Electronic Warfare is a vast subject, but one which has a relatively clear definition as provided by the US Department of Defence’s Dictionary of Military Terms. This defines electronic warfare, often abbreviated to ‘EW’, as “(a)ny military action involving the use of electromagnetic and directed energy to control the electromagnetic spectrum, or to attack the enemy”.
The electromagnetic spectrum, specifically the radio segment of the spectrum, plays a vital role in military operations. The radio spectrum stretches from a frequency of one hertz to three terahertz. Radio is used for a myriad of military capabilities. These include radio communications, Satellite Communications (SATCOM), satellite navigation and radar. The radio spectrum has been used widely by militaries since the First World War. However, it was the Second World War which saw the use of radio increase, particularly via the adoption of radar.
It is a truism that every military innovation will prompt a countermeasure of some sort. The advent of the tank prompted the development of anti-tank weapons. The advent of airpower encouraged the growth of air defence weapons. Radio and radar prompted the development of EW as a riposte. For example, a radar-guided Anti-Ship Missile (AShM) will be countered by an EW system. This will use jamming (examined in the Jamming Devices/Jammers entry) to disrupt, degrade or destroy that missile’s radar.
EW has three subdivisions, electronic attack, electronic protection and electronic support. Electronic attack exploits radio signals to attack hostile radars or radios, SATCOM or satellite navigation. This is done to prevent these systems operating. During an air campaign, one air force may use electronic attack against it’s adversary’s Integrated Air Defence System (IADS). Combat aircraft may carry powerful jammers that direct radio signals against the IADS’ radars. This will aim to prevent those radars detecting the incoming aircraft. With the radars blinded, it will be harder to direct missiles, anti-aircraft artillery or defending fighters towards the incoming aircraft. Jamming may also be done to disrupt the IADS’ radio communications to prevent the management and coordination of responses.
Electronic protection is the harnessing of EW to protect against sensors or weapons primarily dependent on radar. Returning to our AShM example electronic protection may be used by a warship to protect itself against this threat. As the incoming missile is detected, the ship’s EW systems begin transmitting jamming signals towards the missile’s radar. The intention is to blind the missile radar to cause it to lose its target. Alternatively jamming maybe performed in such a way as to create a false, but more tempting, target in the missile’s radar. The missile may then opt to guide itself towards the fake target, believing it to be more lucrative and affording a better chance of a kill. To an extent, electronic attack and electronic protection are overlapping missions. The aircraft discussed in the example above are also protecting themselves against the IADS’ radar by attacking them.
Electronic support constitutes all activities related to facilitating EW. Electronic warfare depends on the continual collection and analysis of Signals Intelligence (SIGINT). SIGINT comprises Communications Intelligence (COMINT) on radio communications, SATCOM and radio networks. SIGINT also comprises Electronic Intelligence (ELINT) covering radars. Signals intelligence efforts collect parametric information on radars, SATCOM and radio communications. This includes details of what radio frequencies these systems use, where they are physically located, precise details on the composition of their radio signals and when these systems are active to name just four criteria. This can be done using a variety of capabilities. These can include SIGINT satellites in space listening to radio emissions emanating from Earth. It can also be done using covert vehicle or backpack SIGINT systems surreptitiously moving around a city. SIGINT enables electronic attack and electronic protection tactics to then be devised and implemented.
EW’s mission writ large is widening. The advent of cyberwarfare has given electronic attack an additional mission. Alongside jamming, electronic attack signals can be loaded with malicious code. This code can be injected into a hostile radar, radio or SATCOM terminal via an electronic attack. This may be done to attack these specific systems. Alternatively, it can be done to gain access to the communications networks they are connected to. This could allow the cyberattack to spread to targeted computers on that network. In the case of attacking a hostile IADS, a cyberattack could be injected through a radar. It may leave the radar alone but spread through networks targeting computers controlling the IADS. This has resulted in a morphing of EW terminology, in some cases, to reflect this new mission. As a result, terms such as CEMA (Cyber and Electromagnetic Activities) and EMSO (Electromagnetic Support Operations) have become fashionable in recent years to encompass the EW and cyber missions.