Updated May 24, 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 emerging operational concepts it
power available; these capabilities are also limited due to
intends to use to counter adversaries, including the Naval
variance in the terrain in which they operate. Ground EW
Integrated Fire Control-Counter Air (NIFC-CA) concept,
capabilities were traditionally used to intercept and to jam
which is designed to help the carrier air wing to better
radios and artillery radars. More recent uses include
counter adversaries in denied and degraded environments.
jamming improvised explosive devices (IEDs) in Iraq and
The Chief of Naval Operations, in his April 2018 posture
Afghanistan. Representative ground EW capabilities
testimony before the Armed Services Committees,
include the vehicle-mounted Counter Remote Controlled
discussed the need to invest more in EW capabilities for the
IEDs (CREW) Duke system and the Thor III dismounted
surface fleet. The EA-18G Growler aircraft, which is the
CREW system.
backbone of the Navy’s EW programs, continues to receive
funding to modernize its capabilities, including funding for
Modern-day military operations also rely on satellite-based
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. As a result, the service is
upgrading EC-130H Compass Call EW payloads in the
DOD EW Policy
near-term. The Air Force has requested funding for two EC-
The National Defense Strategy, released in 2018,
37s (using a Gulfstream platform), with an intent to
emphasized the return of great-power competition,
purchase 10 over the next 10 years.
reflecting China’s and Russia’s ongoing efforts to
modernize their forces to counter U.S. military advantages.
Organization of EW
In addition, the congressionally mandated National Defense
DOD has several organizations responsible for developing
Strategy Commission, which independently evaluated DOD
and maintaining EW capabilities. The EW Executive
strategy, stated that the United States is losing its
Committee (EW EXCOM)—led by the Deputy Secretary of
advantages in electronic warfare, hindering the nation’s
Defense—is tasked with synchronizing and integrating EW
ability to conduct military operations against capable
across DOD components by sharing tactics, techniques,
adversaries. The commission recommended increasing EW
procedures, intelligence, and technologies. The EW
investments and developing new concepts to regain U.S.
EXCOM is responsible for establishing DOD EW policy.
military advantage. Each service has incorporated EW
capabilities into platforms and combat systems and is
The FY2019 National Defense Authorization Act (NDAA)
currently working to modernize its existing capabilities.
mandated the creation of an EW Cross Functional Team to
develop an electronic warfare strategy, including an
Army
assessment of vulnerabilities and capability gaps, leading to
The Secretary of the Army and the Chief of Staff of the
an acquisition plan. The most recent DOD EW strategy was
Army testified this year that developing new EW
released in 2017. The FY2017 NDAA directed DOD to
capabilities and programs was the Army’s fourth most
develop and release a new strategy to report to Congress.
important modernization. The Army plans to invest in both
The FY2018 NDAA also required DOD to contract an
airborne and ground-based EW programs aimed at making
independent assessment of its EW capabilities, with a report
the service more competitive with peer adversaries. This
due October 1, 2019.
investment includes standing up a new organization
devoted to the EW mission, procuring long-endurance,
CRS Products
unmanned airborne EW systems, and unit-level training.
CRS Report R44572, U.S. Airborne Electronic Attack Programs:
Marine Corps
Background and Issues for Congress, by John R. Hoehn
Similarly, the Commandant of the Marine Corps has
CRS In Focus IF11155, Defense Primer: Military Use of the
testified in posture statements since 2017 about the need for
Electromagnetic Spectrum, by John R. Hoehn
modern EW capabilities for expeditionary maritime
operations. The Marine Corps continues to sustain and
Other Resources
modernize its radio battalions—units specifically designed
around signatures intelligence and electronic warfare—
DOD. Joint Pub. 3-13.1, Electronic Warfare, Feb. 8, 2012.
alongside additional aviation programs. Such programs
DOD. DOD Directive 3222.4 Electronic Warfare Policy,
include the F-35B Lightning II aircraft. Another important
March 26, 2014, with Change 2, Effective August 31, 20118.
initiative outlined in the most recent Marine Corps’ concept
is signature management, which attempts 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
IF11118
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