1. Field of the Invention
The present invention pertains to a system for restoring the visual environment of a pilot in an simulator.
The visual environment of a pilot includes the following main images:
moving images of the scene outside, normally seen in flight by the pilot through his cockpit canopy, comprising the sky, ground and moving objects such as aircraft, aerial and land targets, missiles, effects due to firing, etc.; PA1 moving images from the fixed sight unit and the movable sight unit (headset sight unit); PA1 moving images from the different instruments located chiefly on the instrument panel inside the cabin. PA1 keeping to the apparent size and relative position of each of the elements of these images with respect to the cockpit and to the usual references of the pilot such as the fuselage horizontal reference (FHR) axis and the sight unit image reference axis etc., PA1 keeping to the dimensions of the field of vision that the pilot can explore in turning his head as in reality. The limits Of this field of vision are illustrated in FIG. 1 which is an example defining the boundary between the zone 10 observed through the cockpit and the zone 11, hidden by the cockpit including the instrument panel.
2. Description of the Prior Art
There are two types of prior art simulators used to restore an environment of this type: "spherical simulators" and "standard trainer" type simulators.
A "spherical simulator" has a sphere with a diameter of 8 to 12 meters (FIG. 2), the internal surface of which forms a wide-angled, concave, reflecting screen 20. A reproduction of the aircraft or helicopter cockpit 21, in which the pilot is placed, is located at the center of the sphere.
The view of the ground, and that of the sky, are simulated, for example by two images projected on the sphere and produced by a projection device 22, placed above the cockput and comprising two "fish-eye" type lenses oriented in opposition and located on either side of the center of the sphere
The rolling and pitching effects are obtained by the rotation of the two fish-eyes around the center of the sphere.
The images of the moving objects are obtained by projection systems 22 placed above and behind the cockpit.
The image of the fixed sight unit is presented by an optical device 24 installed in the cockpit.
A variant (FIG. 3) of this spherical simulator uses two fixed fish-eye lenses 30 and 31, placed on either side of the cockpit, outside the pilot's range of vision. These two fish-eyes project two juxtaposed images 32 and 33 on the screen. These images 32 and 33 come from two light valve TV projectors connected to a synthetic image computer 34 generating the sky and the ground, located before and behind the cockpit, in taking into account the effects due to changes in altitude and position of the simulated aircraft.
The spherical simulator and its previously described variant present all the images of the scene outside, the fixed sight unit, the instrument panel etc., while respecting, as in reality, the apparent size and the relative position of each of the elements of these images with respect to the cabin and to the usual references of the pilot, and while respecting the field of vision illustrated by FIG. 1.
A simulator such as this works very well, but is very expensive.
The second device, of the "standard trainer" type (FIG. 4), restores the pilot's environment by using sub-units such as a television screen 40 or a projector of a standard type found in the market presenting, in particular, the images of the scene outside 41 on a plane screen without respecting, unlike the spherical simulator, the apparent size and relative position of each of the elements of the outside scene with respect to the cockpit and to the pilot's references.
Thus, the image of the frontal outside scene which, in reality, covers a solid angle of 2.pi. steradians, is presented by means of the plane screen beneath a solid angle 41, smaller than 0.5 steradian, depriving the pilot, notably in his peripheral field of vision, of the references needed to carry out a mission.
This second type of simulator costs little but is not satisfactory from the viewpoint of the realism with which the visual environment is restored.
An object of the present invention is a system to restore the visual environment of pilot in a simulator, a system that costs little, is easy to reconfigure and restores a visual environment that is as realistic as possible, in meeting the following constraints: