this time: Land-based air defences
|NATO used to have two lines of|
area air defence in Central Europe
There were rather few purchases of new equipment in Europe, so the overall quantity of air defences (and especially missile stocks) has diminished greatly. West Germany, for example, used to have really good air defences in the late 80's, but army air defences have disappeared almost entirely and the Luftwaffe's area air defences have become less and didn't age well.
We can categorise air defences in three conventionally accepted tiers (ignoring dedicated ballistic missile defences and tiny drones for now):
- very short range air defences, VSHORAD
- short range air defences, SHORAD
- area air defences*
VSHORAD is almost always an autocannon system (hardly ever a large calibre machinegun any more). These cannot be expected to be really effective past 3,000 m diagonal distance to a strike fighter, and 20 mm guns can even be considered largely ineffective past 2,000 m.
SHORAD is typically a missile system, including the portable missile systems (ManPADS). Heavy anti-air artillery such as 76 mm guns is almost nonexistent on land nowadays, but would de facto fall into this category as well.
VSHORAD and SHORAD may very difficult to suppress, particularly if their operation is independent of radars. Their primary usefulness is in forcing hostile strike fighters to fly at a safe altitude, such as 15,000 ft and forcing hostile attack helicopters to stay at a distance and minimise their line of sight exposure. Such systems only begin to kill great many combat aircraft IF their pilots were convinced that (V)SHORAD lethality is the lesser evil to them.
That's what area air defences can pull off, as they famously did during the Yom Kippur War (for a while).
Area air defences used to be incapable of engaging very low-flying combat aircraft. There was a theoretical ability to intercept combat aircraft flying at 100 ft only, but there was hardly ever the necessary line of sight for the radars.
Modern area air defence systems use active radar-guided missiles, though other guidances weren't fully replaced yet (due to costs). Active radar-guided missiles function in the air defence role about the same as in air combat. A booster stage adds the kinematic energy that in an air combat role the altitude and velocity at launch would have provided. Well, either a booster does so or the missile is decidedly shorter-ranged. The missile received radio datalink updates on the target (midcourse guidance), attempts to fly a kinematically advantageous intercept course (especially making use of the lesser drag in the thinner air at higher altitudes and flying to intercept instead of tail-chasing by pointing its nose at the target at all times). Finally the missile activates its own radar close to the target, locks on (after launch) and attempts to collide. With most such missiles there's a proximity fuse and warhead so a direct hit is not required for a kill. The active radar seeker can pick up targets that are not in line of sight with the air defence battery's radars, so the missile could even be launched with targeting data from aircraft or remote ground radars.
The same probability of hit (and kill) issues as mentioned in part I apply.
There were three most important developments:
- area air defence missiles may in theory replace (V)ShoRAD missiles because they can engage very low-flying targets now
- modern area air defence missiles have become terribly expensive (more than a million Euros a piece)
- area air defence missiles are now a very close equivalent and thus substitute to the favoured air combat missiles
#1 touches on the concept of repulsion. An area air defence missile that can engage a target about as easily at 100 ft altitude as at 10,000 ft altitude does not motivate the opposing combat pilots to fly at very low altitude. Area air defences that were unable to engage very low targets did so, and thus drove the hostile pilots into range of (V)SHORAD, but modern area air defence missiles such as SAMP/T would rarely do so (over flat terrain - mountainous terrains are trickier). This is a bit of a loss, especially for (V)SHORAD.
#2 is a problem for munition stocks IF the probability of hit turns out to be low. A missile priced EUR 1.5 million would still be a cost-efficient munition against a modern combat aircraft with a probability of hit below 0.05 (5%), of course. It's an entirely different question whether air forces leadership (usually officers who used to be combat aircraft pilots) would pursue large missile stocks in preference over a few more sexy combat aircraft, though. I suppose we can expect Western air defences (and quite likely also Russian air defences) to run out of area air defence missiles against a high end opposing force within days of arrival in a war zone.
#3 means that detection of hostile air power is the key for defensive air warfare. You do not really need super-sophisticated and thus super-expensive fighters for interceptor duties any more. All this may be substituted with big missile boosters and missile launch containers dispersed all over the country IF the detection is assured.
Futurists have prematurely believed that interceptors are obsolete in the 1960's already, but now there's a very strong case for the vision because the munitions are almost entirely if not entirely the same. An air-launched missile approaching a hostile strike fighter with a certain energy from a certain distance is almost indistinguishable from a land-launched counterpart flying next to it. In extreme cases they might differ only in serial numbers, as with the NASAMS system that uses air combat missiles as area air defence missiles.
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Readers may have noticed that I treat the still fashionable "network centric warfare" as self-evident. I think it should be so regarding defensive air warfare.
Radio datalinks may be unreliable on offensive (hostile airspace penetrating) missions, but on "our" side of the most forward hostile army brigades we should be able to enjoy sufficiently reliable radio communications. This permits a substitution of 100 m long copper cables by 100 km long radio datalinks (as the pioneers of wireless telegraphy did envision), and thus an aircraft or ground radar or ground-based infrared sensor may pick up a target, some IFF interrogator fails to get a satisfactory reply, a command centre may decide whether to engage and which launchers and munitions to use and then several launchers that ideally encircle the target may launch missiles which would receive updates en route to reach the vicinity of the target and lock on with the own sensor.
Networks like this would be rather too vulnerable 200 km ahead of the most forward friendly brigades to rely on, but 200 km behind them it should work just fine much of the time.
Area air defences can give a huge cost efficiency and general effectiveness superiority over hostile air power in defensive air warfare, and that has always been their purpose.Nowadays they technically are extremely similar to air-to-air missile systems.
*: A term for this that I saw much less often is HIMAD = high-medium air defence