The AS-90 ("Artillery System for the 1990s"), known officially as Gun Equipment 155 mm L131, is an armoured self-propelled howitzer formerly used by the British Army and subsequently donated for use by the Ukrainian Army.
It can fire standard charges up to 24.7 km (15.3 mi) using 39-calibre long barrel and 30 km (19 mi) with 52-calibre long barrel. The maximum rate of fire is 3 rounds in 10 seconds (burst); 6 per minute for 3 minutes (intense); and 2 per minute for 60 minutes (sustained).
Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mortar, and self-propelled rocket artillery. They are high-mobility vehicles, usually based on continuous tracks carrying either a large field gun, howitzer, mortar, or some form of rocket/missile launcher. They are usually used for long-range indirect bombardment support on the battlefield.
In the past, self-propelled artillery has included direct-fire vehicles, such as assault guns and tank destroyers, which were typically well-armoured vehicles often based upon the chassis of a tank. In lieu of the standard tank's general-purpose main gun that fired both high-explosive and anti-tank ammunition, direct-fire vehicles had specialized roles, with assault guns providing close fire-support for infantry and tank destroyers mounting an anti-tank gun to take on enemy armour.