Updated December 30, 2019
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
maintain access to the spectrum or an attack plan to deny
Role of EW in Military Operations
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
In general, the more advanced a military adversary, the
radio frequencies to communicate with friendly forces;
greater role EW plays in combat.
microwaves for tactical data-links, radars, and satellite
communications;
Types of EW Capabilities
infrared for intelligence and to target enemies; and
As electronic warfare affects all military domains—land,
lasers across the entire spectrum to communicate,
air, sea, space, and cyberspace—each of the military
transmit data, and potentially destroy a target.
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.
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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 were traditionally used to intercept and to jam
help the carrier air wing to better counter adversaries in
radios and artillery radars. More recent uses include
denied or degraded environments. The Chief of Naval
jamming improvised explosive devices (IEDs) in Iraq and
Operations, in his 2018 posture testimony before the Armed
Afghanistan. Representative ground EW capabilities
Services Committees discussed needing to invest more in
include the vehicle-mounted Counter Remote Controlled
EW capabilities for the surface fleet. The EA-18G Growler
IEDs (CREW) Duke system and the Thor III dismounted
aircraft, which is the backbone of the Navy’s EW programs,
CREW system.
continues to receive funding to modernize its capabilities,
including funding for the Next Generation Jammer.
Modern-day military operations also rely on satellite-based
EW capabilities, including for broad area surveillance and
Air Force
early-warning, communications, command and control.
The Air Force’s concepts of air superiority and
Specific programs include
multidomain command and control require assured access
to the spectrum. The Secretary of the Air Force and the Air
Space Based Infrared System (SBIRS) constellation;
Force Chief of Staff stated during their 2018 posture
electronic intelligence by satellite (ELISA) electronic
hearing the need to maintain EW capabilities to support the
intelligence satellites; and
Air Force’s future development. As a result, the service is
space-based radar systems.
upgrading EC-130H Compass Call EW payloads in the
near-term. The Air Force requested funding for two EC-37s
DOD EW Policy
(using a Gulfstream platform), with an intent to purchase 10
The National Defense Strategy, released in 2018,
over the next 10 years.
emphasized the 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,
ability to conduct military operations against capable
intelligence, and technologies. The EW EXCOM is
adversaries. The commission recommended increasing EW
responsible for establishing DOD EW policy. The FY2019
investments and developing new concepts to regain U.S.
National Defense Authorization Act (NDAA) mandated the
military advantage. Each service has incorporated EW
creation of an EW Cross Functional Team to develop an
capabilities into platforms and combat systems and is
electronic warfare strategy, including assessments of
currently working to modernize its existing capabilities.
vulnerabilities and capability gaps, leading to an acquisition
plan. The most recent DOD EW strategy was released in
Army
2017. The FY2017 NDAA directed DOD to develop and
The Secretary of the Army and the Chief of Staff of the
release a new strategy to Congress. The FY2018 NDAA
Army testified this year that developing new EW
required DOD to contract an independent assessment of
capabilities and programs was the Army’s fourth most
EW capabilities, with a report due October 1, 2019.
important modernization. The Army plans to invest in both
airborne and ground-based EW programs aimed at making
CRS Products
the service more competitive with peer adversaries. This
investment includes standing up a new organization
CRS Report R44572, U.S. Airborne Electronic Attack Programs:
devoted to the EW mission, procuring long-endurance,
Background and Issues for Congress, by John R. Hoehn
unmanned airborne EW systems, and unit-level training.
CRS Report R45919, Ground Electronic Warfare: Background
and Issues for Congress, by John R. Hoehn
Marine Corps
CRS In Focus IF11155, Defense Primer: Military Use of the
The Commandant of the Marine Corps has testified in
Electromagnetic Spectrum, by John R. Hoehn
posture statements since 2017 about the need for modern
EW capabilities for expeditionary maritime operations. The
Marine Corps continues to sustain and modernize its radio
Other Resources
battalions—units specifically designed around signatures
DOD. Joint Pub. 3-13.1, Electronic Warfare, February 8, 2012.
intelligence and electronic warfare—alongside additional
DOD. DOD Directive 3222.4 Electronic Warfare Policy,
aviation programs. Such programs include the F-35B
March 26, 2014, with Change 2, Effective August 31, 2018.
Lightning II aircraft. Another initiative outlined in the most
recent Marine Corps’ concept is signature management,
which aims to limit emissions so that adversaries have less
precise information about U.S. operating locations.
John R. Hoehn, Analyst in Military Capabilities and
Programs
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Defense Primer: Electronic Warfare
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