SDB is neither slow nor easy target. SDB has very high maneuverability and can sacrifice altitude to gain supersonic, up to 550m/s.
http://www.doc88.com/p-7798267325595.html
Any maneuvering or course correction will reduce range significantly. So significantly that no random evasive maneuvering would make sense. Maybe around the last 3km at 50% range penalty.
It also won't gain back high velocity: For that again a range reduction penalty of lets say 20% is needed and it will not reach supersonic speeds by such a dive.
It's small and covered by metal, not easy to destroy unless hit directly. Missile proximity fuze can be triggered with 8-20 meters, not easy to be triggered by SDB at the best distance.
This is true for a dumb bomb. A SDB like PGM has fragil wings and control surfaces. It has such a low explosive power that a slight course error will make it totally useless, except maybe for softest kinds of targets.
Once its wings or control surfaces are damaged it will somehow fall short of its target.
A 250-1000kg dumb bomb on the other hand will fall @ 3-10km max. range and needs to be killed to not harm the target.
So this means, just damage a SDB and it will be a "mission kill".
Plus Irans AAA solution against SDB-like PGMs and CMs are timed fuses, no problems with proximity fuses.
Single 100mm Sarir shot has no chance to hit, you need 35mm AHEAD ammunition. Other weapon is not effective enough to counter SDB. China use China made weapon similar to Oerlikon 35 mm twin cannon.
A single Sarir round has a certain PK at a certain range against a certain target. Damage a SDB at 6km and it will most likely land too far away for any damage caused.
Iran has its own 35mm AHEAD munition but all its non-AHEAD munitions are effective against such targets.
China is a pioneer in the anti-CM/PGM business, AHEAD is just a potentially more cost effective solution to kill very hard targets.
Iran has a chain of such automatic AAA systems, the last net is the 23mm Mesbah series if 100mm and 35mm systems were not successful. At that stage a large burst of 23mm rounds will basically create a dense shrapnel wall trough which almost nothing can penetrate.
However for a PGM with the threat level of the SDB, the goal would be to mission-kill it cost effectively at extended range via 2-3 100mm rounds.
China has a 76mm AHEAD based system which is very large, but a real SDB-killer.
You will be hit not by several SDB, but dozons SDB for 1 batch, and there are much more batches coming after.
Thats true. The U.S is a country with a military that can indeed afford mass use of such PGMs.
However, effective range won't be that 100+ km in a combat scenario, that is my point. It will be still incredibly good 40-70km.
Use enough and Irans AAA counter systems can be depleted at one point.
This concept of a concentrated mass SDB attack is what has kept the U.S conventional airpower concept alive: A very cost-inefficient approach and only the U.S can even dare to think about it.
China CM-506KG has maximum range of 130km.
Iran has also such a system in development. I don't know if it is a good idea, it surely is useful for low-collateral damage and UAV scenarios against a low-capability enemy.
US has tens of thousands of GBU-39. Get prepared, your air defense system will be facing saturation attack.
True. Unfortunately the U.S wants to go for hypersonic missiles for use against high value targets. Iran has been and is handling SDB-like threats, most recently with AHEAD munitions.
The SDB threat is so well countered by Irans AAA solutions that no Pantsir or even Crotale like missile-systems are necessary against this class of low-kinematic/explosive performance PGMs.