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Posts mostly crossposted from my substack.

• That’s clearly not true in a general sense. Here’s a pattern that points to a different sum:

1 + 2 + 3 + … = 1 + (1 + 1) + (1 + 1 + 1) + … = 1 + 1 + 1 + … = − 12

Now the problem is this pattern leads to a contradiction because it can equally prove any number you want. So we don’t choose to use it as a definition for an infinite sum.

So you need to do a bit more work here to define what you mean here.

• In precisely the same sense that we can write 1 + 12 + 14 + … = 2, despite that no real-world process of “addition” involving infinitely many terms may be performed in a finite number of steps, we can write 1 + 2 + 3 + 4 + 5 + … = −1/​12

I think this is overstating things (which is fair enough to make the point you’re making).

The first is simply a shorthand for “the limit of this sum is 2”, which is an extremely simple, general definition, which applies in almost all contexts, and matches up with what addition means in almost all contexts. It preserves far more of the properties of addition as well—it’s commutative, associative, etc. In most cases where you want to work with the sum of an infinite series, the correct value to use for this series is 2.

The second is a shorthand for something far more complex, which applies in a far more limited range of cases, and doesn’t preserve almost any of the properties we expect of addition. It’s not linear or stable. In most cases where you want to work with sums of infinite series, the correct sum for this series is infinity. Only very rarely would you want −1/​12.

• Submission: Turing

MMAcevado simulates a Turing Machine in his mind, itself running a lossily compressed simulation of base MMAcevado. The simulated mind runs at 110,000th speed, and MMAcevado routes all IO through to the simulated mind.

• On the assumption we have self navigating drones that can detect the weakest point in a tank as soon as it gets live of site, and head straight towards it, we would presumably have developed the ability to detect such drones via cameras on the tank as soon as they have line of site.

Than all you need is a bunch of pretty weak guns on turrets mounted on the tank to shoot the drone as soon as they are detected.

Most of these pieces already exist—modern Merkavas have cameras with 360 degrees view, the software to detect a moving drone quickly from a camera is pretty trivial, hardest part is avoiding false positives, but that seems easier than navigating, software to control guns and track targets has existed for a long time.

I assume that mounting a m16 style gun on a turret with 360 by 180 degrees rotation, and sub second rotation to any position is fairly straightforward. Imagine a few of these mounted along the sides of a tank. Most of the time they’re lying flat for protection but can shoot a drone within a second of it becoming visible.

A drone moving at 70 km/​h would take 5 seconds to cover the last hundred metres to a tank, plenty of time to shoot it down.

This is mostly proven technology—it’s basically what trophy does, just we can use cheaper bullets against unarmoured drones, and use the theorised AI advances to use cheap cameras instead of more complex solutions, and the ability to distinguish enemy targets that are less obviously projectiles.

• To a mother drone located farther from the enemy at higher altitude, but not high enough to be engaged. Using laser or directional (phased array) RF.

If it has line of sight to the drones, then it has line of sight to the target, and can be engaged by them.

• I feel like the goalposts keep changing. This is not what was described in the original post.

So a few questions:

How do these drones communicate? Low on the ground P2P communications will have awful range, as will most low energy communication systems. Are they so autonomous they don’t need to communicate at all?

What’s their range? Existing drones only fly for about 20 minutes, and at a speed of about 70 km/​h. Their range is usually about 10 to 20 km. Flying low to the ground and having to navigate will imply much lower speeds, and less efficient flight, as will having to run a powerful GPU, and whatever communication system you end up using. They also have to carry a payload capable of destroying a tank. Unlike in Ukraine that requires getting past the ADS (e.g. trophy), so is going to be more sophisticated than a grenade.

Again, how are you actually destroying the tank? Firstly ADS systems are likely to be extremely effective against drones. Secondly tank armour is actually really really difficult to pierce. Drones are only effective because tanks have weak spots where it was considered to be too unlikely that an enemy could target, and it turns out that assumption was wrong. The next generation of tanks will likely not leave such weak spots, possibly by using lots of slat armour, requiring far more sophisticated—and heavier—solutions to destroy a tank using a drone.

Now for this to revolutionise warfare requires that your drone + payload can be mass produced cheaply, but everything above seriously cuts into that. You need sophisticated communication systems, battery, navigation systems, payload etc. if each unit costs 100,000 dollars instead of 1000 dollars, sending 70 to destroy 3 tanks is much less valuable a proposition.

