After the first Gulf war, I had a chance to visit Israel where I saw significant damage caused by primitive SCUDs fired by Saddam. Every one told me that the much praised Patriots (were probably older versions) were abysmal failures in intercepting the incoming SCUDs.
Looks like you and I have different perspectives on the Patriot system of Desert Storm.
First -- The system was not originally designed to be against ballistic missiles. Different methods of attacks required different means of defense. Target tracking and interceptor maneuvers depends on the different modes of intercept navigation, aka 'guidance laws', a few examples below...
Proportional navigation - Wikipedia, the free encyclopedia
Proportional navigation (PN) (Pro-Nav) is a guidance law used in some form or another by most homing air target missiles. It is based on the fact that two vehicles are on a collision course when their direct Line-of-Sight does not change direction. PN dictates that the missile velocity vector should rotate at a rate proportional to the rotation rate of the line of sight (Line-Of-Sight rate or LOS-rate), and in the same direction.
GBU-12 Paveway II - Wikipedia, the free encyclopedia
Paveway II laser guided bombs use what is known as "bang bang" guidance. This means the bomb's fins deflect fully, rather than proportionally when it is attempting to guide to the laser spot. For example, if it sees the laser spot and determines that it should make a change it deflects its fins until it has over-corrected and then it deflects back the opposite direction creating a sinusoidal type of flight path. This type of guidance may be less efficient at times.
Other derivatives are augmented PN, extended PN, and if you wish to delve further, give this book a try...
Amazon.com: Modern Navigation, Guidance, And Control Processing (9780135962305): Ching-Fang Lin: Books
I have seen better texts, but for the laymen, this one is 'just good enough' for interested readers to see there are more to these weapons than just hardware figures. Just like many sub-systems in radar detection, there are engineers who spent their entire professional careers doing nothing but working with these guidance laws and they retire to handsome boathouses in the Florida Keys, drinking and ogling girls all day long.
Second -- The Patriot system of Desert Storm was never meant for wide area defense. The system was supposed to defend vital and small areas, such as an electrical power station, at the expense of the city the station is working for, if necessary. Same for an air base, at the expense of nearby civilian enclaves, if necessary. That is the cruel calculus of war.
Finally -- There is no avoidance of ground damages. Everything returns to Earth. What does the word 'significant damage' really mean? Compare to what? To the actual warhead detonation? For the successful interceptions, and there were some, the system worked beyond expectations. The interceptor successfully homed in on a target whose behaviors were not part of its intercept algorithms. So when it was successful, what do you think the target's remains are going to do? Disappeared into another dimension? No...Those debris will fall to Earth and their velocity will inevitably create damages to human structures. The law of gravity rules.
The SCUD defense in Desert Storm was a political act, not a military one. In the cruel calculus of war, the Patriot system would not have been deployed to defend civilians. The SCUDs were too inaccurate when each missile's CEP were in the thousands of meters. But for the few successful intercepts, we learned there could be more to the system, from creating new guidance laws to improving the hardwares, that would create a new ballistic missile defense.
