Aiming point

In field artillery, accuracy in indirect fire relies on the use of aiming points (APs). These points provide a reference for aiming guns in the correct horizontal direction (azimuth). Until the 1980s, APs were essential for indirect fire artillery, as well as for mortars and machine guns firing indirectly. An AP must be sufficiently distant from the gun to account for movement during firing, which can shift the gun's position and alter the angle to the target. A distance of several kilometers is typically sufficient. The AP should be a distinct feature, such as the edge of a building, but this poses challenges in featureless areas or poor visibility.

Historically, early APs included pairs of aiming posts placed about 50 meters from the gun. During World War I, the French introduced the collimateur, while the British developed the parallescope, a horizontal mirror used to aim via reflection. In the 1950s, the prism parallescope replaced earlier versions, and in the 1970s, the U.S. reintroduced a modern version of the collimateur. Infra-red beacons saw limited use during this period.

By the 1980s, systems like the U.S. Multi-Launch Rocket System eliminated the need for APs by using gyroscopic orientation. Similar technologies were later adopted by other artillery systems, including towed guns. Originally, APs were used to orient guns quickly, with "Gun Aiming Points" (GAPs) providing supplementary references. Many armies recorded multiple GAPs, but these became obsolete with advanced orientation systems.