• When is talking about kinetic energy weapons it’s referring to armour piercing sabots, because that’s what needed to pierce tank defences. I don’t know how effective ADS would be against other kinetic energy weapons because there’s never been any need to try, they’re useless against tanks. These rounds are so heavy, and fly so fast, that’s it’s practically impossible to fire them from anything weighing less than a few tons. Not relevant for a drone/​Javelin. Also notice how you’re creating epicycles upon epicycles here. A drone that fires a Javelin, that fires a railgun, to defeat an existing fairly straightforward defence. Each of those is going to be an impressive technical achievement, the entire package is going to take a while to iron out the kinks, and is going to be expensive. If drones are so powerful they’re going to completely replace existing armies, I wouldn’t expect all the epicycles.

A single javelin missile on its own costs more than an iron dome tamir interceptor, so becomes a valid target for existing SAM defences.

Sure it might be existing ADS defences aren’t enough to defend something like the phalanx, but there’s lots of implementations out there, and the trophies characteristics were chosen because it was sufficient to protect tanks. Could trophy be modified to protect more delicate equipment, or could something like the Iron Fist work? I don’t know, it’s never been tested because it’s never been necessary.

As for the drone you linked—it contains a turbojet. I cannot find any production turbojet with hundreds of kilos payload plus strong performance characteristics selling for less than a few hundred thousand dollars.

Finally I think all of this is mostly irrelevant. The phalanx consists of two parts—a relatively long range, delicate and expensive radar, and a pretty robust, shorter range, cheaper M61 Gatling gun + turret.

On a ship they’re colocated because that makes sense given limited space. But most land based SAMs separate the radar and missile launcher.

I expect that if drones ever become a serious threat will see the proliferation of lots of Gatling guns mounted on tanks and other vehicles, linked to a decentralised radar system combining lots of different radars of different specs. The radars will generally be deployed further behind the front line, (although some cheaper short range ones might be mounted on tanks) and will give targeting information to the guns scattered across the front line which will take out the drones.

The guns are much less vulnerable, and less expensive so don’t make good targets. The radars are very expensive but much further behind the front line, out of range of cheaper drones and well defended by both guns and missiles against more expensive solutions. And taking out a single radar just degrades performance, doesn’t take down the whole system.

This will be expensive and complex to develop but far quicker than your autonomous drone army, since all the pieces are already in place.

Finally you claim iron dome is out of reach of most countries, but most countries do have SAM systems of various sizes. Iron dome is unique in it’s ability to target SRBMs, and reflects the trade offs needed for that, but drones are much simpler to take down, and countries that deploy SAMs capable of taking down modern fighter jets could easily deploy ones capable of taking down drones. Tamir is just a good example since I know it’s cost and it’s not that expensive.

• Like everything you have layers of defence. Phalanx takes out all drones in an area. Against any ATGMs you use trophy or an equivalent ADS.

Also once you have a javelin/​anti armour carrying drone it’s going to set you back hundreds of thousands of dollars and be a suitable targets for iron dome style defences, which can cover a larger area and where each missile costs some 75000 dollars.

• Why compare with a Javelin, and not e.g. a Kornet which exports for 25,000 dollars (similar to a top range GPU), and can be produced for much cheaper (as evidenced by the fact Hamas is perfectly capable of producing them).

• The chances of the vision you’re espousing being viable (autonomous air based drones replacing the majority of all existing army units in the near future) is extremely low.

I think you’re looking at a war between two seconds rate armies, which have not adapted to a new technology and are suffering a large rate of attrition due to it, and assuming based on that that such a system is unbeatable.

I’m not going to go into detail about all the issues with this article, I’m just going to focus on one specific issue.

If you manage to build this entire system, how would the US respond?

With ease.

The phalanx is a gun designed to track and shoot down cruise missiles. It fires bullets at a speed more than 300 times faster than a drone. It can track this stuff incredibly accurately since it’s designed to be accurate enough to directly hit a jet powered missile moving 20 times faster than a drone. It can target at 115 degrees/​sec, and usually engages targets at 2000 yards, but has a much higher maximum range. It can fire approximately 1000 bullets before being reloaded, and has a rate of fire of 3000 bullets/​seconds.

At a distance of 1000 m a phalanx bullet takes less than a second to arrive. In that time, given costs of accelerating and decelerating, a drone could maybe get half a metre of uncertainty via jitter, at huge energy cost, something easily handled by firing 5 bullets instead of 1 (something the phalanx is already designed to handle).

