"Evolving" transitory tech: FPV drones & electronic warfare

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Back in the 1930's the Nazi government of Germany sent troops and vehicles to assist Franco's Nationalist-Fascist coup (later civil war) effort in Spain.

The only tanks available for employment (testing) in Spain were Pzkpfw I, bulletproof tankettes with two normal calibre machineguns. They did of course encounter bulletproofed vehicles of Soviet manufacture and even their steel core bullets proved to be useless against those. Germany got ahead of that problem by using 20 mm autocannons in the successor and later 37 mm cannons (and 75 mm stub guns) in the last pre-WW2 tank models.

The tech that was employed in Spain was hinting at the future, but it wasn't the future. Most of it was outdated two years later already.

I suppose the "This is the future of war!" claims based on what's happening in Ukraine will prove to be just as durable.

Let's look at a most striking example; the FPV (first person view) remote-controlled kamikaze quadcopter with a 1980's shaped charge that's a terrible threat to almost any tank in existence today. These proved to be more practical than Nammo's experiment with a multicopter that has a downwards-firing bazooka. For all I know (unconfirmed info) the rule of thumb is that you need ten of these for one hit, and in regard to anti-tank warfare they are very often employed against already immobilised or even abandoned tanks. Success story videos on Youtube have a "survivor bias".

These remote-controlled drones need a radio line of sight to transmit the steering commands and much more bandwidth to transmit a video feed from the drone to the operator. The onboard radio is tiny and weak and has no directional antenna. An airborne larger drone could jam this signal easily, but the ground forces under attack lacked a line of sight to the operator's radio and were thus hardly able to jam the video feed.

You can observe that the video feed of such kamikaze drone attacks often interrupts briefly before impact. All early such videos had this degradation and eventual loss of the video feed (example).

 

At that time the self-defending ground forces were able to employ a jammer to jam the steering command transmissions, for the attacking drone was in the defender's field of view. Two approaches were used; directional jamming with a directional antenna (examples) and semi-spherical/omnidirectional jamming (example). The latter was usually automated, while the former usually took the shape of a jamming 'rifle' pointed at the drone. The directional approach transmits more energy into the drone's antenna, which allows for a longer range (or weaker emitter). The omnidirectional approach did not require knowledge about the drone's whereabouts; a detection of the video feed signal would trigger a jamming of the steering commands datalink.

The jammed frequencies were often the typical frequencies used by commercial DJI drones; 2.4 GHz and 5.8 GHz. Some jammers were only built to jam the older 2.4 GHz range (jamming up to 3 GHz) and were useless against 5.8 GHz signals, leading some people to conclude that the self-protection jammers seen on tanks a second before impact of the kamikaze drone were useless. Predictably, there was and is a race of measures and countermeasures in Ukraine; different frequencies are now used (2.4 and 5.8 GHz are widely considered useless by now due to the jamming), often as modification of commercial drones by tinkerers.

The attackers attempted to solve the connection loss issue by using high vantage points or a radio repeater on a bigger drone. Nowadays many attack videos don't show the typical degradation and loss of the video feed any more.

The defending ground force have a line of sight to the repeater as well, so jamming the video feed (downlink) rather than mostly the steering signal (uplink) is feasible if an airborne repeater is used that has the attack target in line of sight. In fact, the defenders might triangulate the repeater (or detect it by radar) and jam it directly (with directional antenna and strong jammer) in an area defence effort rather than to rely on a short range omnidirectional self-protection jammers on vehicles, at trenches or in backpacks.

The self-protection jammers can be valuable, of course. A self-protection jammer can jam the drone if it's ahead of it in the measures-countermeasures race. The defenders' problem is that this doesn't necessarily help. A drone can be independent of its radio link entirely in the final attack phase; it can be "locked-on" the target at a safe distance (safe from omnidirectional self-protection jammers) and then execute its terminal approach to hit. this is 1970's technology, already seen in the AGM-65A "Maverick" missile. It's not much of a challenge for an average young electrical engineer or a programmer, as the pattern recognition algorithms are easily available. You just need a bit more computing power in the drone than for normal flying and you need to crack DJI's proprietary steering software if you want to use DJI drones.

Maybe the radio jamming efforts will escalate to the point that all drones above treetop altitude will be detected and submitted to strong directional RF jamming efforts. Maybe the entire battlefield will be jammed broadband by so many cheap & small emitters that you cannot triangulate and kill them by artillery.

That will still not protect from drones, as aforementioned pattern recognition tech long since advanced to the point that drones could find, identify, decide to attack and attack ground targets on their own, without any radio link. And maybe they even do so from multiple directions, with a couple of linked drones splitting up after 'locking on' themselves. Or they communicate by means that would not be jammed as long as they fly in a very close formation (acoustic, by light or by radio frequencies with very high atmospheric attenuation).

Maybe you think a typical hard kill active protection system for tanks would protect against drones? It might, but such systems could easily be saturated by an attack of more than six drones within few seconds and they usually only intercept the incoming munition at a few metres distance. Hard kill APS were designed with anti-tank guided missiles and RPGs in mind. An anti-ATGM solution from the 1980's combined a radar with machineguns to shoot down the missile. Almost all other systems are meant to be able to stop a RPG shot at very short distances, and thus their intercept of the munition is at very short distances.

That's a problem, for an airborne drone does not need to come close to hit, penetrate and potentially destroy a tank. The evidence for this is the smart artillery munition that fires with EFP warheads at tanks. You can easily see the distance involved.

A drone could calculate a distance estimation based on how quickly the target becomes bigger in the vide (knowing the own speed by inertial sensor) and fuse a EFP for lethal effect from a safe distance without any potentially jammable rangefinding procedure.

So what next? Dazzle the drone with laser? It might not even use an optical sensor. Maybe burn or perforate the drone with a laser or gun?

 

I wrote about autonomous attack drones years ago (of course no original thought of mine). I wrote about the remotely controlled weapon station for anti-drone defence (with possibly a little utility against ATGMs as well) years ago. I also wrote about the hard kill APS with RPG and ATGM in mind years ago. These two hard kill defences were very obvious choices to me, but are just barely in existence outside of Israel.

All that electronic warfare with jamming and radio wizardry to counter jamming are extremely important right now, but they are not the "future of land warfare". There will be jamming, but you will need hard kill defences. The electronic warfare defences of Ukraine 2022 and 2023 will look like a T-26's merely bulletproof armour in 1941; of little use, and definitely not the future.

S O

defence_and_freedom@gmx.de

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