U.S. Carrier Group Tactics - Detection and Electronic Warfare

Detection and Electronic Warfare

In modern naval combat a deadly strike can be launched from 600 nautical miles (1,100 km) away. This is a huge area to scout. The double-edged answer to this is electronic warfare.

Electronic warfare (EW) consists of three elements — Electronic Support Measures (ESM), Electronic Counter-Measures (ECM) and Electronic Counter-Counter-Measures (ECCM).

ESM is the passive detection of enemy electromagnetic (EM) emissions. The radiated energy of an emitter (e.g. radar) can be detected far beyond the range at which it returns a usable result to its user. Modern ESM can identify the actual class of the emitter, which helps identify the unit on which it is used. Passive cross-fixing between a number of units can locate a source to a reasonably small area and give some hint to direction and speed. ESM fixes are placed in three classes: Detected, Tracking and Targeted, depending on the accuracy of the fix and whether a unit's course and speed has been derived. Of course for ESM to work the enemy must 'co-operate' by using their emitters.

The fact that a missile launched on a passive fix from over-the-horizon is usually deadly, creates a central problem for a naval force -- when, and even if, units should radiate, and if not how to detect the enemy? This is detectability vs. survivability. The need to obtain a targeting solution has to be balanced against the enemy's ability to do the same. Although once a commander feels that his fleet's position is known to the enemy a move to active emissions may be vital to prevent destruction, or else the only warning of incoming missiles will be when they turn on their terminal guidance systems.

Making this decision is called EMCON (EMissions CONtrol). There are three states, A, B and C. A is no emissions, B is limited emissions (no unique emissions), and C is unrestricted. EMCON is not a blanket condition across the fleet. The surface units can be at A while a sufficiently distant AEW aircraft can be at C.

ECM is both offensive and defensive, covering all methods used to deny targeting information to an enemy. Offensive ECM is usually jamming. This prevents the accurate detection and identification of incoming strikes until the jamming unit is destroyed. Chaff is also used to confuse AAW operations by creating radar decoys. Defensive ECM also uses chaff as well as soids, blip enhancement and jamming of missile terminal homers.