Defense Primer: Electronic Warfare

The following is the Nov. 14, 2022, Congressional Research Service report Defense Primer: Electronic Warfare. From the report Electronic warfare (EW), as defined by the Department of Defense (DOD), are military activities that use electromagnetic energy to control the electromagnetic spectrum (“the spectrum”) and attack an enemy. The spectrum is a range of frequencies for […]

The following is the Nov. 14, 2022, Congressional Research Service report Defense Primer: Electronic Warfare.

From the report

Electronic warfare (EW), as defined by the Department of Defense (DOD), are military activities that use electromagnetic energy to control the electromagnetic spectrum (“the spectrum”) and attack an enemy. The spectrum is a range of frequencies for electromagnetic energy. EW supports command and control (C2) by allowing military commanders’ access to the spectrum to communicate with forces, while preventing potential adversaries from accessing the spectrum to develop an operational picture and communicate with their forces. Some have argued that EW is a component of anti-access/area denial (A2/AD) campaigns.

Role of EW in Military Operations

Since the introduction of two-way radios, militaries have become dependent on the spectrum. This reliance has expanded over the past century to include nearly every weapon system. Applications include

  • radio frequencies to communicate with friendly forces;
  • microwaves for tactical data-links, radars, and satellite communications;
  • infrared for intelligence and to target enemies; and
  • lasers across the entire spectrum to communicate, transmit data, and potentially destroy a target.

Modern militaries rely on communications equipment that uses broad portions of the spectrum to conduct military operations. This allows forces to talk, transmit data, provide navigation and timing information, and to command and control forces all over the world. They also rely on this to know where adversaries are, what adversaries are doing, where friendly forces are, and what effects weapons achieve. As a result, modern militaries attempt to dominate the spectrum through electronic warfare. From the perspective of military operations, there are three broad divisions of electronic warfare

  • Electronic protection involves actions to protect access to the spectrum for friendly military assets.
  • Electronic attack uses electromagnetic energy to degrade or deny an enemy’s use of the spectrum.
  • EW support identifies and catalogues emissions of friendly or enemy forces to either protect U.S. forces or develop a plan to deny an enemy’s access to the spectrum.

These subsets of EW often mutually support each other in operations. EW support uses equipment to assess both friendly and adversary electronic emissions. This information can then be used to develop a protection plan to maintain access to the spectrum or an attack plan to deny adversaries vital access. Radar jamming (electronic attack) can serve a protection function for friendly forces to penetrate defended airspace, and it prevents an adversary from having a complete operating picture.

In general, the more advanced a military adversary, the greater role EW plays in combat.

Types of EW Capabilities

As electronic warfare affects all military domains—land, air, sea, space, and cyberspace—each of the military services has its own EW capabilities and programs. EW capabilities are traditionally categorized into two distinct categories: terrestrial and airborne. Because each kind of EW has its respective advantages and disadvantages, multiple capabilities may be required to provide a desired effect. For example, airborne EW is used to intercept, decrypt, and disrupt communications, radars, and other C2 systems over a large area. However, these capabilities may be limited by aircraft endurance and are therefore unable to provide certain EW effects. Examples of airborne EW programs include the E-2 Hawkeye, the EA-18G Growler, the RC-135 Rivet Joint, and the EC-130H Compass Call.

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