Features - Technical

MAY 9, 2000

Head-up Displays (HUDs)

BY PETER WRIGHT

Head-up displays (HUDs) are now proven and fully accepted technology for use in military and commercial aircraft, but have not yet found a permanent place in either road or racing cars, although Cadillac have offer one, based on Hughes technology, for some years.


Head-up displays (HUDs) are now proven and fully accepted technology for use in military and commercial aircraft, but have not yet found a permanent place in either road or racing cars, although Cadillac have offer one, based on Hughes technology, for some years. The principle of projecting information into the pilot's or driver's field of vision so that he can keep his head out of the cockpit and concentrate on what is going on outside it, makes lots of sense in certain circumstances. When a pilot is flying near the ground, particularly when landing, or during visual engagement with an adversary, or when keeping a close eye on a refuelling hose and tanker aircraft, the avoidance of having to look down into the cockpit and refocus onto the panel displays to acquire essential flight information, is a major safety feature. For a HUD to be of real value to drivers, they must need the information that is projected into their field of view, and not be distracted or annoyed by it.

Aircraft HUDs project images onto a half-mirrored glass panel, through which the pilot's outside view is hardly degraded, and they are reflected onto the retina, focused at infinity i.e. roughly where the pilot's eyes are focused. GM's system used the windscreen, with a hologram of a mirror etched into it, as a reflective surface. Speed and key warnings are the main information displayed.

In the early 1990s, both Team Lotus and Williams Grand Prix experimented with a Frazer Nash Technology system, based on GEC-Marconi technology. A tiny LED projector and half-mirrored glass panel, almost a miniature aircraft HUD, were fitted to the inside of the driver's helmet, in front of one eye. Various types of information display were tested, such as RPM warning lights, gear position, master warning, and the drivers didn't like any of them. The safety implications of having hardware mounted in front of their faces, instead of padding, didn't excite them much either. Anyway, as is well known, drivers never look at their dash panels unless specifically asked to; all the information is collected and telemetered to the Pits. Ferrari has also experimented with a system in recent times, but does not appear to be racing it.

However, in the recent furore over traction control cheating, and the proposed ban on Pit Lane speed limiters, it looked for just a moment that the HUD's day had come. If drivers couldn't have automatic systems to stop them speeding in the busy and dangerous Pit Lane, using a HUD to inform them of their speed looked like a very good idea. Unfortunately for the HUD protagonists, the FIA relented and allowed the limiters to remain, albeit with the rear light flashing and the refuelling flap open when in use. SomedayÉÉ.