Delivering the Message at 30,000 Feet

Data presentation on military aircraft

by Richard Mandel

The F-16 and Seaking maritime helicopter pictured here use graphics controllers to help convey critical information to pilots

There are several issues important to flying a military mission today, two of which are:

In the case of the latter, it is important to remember that not all military aircraft are either fighters or cargo transports. Much of today's airborne work involves surveillance and preemptory action, as well as battlefield management by flying platforms such as the AWACS. These flights are made with crew members in the avionics suite solely to interpret the deluge of information that's been acquired by sensor arrays, then digitized and delivered to the various appropriate crew stations. (Of a crew of 21 on the Boeing 767 AWACS, two are flight crew, the rest are mission specialists.) The variety and volume of the data requires a system that can present information in a clear, concise fashion, yet be easy enough to use by someone without a four-year degree in Information Technology or Engineering.

PMC-700 graphics controller

Canadian manufacturer DY 4 Systems Inc., Kanata, ON, produces embedded devices and software that, amongst other applications, have been used in aerospace and military applications. Their latest product, the PMC-700 graphics controller, is for HMI-critical applications such as cockpit primary flight and digital map displays. Used in a variety of military vehicles, the board is capable of rendering 2D and 3D information, plus has functions for video capture and overlay, support for legacy-interlaced displays, and anti-aliasing capabilities. Designfax recently discussed airborne information displays with DY 4 principal engineer Steve Gourley.

DFX: Would the PMC-700 controller be used on commercial aircraft, as well as military?

SG: No, it's primarily for mil applications. Commercial applications generally require flight safety critical validation, largely for failure accountability. The software required to draw, for example, objects on the screen, must be quite simple in order to be (commercially) certified, whereas the stuff we're doing is calling for OpenGL and XWindows (Windows in a Linux or UNIX environment).

DFX: Are these displays used elsewhere besides the crew stations?

SG: They can be used anyplace on the platform, whether it's an avionics platform, a tank or a jeep. The types of displays used may include touchscreens, but more often it's bezel-button style, similar to ATM bank machines, where the function of the button is printed on the adjoining screen. This is easier to use, particularly in the cockpit where at issue is "pilot overloading." Also, touching the screen involves covering up the display, however briefly, and more so when wearing gloves, as with biohazard gear.

DFX: When you refer to pilot overload, is the ability to display 3D images designed to help remedy this?

SG: The pilots mainly receive 2D information, although there is a kind of 3D image projected onto the heads-up display, depicting lines proceeding into the distance that suggest a "highway in the sky." There are also experiments to display synthetic data, giving the pilot 3D terrain information if he is flying through, say, the Grand Canyon. Our card will probably be involved in those next-generation systems as they develop for aviation, as well as in tanks and other vehicles.

Mission specialists in the avionics suite of the Boeing 767 AWACS

Some of our cards, with their Pentium chips running Windows operating systems, work very much like ordinary PCs. One item that's less common for a PC environment is the capability to show video -- usually night-vision FLIR or something similar. The display system is required to show the video and overlay other graphic information on top of that at the same time.

We often find that people want to change parts of the system -- they won't change the displays since it may be too difficult to change the "glass" in the cockpit, so they instead replace a box in the back of the plane. We find ourselves having to support rather old technology, many times interlaced with RS170 video lines. Many sensors still use that format, so we have to accommodate both the input and output of interlaced video to drive the older displays and sensors.

DFX: Does the PMC-700 board carry a Pentium chip?

SG: No, it's designed to be part of a PCI bus.

DFX: Is that different from an aircraft's 1553 lines?

SG: That's just mainly for box-to-box communication, relatively low bandwidth. But the cables are a concern -- as I mentioned, the computers are in the back of the aircraft with the displays up front. As the cable lengths become too great, the signal begins to degrade. The designers have explored fiber-optic and high-speed serial lines to resolve this -- this is why the PMC-700 now has the ability to output digital data, which can be routed through optical or serial lines.

Circa 1940, Popular Mechanics	Today, aboard the Boeing 767 AWACS
Then and Now: HMI-critical applications such as cockpit primary flight and digital map displays have come a long way since the 1940s

DFX: How many displays can be controlled by a PMC-700?

SG: Typically, it's one board per display, but it's possible to drive two, with the second somewhat degraded compared to the first. Depending on the application, this could be acceptable. To conserve space and weight, the VME boards are designed to fit two onto a single PowerPC or Pentium card. And we're looking ahead at increasing that number to four per card, driving four displays from one card.

DFX: How long does it take to develop a board like the PMC-700, and to get it up to mil-spec?

SG: The answer to that is "a year," but that's a little misleading. Part of the difficulty today is finding a suitable graphics chip -- the major problem being that the people making the best graphics chips won't speak to us because our volume is too low. So, we have get their attention somehow, so that we can access their software for optimizing the codes.

DFX: Ultimately, Steve, what other vehicles use displays handling this complexity of information?

SG: Everything from fighters to helicopters to patrol aircraft, plus vehicle like tanks and troop carriers. In a Bradley tank, for example, the troops on board are in a protected environment, and are sometimes required to maneuver on instruments alone, rather than looking through slots, because of chemicals or other weapons.

There's all kinds of applications, but it's really like a desktop PC -- it's all very flexible. The proprietary difference lies, again, in it's ability to do interlaced outputs. Most high-performance graphics chips today don't support anything but non-interlaced graphics. Command/control is less complex, less demanding an environment for data, and that can be open to commercial-grade cards. Cards like ours are for driving large displays in a station that has need for full color, video and 3D.

For more information:

Circle 420 - DY 4 Systems Inc., or connect directly to their website via the Online Reader Service Program http://www.1rs.com/006df-420