What is an Air Defense System? What Does It Do?

The system we call an Air Defense System consists of a complex structure consisting of command and control vehicles, ammunition transport and loading vehicles, radars and launcher vehicles called launchers, which are expressed in different concepts such as "Battery, Squadron, Battalion, Company, Squadron, Unit, Unit" etc., the number and general characteristics of which vary depending on the production of the systems.

Figure -1 Airport and port equipped with a sample Air Defense System

In any Air Defense System, the most important element of the system, that is, the brain of the system, can be defined as "Radar". This is because radar performs the detection, identification and tracking functions of targets. In simple terms, radars are instruments that send signals to the air, sea, land or space according to their intended use, and detect their targets by reflecting these signals back. Although the range of a radar is expressed in various numbers, this distance varies in direct proportion to the "Radar Cross-Sectional Area (RCS)" of the target it is trying to find in the search area. 

RCS values are a phenomenon that varies depending on the physical and chemical structure of all kinds of vehicles, whether they are airplanes, ships, tanks, etc. For example, the RCS value of an F-16 fighter jet is stated as 1.2 m2 in open sources. As another example, F-22 fighter jets with Stealth (low visibility) feature are stated to have an RCS value of 0.0001 m2. Depending on these values, the detection range of a radar varies from target to target.

For example, a radar with a maximum range of 400 km cannot see everything within 400 km. 

In addition, HSS radars have an extra disadvantage. Due to the fact that they are land-based, landforms affect these radars more. We can liken this to a simple cell phone base station. If you are in a depression relative to the cell tower, your signal will weaken or disappear. If you are clearly connected to the base station, you can communicate as far as the system can reach.

Figure -2 Iron Dome Air Defense System

Figure -3 Oerlikon Air Defense System 

HSSs detect, identify and track the enemy thanks to these radars, and then engage (lock on) the enemy if necessary with the missiles in the system.

"What are the development objectives and advantages of these systems?"

The purpose of the development of HSSs is to respond to air elements with defense systems deployed in a fixed location instead of constantly raising an opposing air element. In this way, the distance that the system can control in the area where the system is deployed can be continuously monitored and there is no need for any external flying element.

Not all ASWs can provide the same level of protection against all types of threats. Therefore, there are different types of ASWs. These types are divided according to altitude and range. If we make a ranking from the lowest layer to the top layer;

"Very Low Altitude Air Defense Systems" take the first place. Although these systems are mostly in the anti-aircraft class, they can also be used against missiles and rockets within their range. Their primary targets are enemy elements flying at low altitude at low speeds and cruise missiles. As mentioned earlier, the success rate of these systems varies in proportion to the capabilities of the enemy. Their range is approximately 8 km or less. The ceiling altitude is around 4-5 km.

"Low Altitude ASW" is in the second place. These systems have an interception range of approximately 10-15 km. There is not much difference with the first "Very Low Altitude ASW". Their maximum altitude varies between 5-10 km. Their targets and success rate are the same as the first ranked systems.

In the third place is the "Medium Altitude ASW". The systems in this class generally have a range of 15 to 50 km and a maximum altitude of 10-15 km. Although they do not differ much from the other two classes in terms of their targets, some models can be effective against short-range ballistic missiles and artillery rockets. 

In addition, their interception effect against air-to-surface missiles is generally low.

The fourth and final category is "High Altitude ASW". The systems in this category can reach very long distances of 90, 120, 250 km, well above 50 km. They are effective against ballistic missiles as well as systems at other altitudes.

As can be seen, all of the systems have similar objectives in general, but there are also different HSSs specially developed for targets at different altitudes.

There is no need for Medium/Low/Very Low ASW systems just because there is a High Altitude ASW system. It is also not correct.

Figure -4 A sample Air Defense system structure

Figure - 5 Coverage area in the Aegean Sea created by Greece by combining these HSS and Radars

What are the weaknesses and structural disadvantages of air defense systems?

As we mentioned at the beginning of our article, HSSs have an advantage in protecting a fixed area due to their land-based deployment, but they also have a disadvantage for the same reason. As we mentioned in the section on the working logic of ASWs, radar vehicles are the brains of ASWs. Therefore, if the radar of an ASW is hit, the entire system will most likely become inactive (unless there are backup radars or measures to prevent the system from shutting down).

Another disadvantage is again radar-related. Since these systems are land-based, the radars are naturally at ground level. Therefore, as explained above, the visibility of the radars is restricted.  This is not only related to landforms. Even at sea level, it is difficult for radars to detect elements below a certain altitude due to the roundness of the earth. For this reason, HSSs prefer to work on a common network rather than working alone. 

These networks are formed by combining different elements such as more capable ground radars, airborne radars, AWACS aircraft, reconnaissance and surveillance satellites. Thanks to the network, the PMSs perform their missions not only with their own radars, but also according to the data obtained by all detection systems included in the network.

Systems that are not part of such a network have a relatively weaker defense capability against ballistic missiles, cruise missiles and low-altitude air elements.

Moreover, shooting down a ballistic missile is much more difficult than shooting down an airplane or helicopter. This is because ballistic missiles, especially those that enter the dive phase, which we call the terminal phase, reach incredible speeds (tens of kilometers per second). It is also very difficult to stop an object that reaches such extraordinary speeds.

Another weakness or disadvantage is that this system can be completely dysfunctional depending on the ammunition used in enemy attacks. For example, it is very, very difficult to develop a system that can stop an artillery shell, which is similar to trying to shoot a mosquito with a pistol. 

The last issue that we can count as a disadvantage or weakness is the endurance limit, which we call the saturation point. 

Every system has a saturation point and if this limit is exceeded, the system cannot provide the expected protection. We can express this with an example; a system with 64 missiles ready for firing will be penetrated in any way with the ammunition that will be fired in increments of more than 64 over the area it is obliged to protect. And it is already impossible to hit all 64 munitions to be fired here. More or less a breach will be made in the system. If the number of ammunition fired / the number of attacking air elements increases further, the survivability of the system will decrease in parallel.