Thread by @DuitsyWasHere

New thread: Why did Abqaiq's air defenses fail?

First, updated maps of the air defense sites at Abqaiq. First one is April 2019 (the date of the image), the second is how forces were deployed as of this week.

This thread will by much more analysis, much less satellite imagery.

Let's get some misconceptions out of the way:
-The Saudis are not incompetent
-Patriot is not useless
-The attackers were not merely "lucky"
-I am not actually air defense expert

In fact, I don't think the Patriot battery, or any other system south of the facility (had they even been there), ever had a chance to participate.

Two words: ground clutter.

Also, the Patriot radar might not have been turned on.

https://twitter.com/PutinIsAVirus/status/1174516823334764545?s=20

Look at this satellite image.

The attacking drones flew in at low altitude (perhaps no more than 200 meters) from the north or northwest. The Patriot radar's line of sight was obscured by the oil facility, its residential and support buildings, and a village further to the west

Granted, the AN/MPQ-53 is supposedly pretty good at dealing with ground clutter, but it still can't see through buildings, storage tanks, or electrical pylons.

Imagine watching a bird fly through a forest, trying to precisely predict its future flight path.

This (and radar horizon) is why early warning radars are usually mounted on hills). It is also one reason why Russia makes a mobile, 23-meter-tall mast for the S-300 radars 0 to position the radars above obstacles.
ausairpower.net/APA-40V6M-Mast…

Without the Patriot radar, and since no one else detected the incoming attack, Abqaiq's defenders were entirely reliant on the Shahine and Skyguard radars, which have a 20 km range against full-sized aircraft.

Against a drone, this would be much shorter.

If we assume that Iran's suicide guitar pick... err delta-wing drone is detected at 10 km and flies at an especially lackadaisical 75 m/s (167 mph), the defenders will have slightly more than two minutes between detection and impact.

In those two minutes, the crew must:
-determine they are under attack
-perform the necessary actions to begin an engagement
-select the target
-select a means of engagement (which missile or gun to fire
-get the crew of that particular firing unit to wake up and do their job
-etc

If you want an idea of what this entails, take a look at the documentation for SAM Simulator. Interpreting radar returns isn't necessarily intuitive, and the control systems themselves can be an absolute nightmare.

sites.google.com/site/samsimula…

This is why the US Navy's Phalanx close-in weapons system (CIWS) has a fully automatic mode (i.e. without a human in-the-loop) - because engagement times against sea-skimming missiles (which travel much faster than 75 m/s) are often a minute or less.

I am going to continue this, but it is 1 AM, and I'm starting to make too many typos.

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