Picture This

This is an article published in our February/March 2017 Issue.

traffic control radar harris
IADS can also be required to integrate information gathered by non-military sensors, such as civilian air traffic control radar, into their RAPs. (Harris)

Integrated Air Defence Systems (IADS) are at the cornerstone of protecting a nation’s air space. The need to know what is going on in the skies above federates sensors, weapons and communications, calling on innovative approaches and techniques.

The soft hues of blue and green flickering on radar screens, the delicate drone of the computer fans, subdued lighting and the muffled calm chatter of controllers into their headsets, the response to their instructions being inaudible to the passive observer, creates a strangely soothing ambience in an IADS air operations centre. Yet, as the observer appreciates this resplendent display of calm and collected professionalism, at the back of their mind is a certainty that this environment will become energised with focused, yet determinedly professional, should an anomaly in the form of a uncooperative aircraft, grace their radar screens. The track of this potential threat will become immediately apparent and attempts, possibly fruitless, will be made to establish radio contact with the aircraft. Then, following a tightly defined set of protocols, many of which will remain understandably secret, a course of action will commence by which a fighter and its crew maintained, on Quick Reaction Alert, will be scrambled to intercept the aircraft and escort it away from national airspace or, in the most extreme case, to fire on the offending aircraft and shatter it out of the sky.

The subdued atmosphere of an IADS command and control centre belies the concentration and professionalism of its operators whom are integral to safeguarding a nation’s skies. (Saab)

IADS are the silent guardians of a nation’s airspace. Using radars to watch the skies and radio communications to divine an aircraft’s intentions, they are tasked with protecting the air from a diverse array of threats ranging from an aircraft which may have been hijacked with the risk of being deliberately crashed into a target on the ground, to a full-scale hostile attack involving numerous strike packages of military aircraft directed against strategic targets. In the Asia-Pacific, several recent and ongoing events have refocused the air power agenda on the need for robust IADS which federate the command and control centres with ground-based air surveillance radars and ground-based air defence systems such as Surface-to-Air Missiles (SAMs) and Anti-Aircraft Artillery (AAA), along with fighters held at QRA at airbases around the country.

modern IADS Saab
The complexity of a modern IADS is highlighted in this image which illustrates the disparate number of communications systems which must ‘knit’ together its various aspects to ensure a nation’s air sovereignty. (Saab)

Lessons Learned

Examples of these events have included the disappearance of Malaysian Airlines flight MH-370, a Boeing 777-200ER airliner en route from Kuala Lumpur International Airport to Beijing Capital International Airport on 8 March 2014; an event we examine in the April edition of AMR. This flight disappeared from Tentera Udara Diraja Persekutuan (TUDP/Royal Malaysian Air Force) radar coverage while over the Andaman Sea, never to be seen again. The loss of the jet arguably underscored the need for national IADS across Southeast Asia to be capable of sharing elements of the Recognised Air Picture (see below) with one another to be able to follow from one country’s airspace to another, an aircraft which maybe behaving erratically. Secondly, the People’s Republic of China’s (PRC) increasingly assertive strategic posture in the East and South China Seas (please see Veerle Nouwen’s article Are You Going to Scarborough Shoal? in this issue for more discussion of the security situation in these areas) should prompt a rethink across the region regarding how to track potentially hostile aircraft using a multilateral approach.

The People’s Liberation Army Air Force (PLAAF) has displayed worrying competence in violating national airspace throughout the region over the past year: In June 2016, PLAAF aircraft, notably Xian JH-7A fighters violated Indian airspace in the Aksai Chin region of northern India and Eastern China. Local Indian media reports stated that the jets violated Indian airspace across the Sino-Indian border in the region. Meanwhile, in September 2016, the Japan Air Self Defence Force (JSADF) scrambled fighters to escort PLAAF aircraft, believed to include four Xian H-6K strategic bombers according to Japanese media reports, away from the Senkaku Islands in the East China Sea. The Senkaku Islands are under Japanese sovereignty, but claimed by the PRC and the Republic of China. More information regarding the current status of air forces across the Asia-Pacific can be found in Alan Warnes’ The China Syndrome directory article in this issue.


