Defense Primer: Electronic Warfare
Updated November 14, 2022
Defense Primer: Electronic Warfare
Electronic warfare (EW), as defined by the Department of
Electronic protection involves actions to protect access
Defense (DOD), are military activities that use
to the spectrum for friendly military assets.
electromagnetic energy to control the electromagnetic
Electronic attack uses electromagnetic energy to
spectrum (“the spectrum”) and attack an enemy. The
degrade or deny an enemy’s use of the spectrum.
spectrum is a range of frequencies for electromagnetic
EW support identifies and catalogues emissions of
energy. EW supports command and control (C2) by
friendly or enemy forces to either protect U.S. forces or
allowing military commanders’ access to the spectrum to
develop a plan to deny an enemy’s access to the
communicate with forces, while preventing potential
spectrum.
adversaries from accessing the spectrum to develop an
These subsets of EW often mutually support each other in
operational picture and communicate with their forces.
operations. EW support uses equipment to assess both
Some have argued that EW is a component of anti-
friendly and adversary electronic emissions. This
access/area denial (A2/AD) campaigns.
information can then be used to develop a protection plan to
Role of EW in Military Operations
maintain access to the spectrum or an attack plan to deny
adversaries vital access. Radar jamming (electronic attack)
Since the introduction of two-way radios, militaries have
can serve a protection function for friendly forces to
become dependent on the spectrum. This reliance has
penetrate defended airspace, and it prevents an adversary
expanded over the past century to include nearly every
from having a complete operating picture.
weapon system. Applications include
radio frequencies to communicate with friendly forces;
In general, the more advanced a military adversary, the
microwaves for tactical data-links, radars, and satellite
greater role EW plays in combat.
communications;
Types of EW Capabilities
infrared for intelligence and to target enemies; and
lasers across the entire spectrum to communicate,
As electronic warfare affects all military domains—land,
transmit data, and potentially destroy a target.
air, sea, space, and cyberspace—each of the military
services has its own EW capabilities and programs. EW
Modern militaries rely on communications equipment that
capabilities are traditionally categorized into two distinct
uses broad portions of the spectrum to conduct military
categories: terrestrial and airborne. Because each kind of
operations. This allows forces to talk, transmit data, provide
EW has its respective advantages and disadvantages,
navigation and timing information, and to command and
multiple capabilities may be required to provide a desired
control forces all over the world. They also rely on this to
effect. For example, airborne EW is used to intercept,
know where adversaries are, what adversaries are doing,
decrypt, and disrupt communications, radars, and other C2
where friendly forces are, and what effects weapons
systems over a large area. However, these capabilities may
achieve. As a result, modern militaries attempt to dominate
be limited by aircraft endurance and are therefore unable to
the spectrum through electronic warfare. From the
provide certain EW effects. Examples of airborne EW
perspective of military operations, there are three broad
programs include the E-2 Hawkeye, the EA-18G Growler,
divisions of electronic warfare
the RC-135 Rivet Joint, and the EC-130H Compass Call.
Figure 1. How EW Affects the Spectrum
Source: https://cyberdefense.com/spectrum-warfare.
https://crsreports.congress.gov
Defense Primer: Electronic Warfare
Terrestrial EW sensors and jammers—which can be located
Navy
on land or on ships at sea—are limited by the amount of
The Navy has several new operational concepts it intends to
power available; these capabilities are also limited due to
use to counter adversaries, including the Naval Integrated
variance in the terrain in which they operate. Ground EW
Fire Control-Counter Air (NIFC-CA) concept, designed to
capabilities traditionally focused on intercepting and
help the carrier air wing to better counter adversaries in
jamming radios and artillery radars. Recent uses include
denied or degraded environments. The Chief of Naval
jamming improvised explosive devices (IEDs).
Operations, in his 2018 posture testimony before the Armed
Representative ground EW capabilities include the vehicle-
Services Committees discussed investing more in EW
mounted Counter Remote Controlled IEDs (CREW) Duke
capabilities for the surface fleet. The EA-18G Growler
system and the Thor III dismounted CREW system.
aircraft, which is the backbone of the Navy’s EW programs,
continues to receive funding to modernize its capabilities,
Modern-day military operations also rely on satellite-based
including funding for the Next Generation Jammer.
