The Decoy Launching System (DLS) Mk 53 (NULKA) is a rapid response Active Expendable Decoy (AED) System capable of providing highly effective defense for ships of cruiser size and below against modern radar homing anti-ship missiles. Nulka is being developed in cooperation with Australia (in the Australian Aboriginal dialect, "Nulka" means "be quick!"). It is intended to counter a wide spectrum of present and future radar-guided anti-ship missiles (ASMs) assessed to have passive decoy rejection and active angular deflection electronic countermeasures rejection capabilities. It is designed to over-come the inherent shortfalls of chaff, which are wind dependence, lack of placement flexibility, relatively slow reaction time, and susceptibility to Doppler discrimination.
The system can either be integrated with the Combat System or used with the stand-alone AED Fire Control System. The DLS MK 53 Mod 4 is a modified DLS MK 36 Mod 12 by the addition of two NULKA launching tubes to each of the four MK 137 Mod 2 launchers and a Decoy Launch Processor.
The Nulka decoy employs a broad-band radio frequency repeater mounted atop a hovering rocket platform. After launch, the Nulka decoy radiates a large, ship-like radar cross section while flying a trajectory that seduces and decoys incoming ASMs away from their intended targets. The NULKA decoy is an active offboard decoy which utilizes a broad band radio frequency repeater mounted atop a hovering rocket. The decoy is an autonomous flight vehicle, capable of operating over a wide range of environments and of positioning the payload with a high level of accuracy. The decoy employs the hovering rocket principle and uses a solid state microprocessor autopilot and thrust vector control. The decoy is designed to counter a wide variety of present and future radar Anti-Ship Missile (ASM) guided threats by radiating a large radar cross section signal while flying a ship-like trajectory thus enabling one decoy to counter multiple threats. The flight trajectory is determined by a digital Flight Control Unit mounted immediately above the rocket motor. The combination of thrust and flight control enables successful decoy launches to be accomplished even in severe sea state and high wind conditions. The Processor Power Supply controls the decoy launching by igniting the decoys thermal batteries, monitoring the decoy self check process, downloading the decoy flight program and then igniting the rocket motor. Once launched the decoy operates autonomously and follows the stored flight demands, moving away from the ship at a pre-programmed height and speed and thus presenting an alternative and more attractive target to incoming missiles. Australia is developing the hovering rocket, launcher, and launcher interface unit. The United States is developing the electronic payload and fire control system, which is presently being integrated into the SSDS. Recent upgrades to Nulka include improved payload to reduce cost and modifications to the fire control system to reduce the system’s overall weight. The existing Mk 36 Decoy Launching System is being modified to support Nulka launches. After the Nulka equipment is installed, the system is redesignated as a Mk 53 DLS. Nulka can be used as part of a multi-layer defense system, or it can be used for stand-alone ship protection. The Nulka Decoy System has been successfully tested as a part of the Navy's Ship Self Defense System (SSDS). Introduction priority will be given to ship classes that are presently without an active electronic warfare suite to provide an increased ASM defense capability. Due to the ever changing complexity of Anti-Ship Cruise Missiles, Nulka will be continually upgraded in order to provide protection to the Fleet. Changes will include technology advancement as well as tactical and technical changes to counter the threat.
