EW Academy · Contents · Chapter 11 · Nederlandse versie
Chapter 11: Electronic Counter Measures
The attacking side of EW: noise and deceptive jamming, cover pulses, decoys, chaff, flares, DIRCM, stealth and counter-IR tactics.
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11.1Introduction
Electronic Counter Measures (ECM) comprise all active and passive means of degrading or deceiving enemy sensors and weapons through the spectrum ( Electronic Counter Measures ). This chapter goes through the whole arsenal, ordered by what…
Read §11.1 →11.2Radar Jamming
Jamming is the deliberate transmission of electromagnetic energy to make a receiver unusable or to deceive it. For radar there are two fundamentally different families:
Read §11.2 →11.3Noise jamming
Noise jamming is shouting in a hall so that nobody can understand the speaker any more. It is crude but it works — except that everyone can also hear where the shouting is coming from.
Read §11.3 →11.4Deceptive jamming
Where noise jamming blinds the radar, deceptive jamming lies to it. The jammer receives the radar pulse, processes it and sends it back amplified and manipulated — as an echo that looks completely genuine but reports the wrong range,…
Read §11.4 →11.5Cover pulse jamming
Cover pulse jamming is deception with a concealing purpose: instead of pulling the track away , the real echo is buried . At (and around) the moment the real echo reaches the radar, the jammer transmits a wider, stronger pulse — noise or…
Read §11.5 →11.6Decoys
A decoy (false target) shifts the fight from the sensor to the choice of target : offer the weapon something that looks more real than the real target. Where jamming erases or falsifies information, a decoy adds a complete, physically…
Read §11.6 →11.7Chaff
Chaff is a cloud of thousands of wafer-thin, metal-coated fibres. Each fibre is about half a wavelength long and therefore reflects radar strongly: on the radar the cloud looks bigger than the aircraft or ship itself.
Read §11.7 →11.8Flares
A flare is a brightly burning cartridge that is hotter than the engine. A simple heat seeker chooses the hottest source in its field of view — and that is then the flare.
Read §11.8 →11.9Directional Infrared countermeasures
DIRCM (Directional InfraRed CounterMeasures) is the active, directed defence against IR-guided missiles: a small turret on the platform with a rapidly steerable mirror/telescope and a modulated IR source — nowadays practically always a…
Read §11.9 →11.10Stealth
Stealth (signature reduction, low observability) is the quietest form of ECM: no jamming, no deception, but making sure that the sensor receives too little signal to detect anything at all. It attacks the energy balance itself — the radar…
Read §11.10 →11.11Counter-IR tactics
Against IR threats — besides flares and DIRCM — tactics are a fully fledged countermeasure: the limitations of IR sensors ( Disadvantages of infrared ) can be actively exploited through flying behaviour and choice of environment. The main…
Read §11.11 →11.13EW receivers & DRFM under the bonnet
All the jamming in this chapter assumes that you first see and understand the threat. Behind every smart jammer — and every ESM sensor ( EW: Electronic Support Measures ) — there is therefore a receiver that has to find and characterise…
Read §11.13 →11.14Scenario: a MANPADS threatens a helicopter
A worked scenario that brings the counter-IR material together:
Read §11.14 →11.12Conclusion
The ECM arsenal at a glance, ordered by what it attacks:
Read §11.12 →