EW capabilities, including for broad area surveillance and
early-warning, communications, command and control.
Air Force
Specific programs include
The Air Force’s concepts of air superiority and
multidomain command and control require assured access
Space Based Infrared System (SBIRS) constellation;
to the spectrum. The Secretary of the Air Force and the Air
electronic intelligence by satellite (ELISA) electronic
Force Chief of Staff stated during their 2018 posture
intelligence satellites; and
hearing the need to maintain EW capabilities to support the
space-based radar systems.
Air Force’s future development. Thus, the service is
DOD EW Policy
upgrading EC-130H Compass Call EW payloads and
procuring EC-37s, with an intent of purchasing new 10
The National Defense Strategy, released in 2022, continued
aircraft. Six aircraft are already on contract.
the emphasis on return of great-power competition,
reflecting China’s and Russia’s ongoing efforts to
Organization of EW
modernize their forces to counter U.S. military advantages.
DOD has several organizations responsible for developing
In addition, the congressionally mandated National Defense
and maintaining EW capabilities. The EW Executive
Strategy Commission, which independently evaluated DOD
Committee—led by the Deputy Secretary of Defense—is
strategy, stated that the United States is losing its
tasked with synchronizing and integrating EW across DOD
advantages in electronic warfare, hindering the nation’s
components by sharing tactics, techniques, procedures, and
ability to conduct military operations against capable
technologies. The EW EXCOM also establishes DOD EW
adversaries. The commission recommended increasing EW
policy. The FY2019 National Defense Authorization Act
investments and developing new concepts to regain U.S.
directed the creation of an Electromagnetic Spectrum
military advantage. Each service has incorporated EW
Operations Cross Functional Team to develop an electronic
capabilities into platforms and combat systems and is
warfare strategy, including assessments of vulnerabilities
currently working to modernize its existing capabilities.
and capability gaps, leading to an acquisition plan. The
Army
Electromagnetic Spectrum Superiority Strategy was
published on October 29, 2020.
The Secretary of the Army and the Chief of Staff of the
Army testified this year that developing new EW
CRS Products
capabilities and programs was the Army’s fourth most
important modernization. The Army plans to invest in both
CRS Report R44572, U.S. Airborne Electronic Attack Programs:
airborne and ground-based EW programs aimed at making
Background and Issues for Congress, by John R. Hoehn
the service more competitive with peer adversaries. This
CRS Report R45919, Ground Electronic Warfare: Background
investment includes standing up a new organization
and Issues for Congress, by John R. Hoehn
devoted to the EW mission, procuring long-endurance,
CRS In Focus IF11155, Defense Primer: Military Use of the
unmanned airborne EW systems, and unit-level training.
Electromagnetic Spectrum, by John R. Hoehn
Marine Corps
CRS In Focus IF11882, Defense Primer: Directed-Energy
The Commandant of the Marine Corps has testified since
Weapons, by Kelley M. Sayler and John R. Hoehn
2017 about requiring modern EW capabilities for
expeditionary maritime operations. The Marine Corps
Other Resources
continues to sustain and modernize its radio battalions—
DOD. Electromagnetic Spectrum Superiority Strategy,
units specifically designed around signatures intelligence
October 29, 2020
and electronic warfare—alongside additional aviation
Joint Pub. 3-85, Joint Electronic Magnetic Spectrum
programs, including the F-35B Lightning II aircraft.
Operations, May 22, 2020.
Another initiative outlined in the most recent Marine Corps’
concept is signature management, which aims to limit
emissions to prevent adversaries’ access to precise locations
of about U.S. forces.
John R. Hoehn, Analyst in Military Capabilities and
Programs
IF11118
https://crsreports.congress.gov
Defense Primer: Electronic Warfare
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11118 · VERSION 12 · UPDATED