Since 1975, IR missiles have become the number one threat to military aircraft – fighters, helicopters and wide-body fixed wing aircraft

It is a well-known fact that 90 percent of all aircraft losses in the last 15 years, are the result of Man Portable Air Defense System (MANPADS) missiles. During the 1991 Persian Gulf War, 12 of the 29 American aircraft lost during combat operation are believed to have been shot down by Iraqi SA-16 Iglas. The Russians have suffered even more from MANPADS in their battles in Afghanistan with losses of more than 250 aircraft to Stinger missiles as well as, and more recently, in Chechnya .

The following table presents some published data for the period of 1975 to 1992:

Event	Shot Down By	Shot Down	% of Total Shot Down
1975-1985	IR Missiles (A/A and S/A) RF Missiles Guns	149 2 10	93 1 6
Afghanistan Wa	IR Missiles (S/A)	> 1000	68
Desert Storm	IR Missiles (A/A and S/A)	38	85

In order to protect a platform against MANPADS and IR seeking missiles, the aircraft should be equipped with a protection suite that includes a Missile Warning System and countermeasure equipment. Countermeasure types can be flares or Directional IR Counter-Measures (DIRCM). The use of flares is insufficient and limited for several reasons:

•  Modern threats are immune to flares, thus flares have no effect on them.
•  Flares have no effect on any threat when fired from short range.
•  The platform can carry a limited quantity of flares, thus shortening the mission.
•  Developing a flare against a new threat takes a very long time.
•  Flares have no effect on anti-tank missiles.
•  The LCC of flares is high compared to DIRCM.
•  There is no protection while on the ground.

1. Detection - The MWS initiates the process upon detection of the threat and the turret is swiftly directed towards it.
2. Hand Off - The turret is then slaved to the MWS, which immediately tracks the missile trajectory.
3. Defeat - The system’s processing unit selects the optimal jamming technique according to available information in order to defeat the threat.

Fig. 1 AERO-GEM Block Diagram

Israel , May 2, 2001 . To counter the threat of anti-aircraft missiles, RAFAEL, Israel 's Armament Development Authority, has developed a passive and autonomous warning system - the Guitar-350 for fighter aircraft, helicopters and transport aircraft.

RAFAEL's Guitar is a totally passive warning system that works in the electro-optical spectral band and detects ground-to-air and air-to-air missiles, by sensing the electro-optical emissions of the missile's motor. When it detects the missile, the Guitar system provides an alarm and activates the Infra-Red Countermeasures (IRCM or DIRCM) of the aircraft.

The development of the Guitar system into a reliable Missile Warning System (MWS) is the result of RAFAEL's high scientific and technological level, combined with battle experience. This combination provides a unique design which incorporates a high resolution MWS with a sophisticated detection algorithm. This enables the Guitar system to significantly reduce false alarm rate and to increase the detection range of threatening missiles. The advanced electro-optical imaging staring sensor developed for the Guitar system is capable of identifying the launch of a missile, of tracking its trajectory and of transferring data on “Time To Impact” (TTI).

The system uses 120 0 sensors for full spherical coverage. The system's Processing Unit includes an Internal Inertial Angular Unit to compensate aircraft maneuvers.

Using unique larger collecting optics, Guitar is more sensitive than any existing MWS of the same kind, thus providing longer detection ranges.

On detection of a missile, Guitar provides the pilot with a visual and audio alarm and further information about the missile threat. Furthermore, Guitar can automatically activate the aircraft's IRCM/Flare system. Thus, the Guitar system provides optimal protection to helicopters, fighters and transport aircraft.

The Guitar system has been successfully tested and proven against more than 100 missiles of all kinds, in live exercises, including air-to-air, anti-armor and surface-to-air missiles. Each and every missile was detected on launch, and tracked during flight with high angular accuracy. False targets (flares, explosives, etc.) were rejected by the system's sophisticated algorithms.

Technical properties of the Guitar system include:

• Wide spatial cover of 360 0 in azimuth and 120 0 in elevation, with 4 sensors, covering all attack angles for helicopters protection.
• Full spherical coverage with 6 sensors, as required for fighter aircraft.
• Early warning time - 4 to 6 seconds before impact.
• Weight - less than 15 Kg.
• Power requirements - less than 200W.

An important property of the Guitar system is that it is totally passive, it emits no electro-magnetic or electro-optical signals, which might be intercepted by hostile receivers. The system's algorithm provides high discrimination rate of background interference, which drastically reduces false alarms. It should be also pointed out that simple installation requirements, light weight and low power consumption make it possible to install and integrate the Guitar system easily on all existing aircraft.

The Guitar system is a product of RAFAEL, Israel 's Armament Development Authority, which has been developing state-of-the-art protection systems, as well as many combat systems for over 50 years. RAFAEL's products have been tested and proven on the battlefield by the Israeli Armed Forces and by other major armies of the world.