Patriot Air Defence System

PATRIOT air defence system came into prominence during
the 1991 gulf war as a defence against IRAQ’S SCUD missiles

Patriot is a long range, all altitude, all weather air defence system to counter tactical ballistic missiles, cruise missiles and advanced aircraft. Patriot, designation MIM-104, was designed and produced by Raytheon Missile and Air Defence Systems Division in Massachusetts and Martin Marrietta (now Lockheed Martin) at Orlando, Florida.

MISSILE

The missile has approximate dimensions of 520 centimetres body length and 40 centimetres body diameter. The missile is equipped with four delta shaped fins, fin diameter approximately 85 centimetres.

The missile round consists of the missile in a rectangular shaped combination shipping/storage/firing container made by Lockheed Martin. The Certified Missile Round requires no testing or maintenance in the field and the storage life with one restoration is 30 years.

Behind the cone shaped radome at the head of the missile is the Terminal Guidance Section. The Patriot missile is equipped with a track-via-missile (TVM) guidance system. Mid course correction commands are transmitted to the guidance system from the Engagement Control Centre which is a mobile ground control centre.

The target acquisition system in the missile acquires the target in the terminal phase of flight and transmits the data using the TVM down link via the ground radar to the Engagement Control Station unit for final

course correction calculations. The course correction commands are transmitted to the missile via the Missile Track Command Uplink. A Control Actuator system is situated at the tail end of the missile behind the propulsion system.

The high explosive 90 kilogrammes warhead is situated behind the terminal guidance section. Propulsion is provided by a single stage solid fuel rocket motor behind

the warhead. The range of the missile is reported to be 70 kilometres and maximum altitude is greater than 24 kilometres. The minimum flight time is the time to arm the missile which is less than nine seconds and the maximum flight time is less than three and a half minutes.

RADAR

The AN//MPQ-53 phased array radar carries out search, target detection, target track, identification, missile tracking , missile guidance and electronic counter-countermeasures (ECCM) functions. The phased array radar is mounted on a trailer and is unattended in operation.

The radar is automatically controlled by a digital weapons control computer in the Engagement Control Station. The radar system has capacity to track up to 100 targets and provide the missile guidance data for up to nine missiles. The radar is connected to the Engagement Control System vehicle via a cable link.

M901 LAUNCHING STATION

The M901 Launching Station transports, points and launches the Patriot missile. Each launcher has four missiles. The launcher is remotely operated via a VHF data link or fibre optic data link from the Engagement Control Station which provides both the missile prelaunch data and the fire command signal. The Launching Station is equipped with an electrical power unit, a data link terminal module, a launcher electronics module and the four canisters with the missiles.

ENGAGEMENT CONTROL STATION

The AN/MSQ-104 Engagement Control Station is the only manned station in a Patriot Fire Unit and it provides the human interface for control of the automated functions. The Control Station communicates with the M901 Launching Stations, with other Patriot Fire Units (i.e. other Patriot batteries) and the higher command headquarters.

The Control Station is manned by three operators who have two operator consoles and a communications station. The communications station has three radio relay terminals. Between the two operator stations is the Patriot Fire Unit (or Patriot battery) status panel with a hard copy printer. The digital Weapon Control Computer is located next to the VHF Data Link Terminals.

TARGET ENGAGEMENT

In some cases the Patriot Fire Unit receives early warning of enemy missile launch, with direction and time of arrival data. The radar is capable of acquiring incoming missiles at ranges up to 100 kilometres. A target engagement can be carried out in manual, semi-automatic or automatic mode. When the decision has been made to engage the target, the Engagement Control Station selects the Launch Station or Stations to be used and pre-launch data is transmitted to the selected missile via VHF or fibre optic data link. The target position data is downloaded to the missile to aid the missile's target acquisition. After launch the Patriot missile is acquired by the phased array radar. The missile track command uplink and the TVM downlink between the Patriot missile and the radar allows the missile's flight to be monitored and provides the missile guidance commands from the weapon control computer in the Engagement Control System. As the missile approaches the target, the track-via-missile (TVM) guidance system on the missile is activated and the missile is steered toward the target. As the missile's closest approach to the missile is reached, a proximity fuse detonates the high explosive warhead.