simon.

As they would with any moving-map system, pilots start using the VistaNav by inputting a flight plan. The LS800 doesn’t have a touch screen, so the pilot uses a stylus to activate items on the screen or select letters from a virtual keyboard when
looking for a particular airport. The LS800 has built-in wireless networking, so users can also use VistaNav at Wi-Fi-equipped FBOs to check weather, update the terrain and nav database, file flight plans and so on.

While taxiing, the pilot can monitor aircraft position on the airport using NACO airport
diagrams. During flight, pilots can view the VistaNav display three ways, in 2-D, 3-D or split 2-D/3-D mode.

The 2-D mode is the typical seen-from-above moving-map view, augmented in the VistaNav with terrain awareness display. In the 3-D mode, VistaNav shows the synthetic outside view complete with terrain, obstacles, airports, navaids and highway-in-the-sky. In the split mode, the image on the top is presented in 2-D while the image on the bottom is presented in 3-D.

When the airplane is flying to a specific point or using VistaNav’s built-in vector system, the system displays a hits path for the pilot to follow. The hits path looks like a road made of alternating purple and clear rectangles with a box through which the airplane should fly to stay on track. A white predictor circle shows where the airplane will be in nine seconds.

To stay on the programmed flight path, the pilot simply keeps the predictor circle in the center of the hits box. For precision and nonprecision approaches, the hits track turns into a tunnel that the pilot follows down to decision height or minimum descent altitude. In cruise, the 3-D synthetic view shows navaids, airports and obstacles as sticks that rise out of the earth with small information icons that appear to sit at the pilot’s eye level.

To get from the last en route point to the final approach fix, VistaNav can draw a curved hits path. A planned feature is to allow the user to select a specific initial approach fix, according to Simon.

For in-flight emergencies such as a power loss, VistaNav takes the “nearest airport” feature to a new level. Not only does it show the way to the nearest airport with a hits path, but it also tells the pilot which airport is reachable given the glide capability of the airplane (after the loss of power) and the existing terrain.

Safety Enhancements
VistaNav also has a simulation function, so pilots can practice on the ground. In the air, pilots can use simulation to practice maneuvers at altitude that would be too dangerous near the ground. For example, in simulation mode a flight instructor could program a runway 3,000 feet in the sky then, using the 3-D synthetic vision mode, have the student practice takeoffs followed by power loss. [To demonstrate the almost certain futility of trying to return to the runway. –Ed.]

VistaNav is designed to make flying IFR easier for pilots who don’t fly in the system frequently and also to offer a safe backup system for pilots flying glass cockpits. One Cessna pilot was pleased to have VistaNav on an IFR flight in IMC during which his glass panel went dark. Although he didn’t have his VistaNav set up already, he was able to pull it out, turn it on and land safely, according to Simon.

An advantage of a system such as VistaNav is that its lack of FAA approval means that Mercury can add updates at any time instead of having to go through the cumbersome and lengthy FAA-approval process. Mercury is, however, working on certifiable panel-mounted systems offering functionality similar to VistaNav’s.