PGAAM Ollnóva MANPAD

From Atlas
PGAAM Ollnóva

Type Man-portable air defence system
Place of origin Astronea
Service history
In service 1992-present
Used by Astronean Armed Forces
Production history
Designer Arlogh Ballistics
Designed 1983-1989
Manufacturer ACC Defence Division
Unit cost $14,000
Produced 1990-present
Specifications
Length 1,368 mm (53.9 in)
Crew 1

Caliber 22mm x3
Muzzle velocity 1,372 m/s (4,500 ft/s)
Effective range 7,000 m (7,700 yd)

Guidance
system
SACLOS and SALH

The PGAAM (precision guided anti-air munition) is a high velocity air defence missile system capable of engaging helicopters and other low flying aircraft. The weapon fires a unique warhead that uses 3 submunitions to increase the probability of successfuly hitting the operator's target. These dart-like submunitions are packed with direct impact fuzes and fragment upon contact with a target, propelling shrapnel at incredibly high velocities. The PGAAM gains is designated the PGAAM "Ollnóva" in Astronean service, Ollnóva meaning supernova in English, due to the speed and ferocity of the submunitions launched from the weapon.

The PGAAM does not use conventional IR tracking to detect targets, instead using laser beam riding technologies which make the missile difficult to jam with conventional countermeasures such as flares and ECM. No lock on is required with the PGAAM; as soon as a target presents itself, the operator can pull the trigger and track the target optically.

On board laser tracking means that the operator only has to aim in the direction of the aircraft and the PGAM warhead will propel itself automatically to the target. The missile itself moves at speeds of over Mach 4, and upon reaching the target, will fire off its 3 independently tracked submunitions. This creates a wider area of effect on the target, improving the chance to hit. The beam riding system itself using a low signature laser, making it nearly undetectable by onboard enemy RWR systems. Useful for engaging "pop up" targets which only present themselves for a short period of time. It is currently fielded across the AAF.

Design[edit]

The PGAAM is transported in a sealed launch tube. This tube is attached to an aiming unit for firing. The operator tracks the target using the aiming unit's optically stabilized sight. The process of tracking the target allows the aiming unit to compute the right trajectory to bring the missile together with the target. The operator can indicate wind direction to the unit and, in the case of a long range target, provide superelevation. When the initial tracking is complete, the operator fires the missile by pressing a button.

The missile then fires the first-stage rocket motor, which launches the missile from the tube – but burns out before leaving the tube to protect the operator. Four hundred meters away from the operator, when the missile is a safe distance away, the second stage fires, which rapidly accelerates the missile to burn out velocity of more than Mach 4. As the second stage burns out, three dart sub-munitions are released.

The dart housing is made from a tungsten alloy. The darts are each 396 millimetres (15.6 in) long with a diameter of 22 millimetres (0.87 in) and weigh about 900 grams (32 oz). Around half the weight of each dart, approximately 450 g (16 oz), is its explosive charge, detonated by a delayed-action, impact activated fuze. Each dart consists of a rotating fore-body with two canard fins attached to a non-rotating rear assembly which has four fins. The rear assembly of each dart also houses the electronics that guide the missile, including a rearwards facing sensor.

The darts do not home in on laser energy reflected from the target but instead the aiming unit projects two laser beams which paint a two dimensional matrix upon the target. The lasers are modulated and by examining these modulations the sub-munition's sensor can determine the dart's location within the matrix, the dart is then steered to keep it in the centre of the matrix. The sub-munitions steer by briefly decelerating the rotating fore-body with a clutch. The front wings then steer the missile in the appropriate direction. The three sub-munitions fly in a formation about 1.5 meters in radius, and have enough kinetic energy to manoeuvre to meet a target evading at 9 g at 7,000 meters.

Earlier laser guidance systems used a single beam that had to be kept on the target at all times, the missile homing in on laser energy reflected off the target, if it moved off the target, the reflection would end and guidance would be lost until the target was regained. The problem could be reduced by making the laser's beam wider, but only at the cost of lowering accuracy and reducing the amount of energy being reflected. The PGAAM's system allows for the beam area to be much larger than the aircraft while retaining pinpoint accuracy.

On impact with the target, a delayed action fuze is triggered. This gives time for the projectile to penetrate the target before the explosive warhead detonates. The tungsten housing is designed to fragment and produce maximum damage inside the target.