Russia's military presence in Syria has been steadily increasing over the past few months. Its warplanes are carrying out regular bombing raids against both Islamic State positions and, reportedly, other rebel groups opposed to the regime of Bashar al-Assad.
Its warships are launching cruise missiles against the same targets. But the latest reports are that Russia has also deployed its most modern electronic warfare system to Syria -- the Krasukha-4 (or Belladonna) mobile electronic warfare (EW) unit.
The Krasukha-4 is a broad-band multifunctional jamming system designed to neutralize Low-Earth Orbit (LEO) spy satellites such as the U.S. Lacrosse/Onyx series, airborne surveillance radars and radar-guided ordinance at ranges between 150km to 300km.
The system is reported to be able to cause damage to the enemy's EW systems and communications. The Krasukha-4 system works by creating powerful jamming at fundamental radar frequencies and other radio-emitting sources.
Lt General Hodges, the commander of U.S. Army Forces Europe, commented that Russia had demonstrated a high level of offensive EW proficiency against Ukrainian forces in Donbass using a first foreign deployment of the Krasukha-4 system.
Electronic warfare was first developed in World War II by the UK to defend against Axis bomber attacks and to defend Allied bombers from enemy surveillance systems. From that time there have been major technological breakthroughs and it is now acknowledged to be a major fighting element of armed forces worldwide.
The U.S., Russia and Europe invest billions of dollars each year in research and development in order to be the best at this essential military art, while Asian countries, led by China, also view electronic warfare as a vital area for research and development -- it includes electronic attack/support, electronic intelligence and signals intelligence.
In conflicts since World War II, electronic warfare has played an increasingly important role in major conflicts including Korea, Vietnam, Arab-Israeli, Balkans, Desert Storm/Enduring Freedom, Afghanistan, and Ukraine. It is effectively employed before the hard fighting begins to deny an opponent intelligence and the use of weapon systems.
Since the beginning of the Arab Spring, NATO countries led by the U.S. and directly supported by the UK have been actively gathering intelligence from countries employing EW assets -- including low-orbit surveillance satellites (Lacrosse/Onyx series), reconnaissance aircraft (NATO E3 Sentry (AWACS), USAF RC135-Rivet Joint, RAF's Sentinel R1 and Reaper drones -- and sharing intelligence information with the side being supported in the conflict.
Since the land grab by ISIS in both Iraq and Syria, NATO's EW assets have been targeting ISIS rebel fighting units, gathering intelligence to provide tactical target information and to actively engage ISIS by denying rebel units radio communication and surveillance information -- effectively blinding them electronically.
Sanitized intelligence information is shared with friendly forces including the rebel forces opposed to Syrian president Bashar al-Assad.
Until September 2015, Russia has been supporting Assad by supplying arms and training to Syrian forces. Bolstered by what it sees as Western indecisiveness on a Syria solution and by the West's inaction on Russia's military intervention in the Ukraine, Russia has decided to provide direct military air support to Syria. However, Assad's enemies comprise all rebel groups opposing his rule -- not just ISIS.
Russia is aware that NATO surveillance assets are able to monitor all Syrian-based Russian military aircraft activity including the rebel groups it is targeting, locations and weapons used.
Some of these rebel groups are directly supported by the U.S. and its allies which may result in Russia coming into direct political conflict with NATO.
To avoid being spied on, Russia needs to blind the eyes and silence the ears of NATO reconnaissance and intelligence-gathering assets so its actions are not open to close scrutiny.
So how effectively can the Krasukha-4 be used to cloak Russia's operations in Syria?
Its surveillance systems will not only be able to monitor NATO aircraft movement over Syria -- but also the types. From its intelligence it will be able to identify the frequencies and signal characteristics e.g. Lacrosse satellites and AWACS operate in S-band, Sentinel (and similar) in X-band, and drones in J-band.
Lacrosse/Onyx satellite positions are continually tracked by Russia. With this kind of intelligence detail the Krasukha-4 can be programmed to deny or disrupt NATO intelligence gathering.
But it is not all one way -- U.S. and NATO intelligence gatherers will have "electronic counter counter measures" (ECCM) to combat Russian interference -- and so the cat and mouse game of the Cold War is repeated. Intelligence gathering and radar-guided munitions will suffer some disruption and mistakes may be made but operations will continue.
ECCM may include being frequency agile and dodging the jamming signal or pointing the receiver antenna slightly away from the jamming source. There are also many tricks that can be played with signal processing that will mitigate the effects of jamming. Of course, it would also be possible for NATO to jam the Russian surveillance radar, denying them the identification and positioning of NATO aircraft -- but this would really ramp up the war of words with Vladimir Putin. We must also accept that the Krasukha-4 EW system is an essential part of the defense of Russian forces at the Latakia airfield in Syria and this must not be denied them.
Russia's military has long appreciated that "radio-electronic combat" is integral to modern warfare and accordingly that it offers a set of relatively inexpensive weapons that can potentially cripple an opponent's ability to sense, communicate and exercise command and control within a battle space.
The Syria conflict means Russia will now be able to test its new systems in live combat avoiding direct conflict with NATO. That will enhance overseas sales prospects of the Krasukha-4 system. NATO will also be able test its ECCM against another EW system, presumably with similar ends in mind.
David Stupples is Professor of Electrical and Electronic Engineering and Director of Electronic Warfare at City University, London. The views expressed are his own. CNN is showcasing the work of The Conversation, a collaboration between journalists and academics to provide news analysis and commentary. The content is produced solely by The Conversation.