Electronics play a significant role in modern day air operations, both in the offensive as well as defensive roles, wherein aircraft survivability holds the key to improving overall effectiveness of air battle

In a very broad sense, Electronic Warfare (EW) generally refers to “any action involving the use of the Electro-Magnetic (EM) spectrum or directed energy to control the spectrum, attack an enemy, or impede enemy assaults via the spectrum”. The purpose of EW is to deny the opponent the advantage of, and ensure friendly unimpeded access to, the EM spectrum. EW can be applied from air, sea, land and space by manned and unmanned systems, but its biggest impact is felt in the conduct of air operations. Three major categorisations in the vast area of EW include: Electronic Surveillance (ES), Electronic Protection (EP) and Electronic Attack (EA).

Electronics play a significant role in modern day air operations, both in the offensive as well as defensive roles. Aircraft survivability in the overall electronic spectrum is a key issue for improving the overall effectiveness of air battle. Airborne EW, when combined with stealth or low observable technologies, is being recognised to be one of the most effective techniques for increasing aircraft and aircrew survivability.

Electronic Intelligence

Among the three major subdivisions described earlier, ES generally involves passive search for locating, localising and identification of sources of intentional/unintentional radiation of EM energy for the purposes of immediate threat recognition, targeting, planning and conduct of future operations. An overlapping discipline, Signals Intelligence (SIGINT) is the related process of analysing and identifying the intercepted frequencies. SIGINT can be further categorised under ELINT (Electronic Intelligence), COMINT (Communication Intelligence) and FISINT (Foreign Instrumentation System Intelligence).

EA, or Electronic Countermeasures (ECM), involves the offensive use of the electromagnetic energy, or anti-radiation weapons to attack personnel, facilities or equipment with the intent of degrading, neutralising or destroying enemy’s combat capability. EA operations, however, can be detected by an adversary due to their active transmissions. Examples include communications jamming, Integrated Air Defence System suppression, Directed Energy/Laser attack, expendable decoys (for instance, flares and chaff), and Counter Radio-Controlled Improvised Explosive Device systems.

EP, also known as Electronic Protective Measures or Electronic Counter Countermeasures (ECCM), involves actions taken to protect personnel, facilities and equipment from any effects of friendly or enemy use of EM spectrum that degrade, neutralise or destroy friendly combat capability. EP should not be confused with self-protection (jamming). For example, the use of flare rejection logic on an infra-red (IR) missile to counter an adversary’s use of flares would come under EP, whereas, use of flares would come under self-protection (or defensive EA). While Defensive EA actions and EP both protect personnel, facilities, capabilities and equipment, EP by itself protects from the effects of EA (friendly and/or adversary). Other examples of EP include spread-spectrum technologies, use of Joint Restricted Frequency List (JRFL), emissions control (EMCON), and low observability or ‘stealth’.

Historically Speaking

Airborne EW is as old as the application of electronics in air operations. During World War II, as soon as the ground-based radars were deployed for the detection of incoming enemy air raids; both allies as well as the Germans quickly developed a number of countermeasures to degrade the radars, like chaff, which are still employed. The Allies also developed radar jamming. Just as countermeasures were developed to counter radar, counter-countermeasures were developed to negate the countermeasures. For example, Germany began to use radar frequencies that were not affected by the Allied chaff. However, towards the end of the Great War, ECM had certainly reduced some of the advantages that radar conferred upon air defences. Allied bombers employing ECM during raids on Germany suffered attrition rates 25 per cent less than the bombers without onboard ECM.

In the post World War II era, the electronic game of ‘cat and mouse’ continued to be taken to ever higher levels, with the US taking the overall lead in all departments of EW. For instance, in the Vietnam war in the 1960s, EW became extremely important to neutralise a flood of North Vietnamese surface-to-air missile (SAM) batteries, supplied by the then USSR. Modified Phantom fighters, F-4G Wild Weasel aircraft, were used extensively to locate, identify and destroy the SAM sites. To counter radar-guided SAMs, one of the basic tactics for the strike aircraft is to remain either above or below the radar envelopes. However, with a combination of SAM-II and SAM-III deployments covering both the high level as well as low level envelopes, it became necessary to eliminate the threat by employing different methods within the overall ambit of EW.

Several techniques have evolved over a period of time to improve aircraft survivability, such as Suppression of Enemy Air Defences (SEAD), use of anti-radiation missiles and airborne jamming platforms. The US Navy developed an exclusive EW aircraft, named EA-6B Prowler to carry out SEAD missions in the form of escort/area jamming with its onboard ALQ-99 receiver, ALQ-99 pod-mounted jamming equipment and USQ-133 system for communication jamming. The US Air Force (USAF) experimented with the F-111 airframe to create a dedicated EW aircraft, the EF-111A Raven. Equipped with AN/ALQ-99E, it was designed to essentially carry out similar SEAD missions as the US Navy’s EA-6B Prowler aircraft.