SubscribeThe use of small, reliable Unmanned Vehicles may solve the problem of effective yet affordable active electronic decoys protecting ships from their greatest threat, the subsonic or supersonic anti-ship cruise missile (ASM).
The weapon that poses the greatest threat to most modern Navies is the radar guided anti-ship missile or ASM. Because most ASM seekers rely on monopulse radar for terminal homing, they are not easily distracted by on-board countermeasures. The end-game is often defended by the use of concentrated ballistic counter-fire such as with the millimeter wave aimed Phalanx rapid fire machine gun. This enjoys limited success, however. Simultaneous multiple missile attack from different directions presents saturation conditions to onboard defenses.
Off-board active electronic decoys provide a much higher probability of successful defense because they offer a source of radiation providing counter-targeting or capture of the radar seeker of the ASM directing the missile away from the ship. They become particularly effective when placed at a location of optimum geometry relative to the ship and the missile and are activated at a time sufficiently in advance of missile launch or impact.
Because of their very high unit cost, expendable off-board active devices as the sole approach to decoying ASMs are proving less and less viable in modern naval warfare. Recent advances in unmanned vehicles (UVs), including Unmanned Aerial Vehicles (UAVs) and Unmanned Surface Vehicles (USVs), provide a more economical solution to this problem. Because of the high projected cost of expendables other than chaff and corner reflectors, and the consequent fiscal constraints on procurement for either war reserve or peacetime training, the prospect of a recoverable decoy system offers many advantages.
While it would not be appropriate for launch after detection of an inbound supersonic threat, the long time on-station characteristics of the UV decoy (in excess of three hours for most candidates) would permit deployment whenever a threat might be anticipated, and relief on station if the threat situation still exists for a longer period. As shown the UV decoy will dilute targeting of the capital ship and when in the terminal phase, will seduce the ASM away from the ship.
The capability for recovery would permit a far more cost effective ESM/ECM suite than would be otherwise possible for an expendable. Unmanned Aerial Vehicles (UAVs) or Unmanned Surface Vehicles (USVs) would permit launch and recovery from a limited deck space, because of their small size and would also allow storage in a relatively limited space.
A UAV or USV would also have the speed regime to either maintain station or transit to a new station (from stationary to several times faster than the ship’s maximum speed), and could be positioned to enhance Over-the-Horizon (OTH) detection and to minimize the effects of sea reflection multipath on ECM signal reception. A reasonable payload capacity (e.g., 50 kg) as shown would allow a higher ERP than could be achieved with an expendable, and also permits programmable or controllable modulations.
The control and data link capability provides reporting of intercepted signals along with their bearing. This will allow jamming control to be maintained on the controlling ship, providing a good estimate of the threat, allowing EW effectiveness assess- ment by comparison of signal levels and angle drift using on-board and off-board ESM assets. Finally, a mission flexible UV platform provides capabilities for multiple replaceable/modular payloads such as communications signals detection and direction finding (DF), radar detection and DF, and E-O surveillance for missions other than off-board countermeasures applications. UV decoys are effective against Air Launch, Sea Launch, or Coastal surveillance and ASM launching platforms.
