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Electronic countermeasure
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An electronic countermeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar, or other detection systems, like infrared (IR) or lasers. It may be used offensively and defensively to deny targeting information to an enemy. The system may make many separate targets appear to the enemy, or make the real target appear to disappear or move about randomly. It is used effectively to protect aircraft from guided missiles. Most air forces use ECM to protect their aircraft from attack. It has also been deployed by military ships and recently on some advanced tanks to fool laser/IR guided missiles. It is frequently coupled with stealth advances, so the ECM systems have an easier job. Offensive ECM often takes the form of jamming. Self-protecting (defensive) ECM includes blip enhancement and jamming missile terminal homers.
History
[edit]The first example of electronic countermeasures applied in combat occurred during the Russo-Japanese war. On July 13, 1904, Russian wireless telegraphy stations installed in the Port Arthur fortress and on board Russian light cruisers successfully interrupted wireless communication between Japanese battleships. The spark-gap transmitters in the Russian stations generated senseless noise while the Japanese were making attempts to coordinate their efforts in the bombing of a Russian naval base. During World War I, Germany and the United Kingdom interfered with enemy communications along the western front, while the Royal Navy tried to intercept German naval radio transmissions.[1] There were also efforts to send false radio signals, such as having shore stations send transmissions using ships' call signs and jamming enemy radio signals.[1] On the other hand, there were also attempts by the Ottoman side to jam Allied wireless communications during the Gallipoli campaign.[2]
World War II ECM expanded to include dropping chaff (originally called Window), jamming and spoofing radar and navigation signals.[1] German bomber aircraft navigated using radio signals transmitted from ground stations, which the British disrupted with spoofed signals in the Battle of the Beams. During the RAF's night attacks on Germany, the extent of electronic countermeasures was much expanded, and a specialised organisation, No. 100 Group RAF, was formed to counter the increasing German night fighter force and radar defences. Cold War developments included anti-radiation missiles designed to home in on enemy radar transmitters.[1]
In the 2007 Operation Orchard Israeli attack on a suspected Syrian nuclear weapons site, the Israel Air Force used electronic warfare to take control of Syrian airspace before the attack.[3] Israeli electronic warfare (EW) systems took over Syria's air defense systems, feeding them a false sky-picture. At the same time, Israel Air Force jets crossed much of Syria, bombed their targets and returned.[4]
Radar ECM
[edit]
Basic radar ECM strategies are (1) radar interference, (2) target modifications, and (3) changing the electrical properties of air.[1] Interference techniques include jamming and deception. Jamming is accomplished by a friendly platform transmitting signals on the radar frequency to produce a noise level sufficient to hide echoes.[1] The jammer's continuous transmissions will provide a clear direction to the enemy radar, but no range information.[1] Deception may use a transponder to mimic the radar echo with a delay to indicate incorrect range.[1] Transponders may alternatively increase return echo strength to make a small decoy appear to be a larger target.[1] Target modifications include radar absorbing coatings and modifications of the surface shape to either "stealth" a high-value target or enhance reflections from a decoy.[1] Dispersal of small aluminium strips called chaff is a common method of changing the electromagnetic properties of air to provide confusing radar echoes.[1]
Communications ECM
[edit]
Radio or communications jamming is the deliberate transmission of radio signals that disrupt communications by decreasing the signal-to-noise ratio to the point where the target communications link is either degraded or denied service.
Aircraft ECM
[edit]
ECM is practiced by nearly all modern military units—land, sea or air. Aircraft, however, are the primary weapons in the ECM battle because they can "see" a larger patch of earth than a sea or land-based unit. When employed effectively, ECM can keep aircraft from being tracked by search radars or targeted by surface-to-air missiles or air-to-air missiles. An aircraft ECM can take the form of an attachable underwing pod or be embedded in the airframe. Fighter planes using a conventional electronically scanned antenna mount dedicated jamming pods instead, or, in the case of the US, German, and Italian air forces, may rely on electronic warfare aircraft to carry them. ECM pods vary widely in power and capability; while many fighter aircraft are capable of carrying an ECM pod, these pods are generally less powerful, capable and of shorter range than the equipment carried by dedicated ECM aircraft, thus making dedicated ECM aircraft an important part of any air force’s inventory.
Future airborne jammers
[edit]The Next Generation Jammer is being developed to replace the current AN/ALQ-99 carried on the E/A-18G electronic warfare plane. Planned for adoption around 2020, it will use a small AESA antenna divided into quadrants[5] for all-around coverage and retain the capability of highly directional jamming.
