Posting head high

The posting head high consists in superimposing necessary informations with piloting, the Navigation or the realization of the mission on the external environment. It makes it possible to the pilot to supervise his environment at the same time as furnished informations by its instruments.

The French terminology uses the term sight head high , translation of English head up display . The technicians use the abbreviation CTH for collimator head high or VTH for Visualization head high.

Problem arising

In a fighter the pilot must supervise his environment at the same time (avoidance of the obstacles during the flight at low altitude and planes enemy) as it must ensure piloting, the navigation and the realization of his mission. The eye of the pilot must thus constantly adapt his vision on the external landscape (ad infinitum) then on its instrument panel (a few tens of centimetres) what is source of tiredness and can also lead the pilot to be unaware of an significant event.

Solution

By laying out a transparent mirror between the head of the pilot and the canopy one can project ad infinitum collimated images there. These images are superimposed on the landscape and thus make it possible to the pilot to supervise at the same time his environment and the abundant data by its Instruments.

The ice is tilted with 45° and the field of vision is about 20°.

The most modern systems allow projection several colors and even that of images of television.

Projected information

Projected information is worked out by a calculator and, generally, results from a synthesis between several primary information from the instruments. The nature of information is sometimes modifiable according to the phase of the flight: in final stage the pilot can post the firing envelope of a missile in more or in the place of the relative informations to piloting or navigation.

On the commercial aircraft, the HUD is primarily used to present relative informations to the environment such as track of Atterrissage masked by the Brouillard.

Future

The cost, the obstruction and the weight of these systems made them hold up to now for the situations where the pilot is particularly solicited. With the miniaturization of the calculators and the increase in their capacity at constant cost the display systems head high could have applications in wider fields, even general public such as the Automobile S top-of-the-range the following the example of Citroen C6.

In the military aviation, it should be noted that the future F-35 will have " dépassé" this technology, tactical information posting themselves directly on the visor of the Helmet of the pilot, thus being used as Sight. Several other apparatuses have such helmets under development.

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