Missiles Meet Their Nemesis

A joint major electronic countermeasures effort by the governments of the United Kingdom and the United States is designed to overcome the threat to aircraft posed by infrared surface-to-air missiles. The major electronic countermeasures project is to provide protection for both fixed- and rotary-wing aircraft with sensors that immediately identify a heat-seeking signal of an infrared-guided missile.

The directional infrared countermeasures, or DIRCM, system, known as Nemesis, transmits both missile threat location and direction to a turret assembly that is mounted on the aircraft, where a four-axis target designator system then acquires and tracks the missile through post burnout. DIRCM maintains a focused beam of infrared (IR) energy on the target throughout the full range of maneuvering, according to Larry O’Neil. He is London-based Northrop Grumman Electronic Sensors and Systems International’s director, infrared systems and technology.

DIRCM’s design also provides for subsequent incorporation of a laser as the technology sufficiently matures. A laser system was tested last August on a Blackhawk helicopter. The U.S. Blackhawk laser system is a 2-watt device that operates in Band 4 at 3 to 5 microns and in Band 1 at 1.5 microns, O’Neil says.

During the flight tests of the laser-based system at Fort Rucker, Alabama, the effectiveness of the prototype was confirmed. The laser, which was mounted on the Blackhawk helicopter, put its energy on target and defeated four different missile seeker types at various altitudes and ranges, O’Neil maintains.

The United Kingdom’s laser version will be tested in October and November on a Puma helicopter from the Defense Evaluation and Research Agency. This more powerful laser operates with 4 watts of power in Band 1 and Band 4, O’Neil continues.

This laser energy approach will allow the system to provide effective protection against future advanced threats without replacement of major components. DIRCM now operates with a krypton flash lamp until the lasers become available for installation. Currently in development, the laser-based system uses a compact mid-infrared device developed jointly with Fibertek Incorporated. The laser, known as Viper, is designed to produce multiple laser lines to jam all fielded IR-guided missiles, O’Neil offers.

The laser is packaged in a 2-inch-thick case that weighs less than 10 pounds and is designed for incorporation with both production configurations of the DIRCM system.

A new competitive program for use on large fixed-wing aircraft calls for system use with C-17s and C-130s. The laser system could be from BAE Systems, TRW, Lockheed Martin or Litton Laser. The first phase of the large-aircraft infrared countermeasures program is expected to be for 12 of the systems for the C-17 and eight for the C-130 aircraft, O’Neil discloses.

DIRCM, approximately a $490 million program through 2002, was initiated by the Ministry of Defence in the United Kingdom more than 10 years ago. The U.S. Special Operations Command began its participation in the program in 1993, O’Neil says. At the time of the program contract award in 1995, the United Kingdom planned to install the system on five types of helicopters and four types of fixed-wing aircraft. DIRCM is in production in the United Kingdom, and aircraft installations are underway. The British system will be in service this year.

The U.S. system will reach initial operational capability next year. The U.S. Special Operations Command let a contract for 60 of the systems for use on C-130 aircraft. The contract includes two transmitters per transport. The system also will be used to equip Apache helicopters, O’Neil confirms. DIRCM team members include BAE Systems, which provides the pointing and tracking subsystem, power supplies and the control unit as well as support for system effectiveness evaluation. The Boeing Company provides the advanced IR fine-tracking sensor system, he explains.

As team leader, Northrop Grumman and its subsidiary, Northrop Grumman Electronic Systems Integration International Incorporated, provides the system processor, power supply/modulator and the AN/AAR-54 missile warning system components. This company also provides systems engineering and integration, installation and effectiveness evaluation, O’Neil states.

The small-aircraft DIRCM system configuration successfully demonstrated its ability to defend against a variety of heat-seeking surface-to-air missiles during live-fire tests in 1998. Conducted at White Sands Missile Range, New Mexico, the tests confirmed that DIRCM could detect a missile in time to rapidly and accurately aim its turret’s beam of IR energy, O’Neil details. In 1999, flight tests and similar live-fire tests on the large system configuration proved equally successful. Last September, the Special Operations Command exercised its production option and procured DIRCM systems for its fleet of MC-130 Combat Talon aircraft and AC-130 Specter gunships.            —CAR