DARPA's Precision Electronic Warfare (PREW) project aims to develop a low-cost system capable of synchronizing several simple airborne jamming pods with enough precision to replicate the directionality of an electronically scanned antenna, avoiding collateral jamming of non-targeted receivers.[6]
Selex ES has already developed an expendable active decoy that uses DRFM technology to jam RF-based threats.[7] (merged into Leonardo, the new name of Finmeccanica since 2017). The system, named BriteCloud, is self-contained within a small canister similar to a standard flare cartridge. The 55 mm format of the system has undergone flight trials with the Gripen aircraft, and the development of a 218 variant is at an advanced stage.[8]
Dedicated ECM aircraft
[edit]- EA-3 Skywarrior
- EB-66 Destroyer
- EC-130H Compass Call
- EA-6B Prowler equipped with ALQ-92 communications jammer, ALQ-100 multi-band track breaking system, and five ALQ-99 tactical jammer pods.[9]
- EA-18G Growler
- EA-37B Compass Call
- EF-111A Raven
- Tornado ECR
- J-16 D
- Su-24MP
- Yak-28PP
- Mi-8PP
Shipboard ECM
[edit]The ULQ-6 deception transmitter was one of the earlier shipboard ECM installations.[9] The Raytheon SLQ-32 shipboard ECM package came in three versions, providing warning, identification and bearing information about radar-guided cruise missiles.[9] The SLQ-32 V3 included quick reaction electronic countermeasures for cruisers, large amphibious ships, auxiliaries, and the RBOC (Rapid Blooming Off-board Chaff) launchers found on most surface ships.[9] The BLR-14 Submarine Acoustic Warfare System (or SAWS) provides an integrated receiver, processor, display, and countermeasures launch system for submarines.[9]
Infrared and acoustic analogies
[edit]
Infrared homing systems can be decoyed with flares[1] and other infrared countermeasures. Acoustic homing and detection systems used for ships are also susceptible to countermeasures. United States warships use Masker and PRAIRIE (propeller AIR Ingestion and Emission) systems to create small air bubbles around a ship's hull and wake to reduce sound transmission.[1] Surface ships tow noisemakers like the AN/SLQ-25 Nixie to decoy homing torpedoes.[1] Submarines can deploy similar acoustic device countermeasures (or ADCs) from a 3-inch (75-mm) signal launching tube.[1] United States ballistic missile submarines could deploy the Mark 70 MOSS (Mobile submarine simulator) decoy from torpedo tubes to simulate a full size submarine.[1] Most navies additionally equip ships with decoy launchers.[10]
See also
[edit]References
[edit]- ^ a b c d e f g h i j k l m n o p Polmar (1979), p. 121.
- ^ Vahibe Türkan Doğruöz (2022). Tevfik Rıza Bey (in Turkish). Çanakkale Savaşları Ansiklopedisi. ISBN 978-605-80897-7-8. Retrieved 6 December 2023.
- ^ Yaakov Katz (2010-09-29). "And they struck them with blindness". The Jerusalem Post. Retrieved 2025-03-16.
- ^ Israel Shows Electronic Prowess Nov 26, 2007, David A. Fulghum and Robert Wall, Aviation Week & Space Technology
- ^ "IN FOCUS: US Navy Next Generation Jammer proceeds, but F-35 integration deferred indefinitely".
- ^ Broad Agency Announcement Precision Electronic Warfare (PREW) STRATEGIC TECHNOLOGY OFFICE DARPA-BAA 09-65
- ^ "New Selex ES expendable active decoy 'britecloud' selected by saab for gripen fighter – DETAIL – Leonardo". uk.leonardocompany.com. Archived from the original on 2016-08-16. Retrieved 2016-07-20.
- ^ "Finmeccanica – Selex Es to hold britecloud trials with Gripen – DETAIL – Leonardo". uk.leonardocompany.com. Archived from the original on 2016-08-16. Retrieved 2016-07-20.
- ^ a b c d e Polmar (1979), p. 122.
- ^ "Terma SKWS Decoy Launching System" (PDF). Archived from the original (PDF) on 2013-04-26.
Sources
[edit]- Polmar, Norman: "The U. S. Navy Electronic Warfare (Part 2)", United States Naval Institute Proceedings, November 1979.
