The AS-90 is a lightly-armoured self-propelled artillery piece used by the British Army. It was first delivered in 1993. Its official designation is Gun Equipment 155 mm L131.
The AS90 is used by five regiments of the Royal Horse Artillery and Royal Artillery: 1 RHA, 3 RHA, 4 Regt RA, 19 Regt RA and 26 Regt RA, replacing the 105 mm FV433 Abbot SPG, the M109 155 mm SPG or the FH-70 155 mm towed gun.
AS 90 was designed and built by the Armaments division of Vickers Shipbuilding and Engineering (VSEL, owned by BAE Systems since 1999), who provided 179 vehicles from 1992 to 1995 at a cost of £300 million.
During 2008-09 AS90 underwent a capability enhancement program. This mostly involved replacement of electronics.
In 2002 BAE Systems were contracted to upgrade 96 British Army AS90s to a 52 calibre gun to push the unassisted range to 30 km and with long-range ERA ammunition to 60 to 80 km. However, due to the inability of the selected bi-modular charge system from Somchem of South Africa to meet the requirement for insensitive munitions this project was terminated.
AS90 started in the mid-1980s as a private venture on the ‘gamble’ that the tri-national SP70 would fail. When this duly occurred, the Ministry of Defence (MoD) issued a cardinal point specification on one page for a new 155 mm SPG. Four tenders were submitted, and AS90 was the only offer that was not ‘brochureware’. The MoD was also required to consider the US “Paladin”, an upgraded M109 howitzer.
The MoD is investigating a proposal from BAE Systems to “up gun” the Royal Navy’s main shipboard gun armament, the 4.5 inch Mark 8 naval gun, to accept the 155 mm gun barrel and breech from the AS-90. This would introduce a common gun calibre for the British Army and Royal Navy, helping with ammunition logistics, and encouraging joint Army-Navy development of extended range and precision guided shells.
In 1963 certain NATO nations, including UK, agreed a Ballistics Memorandum of Understanding for a 155 mm 39 calibre ordnance and a baseline projectile with the shape used for the US M549 rocket-assisted shell. The AS90 uses a conforming 39 calibre barrel which fires the L15 unassisted projectile out to a range of 24.7 km. However, this was a new design of ordnance and uses a split sliding block breech with Crossley obturation, instead of the more usual screw breech, to permit bagged charges (no metal cartridge cases). The breech mechanism has a primer magazine holding 18 primers.
It is fitted with an auxiliary power unit to eliminate the need to run the main engine to keep the batteries charged while stationary; electrical servos drive the automated elevation, traverse, magazine, shell transfer arm
and loader as well as power for electronics and communications.
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– Modified for desert use. Thermal protection for crew and extra cooling for engine and machinery. Tracks adapted for reduced wear in sandy conditions.
– Basically the AS-90, but fitted with the 52 calibre length gun. This project was terminated due to non-compliant propelling charges.
Haubicoarmata “Krab” – (eng. Howitzer-cannon Crab) Licensed “Braveheart” turret on a Polish chassis UPG, with modern “Azalia” BMS. Designed and integrated in Poland, by Huta Stalowa Wola and WB Electronics. As of early 2007, two Krab (“Crab”) prototypes are built, and successfully completed all required evaluations and state acceptance trials. Order for 48 of 80 projected units for Polish Armed Forces is expected in 2008. Due to the use of a modified T-72 chassis the Indian Army is interested in this design.
The vehicle is fitted with an autonomous navigation and gun laying digital reference unit (DRU) mounted on the trunnion. All main turret functions are controlled by a Turret Control Computer (TCC) with control and display units for the No 1 (Detachment Commander), No 2 (loader) and No 3 (layer). The combination of the DRU, TCC and powered laying controls provide autolaying. Every gun is fitted with a radar Muzzle Velocity Measuring Device. Reversionary mode laying uses deflection laying via the direct fire sight.
The gun can be brought into action fully closed down, the barrel can be clamped and unclamped from within the vehicle. Into and out of action times are less than 1 minute.