Mr. T (MrT4) said:

SPAAG itself with gun only is kinda hard to keep as an antidrone defense as modern optics enable drones to stay out of spaag range fairy easy . 

depends on the drone I'd say. Guns are very valid against the quadcopters etc IMO.

I am actually thinking a 4 panel FP version of the Giraffe 1X for both scan and FC with EO as secondary system. Plus 2*4 StarStreak and 2 laser designators for StarStreak (laser beam rider) for more target engagement capability. As regards the gun - Gepard seems to be getting APDS-T, so is completely hittile. Drones get downed with 6 round bursts. AAA-T ammo should be able to do that with a single round.

So

1x40mm

2x4 StarStreak

Giraffe 1X FP

AMAP-ADS

Electrotoptix

sound good?

And yes, not cheap.

I have been thinking further about how I'd configure an anti drone system

All of the above as per a modern SPAAG, but also an ECM system and probably a high ROF MG for the wee drones

Remember the little folding 40mm drones? Imagine a slightly larger one with a FLIR Boson based 640 res IIR sensor. When a drone is detected passively by a staring IIR sensor or MMW radar on the host vehicle, a Chaff/Flare like dispenser kicks one out, the arms and motors unfold, and it zips off to the target queued by the APS, destroying it with a little golf ball sized warhead.   A dispenser might be the size of a piece of luggage and easily hold 25+ drones.

Because it's intercepting a known target at relatively short range and isn't returning, it can trade endurance for acceleration.

https://www.youtube.com/watch?v=YHvC3KRTxO0
 

I don't thing the use of counter drones is a viable and especially cost effective option.
To be really reliable they sensor and guidance would need to be rather complex. In addition the propulsion system is unnecessarily complex.
Why not go all the way and use a rocket engine and call it small anti drone missile. Because even without rocket engine this is basically what it is.

If we talk 40 mm why not use a 40 mm HV Frag-Grenade with programmable fuse. These could either be launched by a 40 mm AGL or by boxed lauchers using the Metal Storm principle.

To get the smaller, cheaper end of drones under controll IMHO its paramount to use a cheap solution. Otherwise it will not be available everywhere and not in the numbers required. Therefor again in MHO guided munitions are out. To complex and to expensive. Programmable airburst or proximity fused can allready be borderline costwise but the advantage is it can be used from existing systems which just get an addition function.

That's why I was thinking MG with high ROF

graylion said:

I have been thinking further about how I'd configure an anti drone system

All of the above as per a modern SPAAG, but also an ECM system and probably a high ROF MG for the wee drones

I don't think its a viable approach to think in a single one system fits all problems way.
As with air defense drone defense needs to be layered. In fact drone defense is just air defense with additional inner layers.
So you have the theatre layer, local layer, area layer, and point defense layer.
In addition and as a difference to air defense is the possibility of striking the drone user of tactical drones.

graylion said:

but also an ECM system and probably a high ROF MG for the wee drones

I would think that an MG would only be useable in a sparsely populated area.  Otherwise you would need something that would self-destruct to avoid "friendly fire" problems.

graylion said:

That's why I was thinking MG with high ROF

Its certainly an option.
Which approach is the most effective needs to be researched. MG with high ROF can work but hitting could be such a problem that ammo consumption might be an issue. Endangering the sorounding area certainly is. Because the MG rounds will keep going. Not so much a problem for high angle fire but drones also come in low and very low. An auto tracking high ROF MG might give people headaches.
Airburst has the advantage of a more defined area of effect and danger.