The phalanx weighs about 6 tons, and has been adapted for land based use. If drones became a serious threat it could easily be mounted on tracks and provide defence for an armoured brigade over a range of a few thousand metres. It would shoot down any drone pretty much as soon as it came in range. In practice the Phalanx is probably overkill designed as it is for cruise missiles, but smaller cheaper systems could easily be developed.

The US army is not going to just obsolete all it’s existing equipment because you’ve come up with some new technology.

Also I think you’ve seriously underestimated how much these drone armies you’re trying to create will cost. Commercial drones are cheap, but not very useful once you buy an even cheaper jammer. Military grade equipment is expensive because it has high performance requirements, and is developed inefficiently for various reasons which drones don’t magically fixes. Once you add high performance P2P links, some powerful GPUs, large batteries to run these GPUs, loads of custom software running on these drones, all the infrastructure this stuff will need, etc. you’ll be looking at something no cheaper than existing weapons systems. But unlike existing weapons system which are designed to be hard to destroy, these things are basically sitting ducks. You could send a swarm of this stuff against an enemy battalion and within a few seconds a few million dollars of hardware would be shot straight out the sky.

Are bits of this valuable? Possibly. Cheap drones are likely to be used for reconnaissance, but they only have about 30 minutes of range before needing recharging, and will have to stay well away from enemy jammers, so are hardly a game changer, just another tool in the toolbox, to be used at the right times. Anti tank FPV drones? Almost certainly not long term as they’re more expensive than ATGMs, and easier to defend against using existing ADS like trophy.

And as for other stuff, like missile carrying drones. That stuff literally already exists, and is widely used. The drones are just jet engines instead of quadcopters as quadcopters have terrible range, terrible speed, terrible payload, and missiles are heavy and expensive. JDAMs are commonly used on bombs weighing 500 pounds. The Quadcopter that could carry that would be massive, slow, expensive and could be shot down by anyone with a rifle.

• Just realised I misunderstood this section of the post, going to delete, rewrite and repost.

They coordinate with missiles to defeat countermeasure such as flares and chaff from slow moving aircraft (helicopters etc) by observing and transmitting the position of the target from somewhat further away and transmitting that info to their missile.

• I think this is wildly off base.

Cheap drones are far easier to destroy than pretty much anything else on the battlefield, and are highly susceptible to electronic measures. Their only advantage is they are cheap, and current tactics and equipment hasn’t yet adapted to them. Once every vehicle contains a cheap jammer, and every unit carries them around, the cheapest drones will be far less useful (except for reconnaissance).

You suggest various countermeasures, but these end up taking us back to where we started. For example you suggested reconnaissance drones communicate via missiles. There is no way to do that for a few hundred dollars, we’re going to be talking about 10s of thousands of dollars and a much larger drone.

At that point it sucks if 50,000 dollars of reconnaissance drone is shot straight out of the sky by a cheap bullet. So you have to have some combination of armoring it, making it fly higher, giving it various countermeasures, making it fly faster, camouflaging it, etc.

Your 50,000 dollar missile carrying reconnaissance drone is also quite heavy. How long can it fly without recharging? 20 minutes? Adding more batteries barely helps because it just makes it heavier, and takes even longer to recharge. Kind of sucks to pay so much money for something which is only available 20% of the time. It’s range is also far too short for it to reach the front lines by itself. It’s going to need a mobile forward operating base with a huge battery or a generator pretty close to the front lines. Not a great place for delicate, poorly defended, expensive equipment.

All these things push you to get a petrol or diesel engine, and scale it up.

Suddenly you’re talking hundreds of thousands of dollars and have a platform not very dissimilar to ones that have existed for years.

Ok, you might say, but what if we have autonomous drones that lock onto a target from a distance, fly straight towards them, and blow them up? That won’t be vulnerable to electronic countermeasures, and so can stay cheap.

• I’m interested in how much processing time Waymo requires. I.e. if I sped up the clock speed in a simulation such that things were happening much faster, how fast could we do that and still have it successfully handled the environment?

It’s arguably a superhuman driver in some domains already (fewer accidents), but not in others (handling OOD road conditions).

• Reminds me of the risk from mirror organisms. Basically you create cyanobacteria using right handed amino acids instead of left handed ones, and it outcompetes everything else because nothing can predate it (it’s indigestible to normal organisms).

# Is it jus­tifi­able for non-ex­perts to have strong opinions about Gaza?

8 Jan 2024 17:31 UTC
23 points