TheAN/ALQ-144,AN/ALQ-147, andAN/ALQ-157 are US infraredanti-aircraft missilecountermeasure devices (IRCM). They were developed bySanders Associates in the 1970s to counter the threat ofinfrared guidedsurface-to-air missiles like the9K32 Strela-2. While decoy flares were effective at jamming first generation infra-redguided missiles, each flare was only effective for a short period. If an aircraft needed to loiter over a high risk area or was flying slowly (as helicopters do), it would require a large number of flares to decoy any missile fired at it. The IRCM provided constant protection against infra-red guided missiles.
The ALQ-144 and ALQ-147 were first delivered to theUS military in 1981. Currently there are over 3,500 in use with the US military, and a total of 6,000 in use by nineteen countries globally. Seven hundred ALQ-157 systems are currently in service.[citation needed]
In accordance with theJoint Electronics Type Designation System (JETDS), the "AN/ALQ-144", "-147" and "-157" designations represent the 144th, 147th and 157th designs of an Army-Navy airborne electronic device for specialcountermeasures equipment. The JETDS system also now is used to name allDepartment of Defense electronic systems.
Both systems consist of a heatedsilicon carbide block or cesium arc-lamp[1] that radiates a large amount of infra-red energy. It is surrounded by a large cylindrical mechanical shutter that modulates the infra-red output, producing a pulsing pattern. Early infrared guided missiles used a rotatingreticle. When a target was not on the sensor's centerline, it would produce a pulse as the reticle swept over the target. When the target was on the sensor's centerline, the sensor would produce a constant signal. This constant signal was required by the early missiles to produce a "lock on" that would allow a launch.
The ALQ-144 and 147 IRCM produced a pattern of pulses that was approximately synchronized with the rotation rate of these reticles. Before launch this would prevent the missile actually locking onto the target, preventing the operator from firing the missile. After launch this would cause the missile to think that the target was off to one side and cause the missile to steer away from the aircraft carrying the IRCM.
The introduction of rosette and "staring" scanning techniques in second generation missiles reduced the effectiveness of the ALQ-144 and 147; later upgrades restored the effectiveness of the jammers.
The ALQ-144A was rushed into US service in time for the1991 Gulf War, as Iraq had stocks of9K34 Strela-3 and9K38 missiles, against which the ALQ-144 was only partially effective. By the time the war started, two-thirds of theAH-64 Apaches in the persian Gulf had been upgraded to ALQ-144A standard. The only AH-64 Apache lost to an infra-red guided missile was hit by a9K34 Strela-3 missile; the helicopter in question was one of the few that had not been upgraded.[2]
The ALQ-144's distinctive appearance has earned it the nicknames "disco light", "disco ball", "mirror-ball" or "R2-D2".
Produced byLoral, the system consists of two emitters, each one covering one side of a large aircraft. The system is microprocessor controlled and has five pre-set jamming patterns.
| Designation | Entered service | Output | Weight | Platforms |
|---|---|---|---|---|
| ALQ-144 | 1980 | 1.7 kW | 28 lb (12.5 kg) | AH-1J SeaCobra,AH-1S Cobra,AH-1T Improved SeaCobra,AH-1W SuperCobra,AH-64 Apache,EH-1H Iroquois,EH-60A Black Hawk,OV-10D Bronco,UH-1 Iroquois,UH-60 Black Hawk[3] |
| ALQ-147 | 1980 | ? | ? | |
| ALQ-157 | 1984 | 2 kW (later 4 kW) | 218 lb (99 kg) | C-130 Hercules,C-130J Super Hercules,CH-46E Sea Knight,CH-47 Chinook,CH-53 Sea Stallion,E-2C Hawkeye,P-3C Orion,SH-3 Sea King[4] |
| ActiveCountermeasures (Jamming) |
| ||||||||
|---|---|---|---|---|---|---|---|---|---|
| PassiveRadar Warning Receivers | |||||||||
| Missile Warning Systems | |||||||||
| Dedicated ECM /ESM aircraft |
| ||||||||
