The Raytheon-developed Patriot system dates back 20 years. Since initial deployment in 1980, around 9,000 missiles and 170 fire units have been produced for the US military and eight other nations. Around $2 billion has been invested to improve PAC-2 effectiveness in the wake of its 1991 combat debut. With the weapon due to remain in US Army service until 2028, further improvements are planned.

Raytheon originally designed Patriot to provide air defence for relatively confined areas of operations and so, when it was called on to provide extended coverage of large urban areas of Israel in 1991, the missile was less than successful in countering Iraqi Scud attacks. As a result, the PAC-2 system was modified to remotely position launchers forward of the control station, while there was a doubling of the radar's sensitivity to enable it to better distinguish warheads from missile debris.

The mid-1990s saw the addition of an enhanced weapon control computer, doppler processor and the introduction of the guidance enhanced missile (GEM), followed in 1997 by further improvements to the radar and communications. The GEM+ missile introduced in 2000 is designed to improve PAC-2 effectiveness against TBMs through upgrades to the missile's sensor and digital fuze, which can be re-programmed in flight.

Compared to the PAC-2 system used during the Gulf War, the combination of PAC-3, GEM+ and remote launchers now gives a Patriot battery seven times more coverage. There has also been a twofold increase in detection range against cruise missile threats, says Tim Carey, Raytheon vice-president Patriot business.

Additional improvements will come with the introduction of a lighter and more reliable communications antenna mast-mounted on a Humvee vehicle, which was demonstrated to the army in 2001 and is now under contract. Another demonstration planned for this year will be an improved mobile command and control system employing elements of the THAAD battle management system. In the longer term Raytheon wants to introduce a smaller, 360¼ radar with improved processors, mounted on a truck.

Source: Flight International