Thread by @PutinIsAVirus

A thread on small drones jamming and apparent lack of it in current #UkraineRussiaWar
Will simplify a lot things to give a general idea of what is going (or not going) on.
#Ukraine #russia

We have been seeing a lot of HQ videos from what appear to be commercial drones in this conflict, even being used clearly for combat purposes (as artillery spotting etc). It comes natural to ask how is this possible especially given the assumed technology of #Russia military.

First its important to isolate the 2 main, radio wave based, systems in a small drone that are most susceptible to jamming :
- GPS signal (position)
- Communications signal (control/video)

Even small commercial drones can rely on both or, according to the "mission" requirements on only one of the systems.
One can fly the drone manually relying only on direct communications (basically as a "simple" remote controlled vehicle)

One can let the drone fly itself on a predetermined path which it will it follow relying on GPS data (things are changing on this front, but its another story and not yet common practice)

Or, in ideal situations (AKA not war zones) one can use both having human intervention only in the most sensible portion of a "mission" while letting the drone fly itself for cruising, landing etc.

Another relevant thing to say is that GPS is a passive system, meaning that the drone receives radio signals from the satellite but it doesn't need to transmit them.

Communications instead are usually two ways with both the drone and its "Pilot" transmitting (hence "active") towards each other, the pilot sending the commands to the drone and the drone sending back telemetry, video etc.

The distinction between active and passive becomes fundamental in a war zone as anything actively transmitting radio signals is going to be relatively easy to locate for the enemy.

Most commercial drones rely on specific frequency ranges for communications which are very similar (if not equal in many cases) to what regular WiFi uses. This frequencies are chosen for the same reason WiFi uses them, the balance between energy requirement, range and bandwidth.

Commercial drones also developed from hardware originally intended for the RC (Remote Controlled) community, planes, cars etc. This community always had to clash with the limits of analog radio systems, and during any form of gathering radio frequencies had to be meticulously…

…managed. (Else one would control the vehicle of another one with disastrous outcomes)

The RC community was among the first to realise the potential of modern digital radio equipment when it became available as it allowed way more vehicles to be controlled at the same time in the same area and with way less hassles.

So back to jamming:

GPS is relatively very simple to jam, its based on very weak signals transmitted by satellites and its main operational concept where designed in the 80's and 90's. Jamming GPS (or GLONASS) is easy because it operates on at most 3 different frequencies which are well known.

So, transmitting a signal, more powerful than that transmitted by the GPS satellites (which is weak and distant), on the frequencies the system is based on will effectively "Jam" devices relying on it.

Military GPS is somewhat more hardened, but its not that much harder to jam (or at least at its core it isn’t, directional antennas change this but its another topic).

Communications... Here comes the interesting part,I said earlier that communications rely on similar or equal frequencies to those used by regular WiFi, or those used by other RC hobbyists.

Well, this in principle should be a problem as any wifi router could potentially "jam" your drone just as another “Pilot” could.
(there isn't only wifi operating on similar freq. to those used by comm drones, even microwave ovens, some cellphone signals etc can interfere)

This would have been a pretty big problem up to the 90s when most radio equipment was analog or almost analog

But with the advent of digital radio equipment it became relatively easy to do something that was previously almost solely employed by military equipment and extremely high end commercial one, say hello to "Frequency Hopping"

In very simple terms "Frequency hopping" means that two devices will communicate among themselves by NOT relying on a single radio frequency but rather constantly shifting them in sync.

Digital communications allow also for easy data verification (same thing going on with TCP packets for example, it is known which went lost and are re-transmitted if needed).
All this means that jamming a single frequency doesn't effect the communication.

This, in the era of analog radios (pre 2000 basically) was extremely hard to achieve, and military jamming thrived on this.

A radar would use a certain frequency ?

Cool, enemy would detect it and flood the frequency with noise making the radar signal useless (up to some extent at least). Same went for communications etc.

(continues)

Something comparable to frequency hopping was achieved manually with operators shifting frequencies when deemed needed, but it was far from ideal and analog hardware made it complex and expensive to be able to use many different frequencies.

With modern solid state radio hardware instead it is relatively easy to have a small and cheap device that can transmit and receive on a wide range of frequencies at will (and such will is defined by software).

Going back to our scenario, the war in Ukraine, militaries encounter 2 main problems when attempting to effectively jam even a small drone:

- Most of their systems are/where designed for another era.

Military industrial complex, be it US or Russian one is slow to adapt so, up to some extent, both military drones and "jamming" hardware where designed around technologies almost "old" compared to many commercial drones.

- Its technically hard… To jam a frequency you have to transmit a signal over it and to do that you have to use an amount of energy proportional to the distance you want your jamming to have affect at.

If what you have to jam can use multiple frequencies, you have to jam them all spreading the available energy across them, this is called “barrage jamming”.

Even commercial based frequency hopping (which is employed with varying degrees of quality by most commercial drones available) can shift between a wide range of frequencies, who wants to jam them has to spread the available energy across all those impacting severely the…

…effective range. (There is more to this, and modern EW, Electronic Warfare, hardware should be better at this via signal analysis but, not yet much employed especially at this scale & speed by Russia, and once more, topic for another time)

Energy is still tied to generation means, and energy production hasn't advanced so much in the last decades, especially compared to radio equipment.

So we have commercial products designed from scratch to work in what the military would call electronic contested environment, but contested by wifi routers, other drone pilots, cellphone signals and microwave ovens.

Cheap hardware and good software development have been fighting and adapting to this for by now 15 years, and as opposed to military procurement programs, in the commercial drone world, 15 years mean a dozen system iteration each an improvement over the previous one.

A good example of all this is the “first” Ukrainian war, US gave Ukraine many RQ-11 Raven recognisance drones which where military level small drones built from 2004 and on. Well, quoting Ukrainian authorities at the time, they sucked.

Russian EW equipment was able to make them completely useless. This where drones designed according antiquated (already at the time of their introduction) communication paradigms, they relied on analog radio communications with no kind of hardening against jamming.

Russian military equipment was designed to fight exactly this kind of equipment and it worked.

Ukraine had way more success employing commercial drones even then as even then, commercial products where well beyond technologically than what military would offer in this field and at this scale, or at least, most of it.

(US military has since then improved a lot, but it was a brutal cold shower).

So, all this said, commercial drones are a very valid tool in modern conflicts, jamming them isn’t easy, especially not at relevant distances.

It is relatively easy to create small “bubbles” in which all relevant frequencies will be denied, but those bubbles will be small and ineffective against hacked DJI drones flying at 1500 meters spotting tanks with their 4k cameras.

There is some modern hardware that overcomes some of this problems by using directional antennas and focusing the available energy in a single direction (anti drone rifles), but they are few, not yet much employed (especially by russia) and still of limited use even at 400…

…meters of distance.
GPS is much easier to jam, but its not fundamental for small drone operation, or at least, not for many of them.

Will close with one last point, detection.

I said earlier that anything that transmits is easy to locate by the enemy, and it is true, but given the frequencies used it is difficult for EW hardware operators to distinguish a drone pilot from a wifi router and frequency hopping makes even locating signals much harder.