Integrated Air Defence System
The Integrated Air Defence System is an air defence network built of multiple units operating cohesively to deny enemy air operations inside a designated zone. It frequently is comprised of Surface to Air Missile Systems, Anti Aircraft Artillery, and multiple radar systems, including early warning, acquisition, and target tracking, radar systems.
The key feature of an IADS is that all units work together to defeat a threat. Using superior Communications, Command and Control, a defence system such as artillery can attack a threat before it is detected by the threat, by using the Situational Awareness provided by the network it is part of.
To be considered an IADS, the system must possess three parts:
- Command, Control, Communications, and Intelligence (C3I): This is the "brains" of the system. It is here that the system leadership receive data on what occupies its airspace (be it friendly, neutral, hostile, or unknown). Data arrives at the command post (CP) in the form of radar data, visual observer's information, raw intelligence, voice information, etc. Here the information is collated and redunant information filtered (i.e. a radar track and information from a visual observer post may be the same entity), commanders determine what threat the entity poses, what assets the commander possesses to counter the threat, decides how to act, and passes the "shoot" order to the appropriate weapon system (see "Weapons" below). In most instances, the C3I is considered the most crucial link in the IADS.
There are multiple C3I in an IADS system. Generically, the country or area of interest is sub-divided into air defense zones (ADZ) or sectors. The country will have an overall countrywide IADS C3I. Each ADZ in turn will have their own C3I CP. Depending on the leadership philosophy, during wartime the strategic leadership may delegate authority to each ADZ C3I CP to act on its own. Or (in more authoritarian countries) the strategic leadership may retain "shoot/don't shoot" authority throughout the conflict.
- Sensors: These are the "eyes" of the system. The primary sensor type in an IADS is radar. However, many IADS (including many third-world countries) supplement these systems with visual observers. Information about tracks detected by the sensors are transmitted to the C3I CP where the information is collated and redundant tracks filtered (see "C3I" above). Some IADS have filter centers spatially located between the sensors and the C3I CP.
- Weapons: The "arms" or "teeth" of the beast. An IADS traditionally possesses surface-to-air missiles (SAMs), anti-aircraft artillery (AAA), fighters/interceptors, electronic jammers, and sometimes other (less traditional) weapons such as cyber-attack capabilities, and deception capabliities (think of a linguist from an adversary telling your pilots to turn left, while you are telling them to turn right. Who does he listen to and believe?)
It is important to understand the difference between having an air defense capability and having an IADS: a country may have multiple AAA systems and some fighters, but if they do not have the capability to coordinate these systems in defense of the country, resources are wasted (AAA and fighters attacking the same hostiles while other hostiles squeak through unengaged, or the worst-case "fratricide").
An IADS can be built up from many different systems, but typically they will include at least one form of SAM, and some form of early warning radar.
Surface to Air Missile Systems
Surface to Air missile systems represent a significant threat to aircraft. They comprise the majority of threats to aircraft also - SAMs require little training to use, are relatively cheap, and can be found almost anywhere. contrast with fighter aircraft, which require significant training to use, are relatively expensive, and require long runways to operate from.
Anti Aircraft Artillery
Anti Aircraft Artillery systems are rarely a significant threat to fast jets, due to their limited firing ceiling. Very few AAA systems are capable of hitting a target above 22,000ft. Due to their long Time of Flight (TOF) at this altitude, a maneuverable aircraft is capable of 'jinking' or making course corrections to prevent their being hit.
Having a radar system capable of detecting, and then tracking, threats is central to the concept of an IADS.