According to open sources, Japan uses the JADGE (Japan Air Defence Ground Environment) IADS which became operational in 1989, and which provides full radar coverage over the country’s airspace. The TUDP, meanwhile, uses Thales’ MADGE (Malaysian Air Defence Ground Environment) IADS, while the Indian Air Force (IAF) has the Integrated Air Command and Control System (IACCS), the implementation of which was led by Bharat Electronics Limited (BEL). There acronyms maybe as different as their respective geographical locations, but the modus operandi of these disparate IADS share distinct resemblances. First and foremost, their overarching task is: “the detection, tracking and identification of air vehicles,” according to the UK Ministry of Defence (MOD) paper Air Surveillance for Air Battle Management. This task is achieved by generating a Recognised Air Picture (RAP). Once again, definitions can vary, but broadly speaking, the RAP “is an electronically produced display compiled from a variety of sources including (radar) and ESM (Electronic Surveillance Measures). It covers a three-dimensional volume of interest in which all detected air contacts have been evaluated against specific threat parameters and recognition criteria, and then assigned an identification category and track number,” so stated the UK MOD publication Joint Air Defence.

While the use of radars, notably ground-based air surveillance radars, but also the radars used by Airborne Early Warning (AEW) and fighter aircraft forms an integral part of an IADS, there is an increasing use of ESMs as constituent components of an IADSs. For example, passive radar monitors the electro-magnetic spectrum for electro-magnetic emissions from aircraft, which can include Very/Ultra High Frequency (30 megahertz to three gigahertz) voice and navigation radio transmissions, and radar transmissions, to locate an aircraft through a process of triangulation. It is noteworthy that in 2011, Vietnam purchased four Vera-E passive radars from ERA/Omnipol which, according to the firm, can detect radio frequency transmissions from aircraft at a range of up to 270 nautical miles (500 kilometres), with the ability to track up to 300 targets. Although not officially confirmed, it is possible that these Vera-E passive radars are now in service with the Vietnam People’s Air Force Air Defence Divisions responsible for protecting that country’s airspace.

JASDF’s JADGE network.
Japan has achieved total radar coverage of its territory as part of the JASDF’s JADGE network. This diagram illustrates the surveillance range coverage of these radars. (Toshiyuki Shikata)

Take the RAP

Beyond the need to generate a RAP, flexibility should be at the core of any IADS. Saab told AMR, via a written statement that: “A modern IADS should be able to handle a number of different situations. The system will be used 99 percent of its time for peace time activities and not only for military exercises. These activities for an air force can be to support civilian society in the detection of various illegal activities (illegal fishing or drug smuggling, for example) disaster relief or rescue operations.” Although not confirmed by the firm, Saab is believed to have supplied its 9Air family IADS to the Royal Thai Air Force (RTAF). This ‘knits’ together the RTAF’s Saab JAS-39C and Lockheed Martin F-16A fighters, its Saab 340 Erieye AEW aircraft, and its Selex Kronos C-band (5.25-5.925GHz) ground-based air surveillance radars, to name just three platforms/sensors, to help safeguard the skies of Thailand. However, an IADS is not only used to generate a RAP and to enable controllers to vector fighters towards a potentially hostile contact, or to direct SAM or AAA fire, Saab’s statement continues that it must also: “support the operators during all stages of a mission assignment from planning to execution and debriefing.”

Breaking this down, the firm continued that: “In the planning stage, the system displays information of available resources likes sensors, weapons, airspace and airfields and provides tools for how to utilise these resources efficiently during the course of a mission.” Once a plan is being executed, the statement continues, the IADS: “has two overarching tasks, primarily to collect and present air surveillance radar information and to use that data to take decisions and execute actions based on the situation.” Precision is paramount in all aspects of IADS design: “The tempo (of air operations) is high and decisions need to be taken swiftly and based on trustworthy, accurate information.” In a nutshell, as a Thales statement to AMR articulated, the role of an IADS is to network “all the necessary sensors to have the most precise situational awareness and connect all the effectors (weapons and accompanying platforms) whatever they are in order to enable the customer to perform in airspace protection.”

