This invention relates to gun fire control systems and, more particularly, to a computerized control system for aiding a gunner, while providing simplified construction in that a telescopic sight and laser range finder are fixedly secured in alignment with the gun barrel or other launcher of projectiles.
During the firing of a projectile from a gun, the direction of travel of the projectile differs from the direction in which the gun is pointed due to the forces of gravity, air resistance and wind. Therefore, the gunner must sight on a target along a line called a sight line which differs from a line, known as a gun line, along which the gun points. In the case wherein a target trajectory would carry the target across the gun line, the gun must be oriented such that the gun line leads the target and points ahead of the sight line to allow for the time of flight of the projectile. Thus, there is an angular divergence between the gun line and the sight line.
The angular divergence has a component in the elevation plane and a second component in a lateral or azimuthal direction normal to the elevation plane. The amount of angular divergence in elevation and azimuth depend on target range, the speed of relative motion of the target with respect to the gun, as well as on other factors including gravity, air resistance and wind.
Due to the divergence between gun line and sight line, the gun and the sight normally require separate two-axis positioning systems and separate two-axis position sensing system which entail costly hardware and increase the complexity of such gun fire control systems.
In most gun fire control systems, the angular divergence between sight line and gun line is produced by a servomechanism positioning a reticle in a sight or a mirror in a periscope. A problem exists in that such construction increases cost and complexity of equipment.