No matter how sophisticated the countermeasures, there always remain a chance that an offensive weapon would find its target. It is to enhance survivability against such a possibility, that towed decoys have now being integrated into combat aircraft’s defensive suites.

Threats emanatin g from employment of electromagnetic spectrum for offensive purposes have been significant features of modern warfare since the invention of radar. With advancement of technology, these threats which include surface-to-air and air-to-air radar guided missiles have grown both in quantum as well as sophistication exponentially. Traditionally, combat aircraft have relied on a variety of onboard jammers for self-protection. These jammers emit electronic signals to impede or deny the threat radar’s ability to precisely locate the aircraft, thus negating the weapon’s effectiveness. In response to development of ever more effective radars, increasingly versatile jammers have become an essential part of combat aircraft’s defensive suites. However, no matter how sophisticated the countermeasures, there always remain a chance that an offensive weapon would find its target. It is to enhance survivability against such a possibility, that towed decoys are now being integrated into combat aircraft’s defensive suites.

Two outstanding examples of this approach are the American AN/ALE-50 and integrated defensive electronic countermeasures (IDECM) system which includes AN/ALE-55 fibreoptic towed decoy (FOTD) as one of its major components.

AN/ALE-50 Towed Decoy System jointly developed by a US Air Force/Navy/Raytheon integrated product team is an anti-missile decoy system effective against active and semi-active radar guided airto-air and surface-to-air missiles. First deployed in 1996 on a USAF F-16, this anti-missile decoy is currently operational on the F-16, F/A-18E/F, and B-1B aircraft.

The system consists of:

• A launch controller, containing the decoy’s power supply, and control/monitoring electronics
• A launcher which holds the decoy magazine and can be customised to fit any candidate aircraft
• Towed decoys packaged in a sealed canister, which also contains the payout reel

AN/ALE-50 towed decoy component generates and emits its own signals that are intended to lure an incoming radar-guided weapon away from the aircraft by presenting a more attractive target. This stand-alone system requires no threat specific software. It communicates its health and status to its host aircraft over a standard data bus.

AN/ALE-50 has validated an effective concept of survivability. To enhance its usefulness further, Raytheon was considering several expanded applications. On the anvil was a higher power fibre-optic towed version for protection of larger aircraft. It was also working closely with the USAF and US Navy to develop an infrared towed decoy so that the AN/ALE-50 could provide equally effective protection against both RF as well as infrared threats.

F-16 used a platform-specific integrated launcher/launch controller mounted in a wing pylon for the decoy’s integration with the aircraft. For all future installations, a standard multi-platform launch controller (MPLC) has been developed. With platform specific launchers, MPLC will make AN/ALE-50 adaptable to any tactical or combat support aircraft.

Slated for deployment on the F/A-18E/F, the B-1B and the F-15 aircraft is an integrated defensive electronic countermeasures system (IDECM). Conceptually it makes a departure from the conventional approach and incorporates onboard receivers and off-board countermeasures.

IDECM system has three major components:

• ALR-67(V)3 radar warning receiver.
• AN/ALQ-214 radio-frequency countermeasures system (RFCM).
• AN/ALE-5 fibre-optic towed decoy system which combines an on-board electronic frequency converter (EFC) and fibre-optic towed decoy. The EFC converts radio frequencies to light, and sends the data through a fibre-optic line to the decoy.