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Comment by Marlon1788 | Hacker News Reader

I wonder how effective this is against a microwave resistant design. microwaves are incredibly easy to deflect, 1mm sheet steel at the right angles would be interesting to see. 1M USD start up drone company inquire here.

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The drones are going to be vulnerable because they need to have some kind of antenna to communicate externally, that presumably would be pretty broadband. It would be interesting to think about how one could harden them but still allow communication ... I think it's probably possible. Something like an nmr receiver that has diodes that short it out for high power input... I have no idea if that translates practically.

something like a small hole or slit in the deflecting body would allow different wavelengths through. The microwave region extends from 1,000 to 300,000 MHz (or 30 cm to 1 mm wavelength).

Or you could use some kind of fiber optic system, worst case.

Birds can navigate in large groups just based on several birds around them. If you had a swarm that was semi-autonomous after being launched, it could avoid comms altogether.

Interesting. I wonder if there is a design that could be fully autonomous, requiring no outside connectivity.

They're called cruise missiles and have existed for decades. Putting the same avionics in a drone is just building a smaller slower cruise missile.

Also dramatically cheaper, and well within hobbiest abilities.

> because they need to have some kind of antenna to communicate externally

I mean, that's true until it isn't. Autonomous drones (otherwise known as weird looking missiles?) being used to attack a base with a fancy microwave air-defence system isn't really science fiction anymore.

I suppose cameras might be hard to shield too?

It would probably also need GPS. I think it should be possible to harden a camera. Light can go e.g. though an arbitrarily small honeycomb mesh, while microwave cant. But it might be limiting in terms of what a ln autonomous drone would need to see. Lidar might be harder

GPS is jammable, I'd assume that the base with the fancy microwave anti-air system is capable of denying it and you'd want to be capable without it anyways.

Guidance via camera has been a thing for a long time: https://en.wikipedia.org/wiki/TERCOM#DSMAC,_Digital_Scene_Ma... I don't know if it's available open source (or commercially), but I don't imagine it would take me (or any other reasonably skilled programmer) long to develop it these days. Satellite imagery is freely available from google maps if you have nothing better.

Near(ish) peer adversaries (the kind that can afford drone swarms) are definitely capable of the guidance part.

Drones can fly safely with gnss denied environments, a system we tested it was in a mine with a very narrow areas, and at a relatively high speed too, being open in the sky would be easier.

How much do the direction/location of the antenna and incoming pulse matter?

The antenna could point up and communicate with satellites. Meanwhile the pulse will be coming from underneath. Maybe it could be diffused off to the side?

A high power microwave beam will pass right through plastics and composites. Unless you add a lot of shielding, that microwave pulse can and will induct a charge in wires and electrical components. Shielding is heavy and makes a drone easier to detect.

I build drones that fly over 5G, the link os also encrypted, and use the same medium that other UEs (cellphones) use in the area, it is hard to impossible to detect even with DPI, or at least by the time you detect it, the drone would be far gone. The only vulnerable point though is the GNSS, it’s weak, prune to interference and jamming, however, there are fail safe mechanisms that if that happens then it returns or land.

Aren't we talking about physically damaging the drones with high power microwaves?

OP mentioned using a steel sheet, and how vulnerable the signal can be, while it might work for RC ones, if you use a cellular network, it won’t be much of an impact. Now of you can detect and destroy the drone on time, then yeah that works, but you will have to solve the challenge of isolating the cellular drone first from all the UEs in the area.

If you could build a drone perfectly shielded with sheet steel it would be the size of a Cessna and have the radar cross section of a B-52. The perfectly shielded drone would no longer be fit for purpose. It couldn't sneakily fly over enemy lines to spy or drop bombs or whatever. A steel sheet covered drones would just get blasted by traditional AAA.

If you can fully shield the electronics with steel then you're probably good to go. The problem is any small gap in the shielding (such as for venting heat from the rotor motors).

Even aluminum foil can do wonders here.

tin foil hat drones incoming

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