Saab’s 9Air family
This diagram illustrates the constituent parts of an IADS, in this case Saab’s 9Air family, and also its complexity in terms of the sensors, effectors and communications it employs. (Saab)

Alongside the sensors, robust and secure communications are a vital element of IADS design. To this end, Saab stressed that: “there needs to be a nationwide IP (Internet Protocol) network to connect and combine all different sensors and command and control centres.” As well as having several radars positioned around the country to generate the RAP, not to mention passive sensors such as the Vera-E discussed above, plus radar pictures generated by civilian air traffic control centres and airports. Furthermore, a modern IADS may have a federated structure with Sector Operations Centres (SOCs) positioned around the country, each of which is responsible for a particular ‘slice’ of a nations’ airspace. These SOCs may in turn send their local RAP up to a National Air Operations Centre which federates these, disparate, local recognised air pictures into a single, national RAP. Taking the example of the IACCS, this employs ‘nodes’, according to open sources, five of which cover the western approaches to India from Pakistan to protect against any incursions from that direction, with a further 14 to cover eastern, central and southern India, and to cover India’s Andaman and Nicobar Islands in the Bay of Bengal. Sources continue that these nodes are connected to one another using the IAF’s Air Force Network (AF Net) which has an encrypted IP network as its backbone.

Beyond IP networks, and conventional V/UHF voice radio communications, Tactical Data Links (TDLs), the Saab statement continued, are vital for an IADS. TDLs can operate across V/UHF radio links to provide fighters, for example, or SAM batteries with track data regarding hostile aircraft. The JADGE is instructive in this regard as its employs the Link-16 TDL used throughout the North Atlantic Treaty Organisation (NATO) and allied nations which provides a UHF (960MHz to 1.2GHz) TDL for the conduct of air operations. As open sources note, the employment of the Link-16 protocol forms the key part of connecting the JASDF’s General Electric AN/FPS-6, Bendix AN/FPS-20A and J/FPS-2/3A/4/5 ground-based air surveillance radars located at 28 sites around the country, which develop the RAP at the JASDF Air Defence Command at Fuchu airbase in Tokyo. The Saab statement continues that: “there is also a great benefit to use TDLs to assure situational awareness for commanders and the ability to control military assets.” However, Link-16 is not the only option on the table as far as TDLs are concerned. Several firms offer proprietary TDLs to customers which can be tailored to their requirements.

Moreover, TDLs such as Link-16 tend to be available only to NATO and allied nations, and hence might be beyond the grasp of some nations in the Asia-Pacific. Avishay Izhakian, the deputy general manager for marketing and business development at Israel Aerospace Industries’ (IAI) ELTA Systems division notes that: “One of our customers in the Asia-Pacific does not use Link-16, but has a network which is much more advanced in terms of functionality.” One of the limitations of Link-16 is bandwidth. Publicly available documents note that it can provide communications with bandwidths of between 2.4 kilobits-per-second (kbps) up to 16kbps; a bespoke TDL from a firm such as IAI gives the customer additional options in procuring TDLs which offer the functionality that they need. Moreover, IAI can also provide a range of other communications to support an IADS: “We generally use voice High Frequency (three megahertz to 30MHz) and VHF communications, UHF communications for data and also satellite communications,” Mr. Izhakian continued.

In this respect, the ‘horses for courses’ aspect is important. The communications used are highly dependent on the IADS’ architecture and provenance. For instance, the JASDF found it expedient to use a network in part based on Link-16 when the JADGE was rolled out in the 1990s. India, on the other hand, has employed the AF Net system using an IP approach, reflecting the state-of-the-art when the IAF commenced the implementation of this network at the end of last decade.

Lots of COTS

Away from sensors such as radars, IADS designers have to consider the hardware constituting an air command and control system. This, according to Saab, typically includes “operator consoles with display screens, cryptographic equipment, services and communications equipment.” The company added that a stress should be placed upon using Commercial-Off-The-Shelf (COTS) equipment whenever possible, such as computer servers for instance. This, Saab argued, is because the IADS architecture should be “hardware agnostic” regarding the sensors and communications which it must federate and that, throughout the IADS’ life: “adaptations should be done on the software side (as) new functionality and technology needs to be inserted in incremental (stages) to increase operational effect.” Such an approach will greatly ease the integration of a new ground-based air surveillance radar, or SAM system which has to connect with the IADS during its service life. Connecting such a system into the IADS via a software upgrade, rather than completely redesigning the IADS’ hardware, will help to reduce the system’s lifecycle costs.

traffic control radar harris
IADS can also be required to integrate information gathered by non-military sensors, such as civilian air traffic control radar, into their RAPs. (Harris)

The consequence of the approach described above is that the advent of brand new IADSs in the Asia-Pacific may be few and far between over the coming decades. Instead, existing systems maybe continually upgraded and augmented as new sensors, weapons and software becomes available. In this regard the approach is set to be evolutionary rather than disruptive, ever improving the safety and security of the skies.