- Electronic Counter Measures (PDF) (Lee Pucker)
- A Down of Electronic Counter Measures- in Russian
- 100 years of ECM- in Russian
Electronic countermeasure
View on GrokipediaFundamentals
Definition and Principles
Electronic countermeasures (ECM) are techniques employed to prevent, delay, or reduce an adversary's effective use of the electromagnetic spectrum through offensive or defensive actions involving electromagnetic energy.[6] These actions aim to deny adversaries access to critical spectrum resources for detection, communication, and guidance systems by disrupting or deceiving electronic sensors.[6] Key principles of ECM include noise jamming, deception jamming, and passive measures. Noise jamming overloads enemy receivers with interference signals, such as random noise, to mask genuine target returns and reduce the signal-to-noise ratio, thereby obscuring detection.[6] Deception jamming involves generating false signals that mimic legitimate targets, leading enemy systems to process erroneous data like incorrect range or velocity.[6] Passive measures, such as deploying chaff or decoys, reflect or reradiate incoming energy without active transmission, creating false echoes or distractions to confuse sensors.[6] The electromagnetic spectrum plays a central role in detection systems, with radar operating across various frequency bands (e.g., X-band for precision tracking) to measure range, angle, and velocity via echoes, while communication bands enable data exchange between platforms.[6] ECM exploits these bands by introducing interference tailored to their wavelengths, such as broadband noise across multiple frequencies to counter agile radars.[6] ECM distinguishes between active and passive approaches: active ECM transmits energy to jam or deceive, as in noise or false signal generation, whereas passive ECM relies on reflecting or absorbing emissions without radiating power.[6] A fundamental metric for jamming effectiveness is the jammer-to-signal (J/S) ratio, which quantifies the relative power of the jamming signal to the target signal at the receiver.[6] Derived from the radar range equation , where is received power, is transmitted power, and are antenna gains, is radar cross-section, and is range, the J/S ratio simplifies to assess interference dominance by comparing jammer output against signal propagation.[6] The basic form is: Here, is jammer power, is jammer antenna gain, is signal power, is signal antenna gain, and accounts for losses like range and atmospheric effects; higher J/S values indicate effective jamming when exceeding receiver thresholds.[6]Classification of ECM Techniques
Electronic countermeasures (ECM) are primarily classified within the broader framework of electronic warfare (EW) into three main divisions: Electronic Attack (EA), Electronic Protection (EP), and Electronic Support (ES). EA encompasses offensive techniques that use electromagnetic energy to disrupt or deceive enemy systems, including jamming and deception methods. EP involves defensive strategies to safeguard friendly electronic systems from adversarial ECM, such as enhancing signal resilience. ES focuses on passive detection and analysis of enemy emissions to inform countermeasures, providing intelligence without direct engagement.[6][7] Within EA, subtypes include noise jamming, which overwhelms enemy receivers through interference, and deception jamming, which feeds false information to mislead tracking. Noise jamming variants are barrage (broadband coverage across a wide frequency spectrum), spot (narrowband concentration on specific frequencies), and sweep (scanning frequencies sequentially). Deception techniques encompass range gate pull-off (RGPO), which extends false range data to break radar locks, and velocity gate pull-off (VGPO), which simulates erroneous Doppler shifts. Expendables, another EA subtype, involve deployable decoys like chaff (reflective strips to clutter radar returns) and flares (infrared emitters to divert heat-seeking missiles).[6][1] ECM techniques serve strategic roles that are either offensive or defensive. Offensive applications, primarily through EA, aim to degrade enemy sensor and communication operations by denying spectrum access or creating confusion, thereby supporting strikes or evasion. Defensive roles, via EP and ES, protect assets by maintaining operational integrity against threats and enabling timely responses through emission analysis. However, limitations persist: self-screening occurs when EA interferes with the user's own systems, reducing situational awareness, while detectability of active jammers or expendables can expose positions to counter-detection or homing attacks.[6][7][1] The following table provides a taxonomy comparing the primary ECM divisions, highlighting their approaches, spectrum impacts, and examples:| Division | Approach | Spectrum Impact | Examples |
|---|---|---|---|
| Electronic Attack (EA) | Active transmission or deployment to disrupt/deceive | Broadband (e.g., barrage jamming spreads power over wide bands, reducing effectiveness per frequency) vs. narrowband (e.g., spot jamming concentrates power for targeted interference) | Noise jamming (barrage, spot, sweep); deception (RGPO, VGPO); expendables (chaff, flares) |
| Electronic Protection (EP) | Reactive or inherent design to resist interference | Primarily narrowband focus with agility across spectrum to evade jamming | Frequency hopping, signal encryption, beam correlation |
| Electronic Support (ES) | Passive sensing and analysis | Broad spectrum monitoring for emission detection | Radar warning receivers, signal interceptors for threat identification |