Cfrgtkky

Here is your conundrum.

The tech you are proposing is very much harder to obtain and certainly more costly than assault rifles. It also requires a lot of support infrastructure and cloud-type computing power. Backed up by lots and lots of data. Huge amounts of data, in fact. This would no longer be a rag-tag group, but a well-funded multi-level organization with a well designated hierarchical command structure, strong discipline, and a lot of training. Not quite the thing you could keep under wraps from a competent counter-intelligence unit.

Methinks that you have been reading the wrong sources for your background on Che Guevara. He was not an 'overnight wonder', but had a substantial organization and resources behind him from the get-go. He also had very good intel.

And it is that last part that is crucial. The best heads-up display technology in the world is useless if you do not have inside intel. You need info on the layout, procedures, manpower, schedule, and contingency response training.

Contrary to television, the other side are not bumbling uncoordinated incompetent idiots fumbling around, they are well trained in quickly mounting a defense.

Most of which, as I have implied, is usually hand-waved away by writers. The 'opposition' is as incompetent as is needed to advance the plot, and the protagonists have access to as many resources as necessary.

But at a minimum, I would suggest that having someone on the inside is far more valuable and viable than all of the high tech stuff you can envision. Che had his sources, and they were sympathetic and very knowledgeable.

As well, the more high tech you have, the more valuable a hacker is to you.

But remember, everything you can do, assume the enemy can and will do also.

HUDs and talking silently

Try talking without breathing out. Notice how you make no noise, but the muscles in your throat and face still move. Now imagine you have sensors stuck to the skin of your face that can track the movement of your facial muscles, tongue and throat. Wire those sensors up to a decent enough machine learning algorithm (or complex enough bespoke model) and you’ve essentially got silent Siri.

Now your guys can talk (without talking) and have the computer use their ‘voices’ to control their HUDs, deliver text messages, or even synthesise their speech in near real time to their comrades. Couple that with some ‘x is talking’ indicators and decent comm discipline and your guys can make up their operation as they go along, all in total silence.

Of course: all of the above is contingent on having solid, secure communications available over long distances, but if we’re talking dystopian cyber future then I’m sure you can say the words ‘Dark Net’, ‘WiFi Backdoor’ or ‘Mesh network’ and hand-wave that issue into oblivion.

They speak in quiet voices.

Bandits might kill everyone they encounter. Their goal is loot. You are revolutionaries. The guards are your brothers. They have families who will hate you forever if you kill their fathers and sons. These families, fathers and sons will be your people if you are successful. Talk to them. Recruit them to your side.

One of your revolutionaries is a guard also. He lets you know when there is a place that is understaffed. He lets you know who might be sympathetic to your cause. You do not attack and kill them all - you walk in and tell them it is time to rise up. You do not kill those who will not come with you. You tie them up and take them somewhere safe. They have families too. You don't want them to hate you.

Violence provokes violence. There will probably be a time for violence. Or maybe not if you play your cards right.

source

Hand Signals

Have you looked up military hand signals, not very high tech by any means but very effective. If you want to go a little further have them learn sign language. (It makes it easier to talk in detail and fits a more civilian role)

Have a Spotter that relays info

This one can be as advanced or basic as you want. Have a spotter relay enemies positions to your men, and any new developments that may arise (they can still chat to you in coms just you can’t reply). The spotter could have some sort of headset that sends enemy positions and marks them for you.

Sonic Pulse Communication

you can send detailed messages with a device that sends sonic beeps to nearby devices, much like Morse code; but it’s a very low frequency that no one can hear it. Your device will auto translate and then you can read the message.

Tactical strike forces already communicate silently using a system of hand signals. If you wanted to overcome the line-of-sight problem, couple that with something like these gloves that can interpret sign language. Signals could be relayed to teammates as text on a visor HUD or converted to speech in an earpiece. Add in a few extras like body cameras feeding data back to central command and some microphones hidden away by your inside man, and you could build a fairly silent strike force using stuff that already exists.

Silent as far as communication is concerned, that is. Avoiding sound from movement, conflicts, opening doors, etc is a completely separate problem.

Others have addressed potentially more effective ways to get weapons. In terms of technology:

**quiet communication **

To answer the question in the title:

Noise-cancelling microphones behind a balaclava or mask would allow them to use a walker-talkie fairly quietly.

A good noise-cancelling microphone should pick up a whisper against background noise. They’re improving rapidly, so that might already be possible. This would allow them to speak in a quiet whisper, which in most environments is near-silent given the background noise of traffic, air-con, etc.

A bone-conduction headset would allow them to listen to teammates without generating noise, and whilst allowing them to hear their surroundings.

HUDs and maps
HUDs are available using things like google glasses.

Maps of people’s locations are possible using radar (DIY radar and even phased arrays have been made by the tech-hacking community, using easily available parts, and for a budget around £1k.)

Passive detection of humans using Radio backsplash of WiFi signals is under development, using consumer technology.

As to how effective those would be in combat, you’ll need someone else’s experience, but from computer games, it seems pretty effective.

You don't need new tech, you actually need some rather old tech used by the military for years. Also, be mindful that as a small group, you don't have large scale battle plans to care for (Operation Barbarossa) or want to engage in lengthy firefights (static war/trench warfare). In the best case, engagements are brief and only take the shape of ambushes with the opposing side surrendering.

Communications

Coms Discipline

All communications in a battlefield need to be brief, fast and relay as much information possible while not overflooding the target with needless information. So anything out of the scope of the next engagement, direct threats or lack thereof and the main target is superfluous. You don't need to know that the enemy in the east part of town is having BBQ, you just need to know he's not in your area. Only when he comes for you, you need the information.

Hand signals

In short distance, troops coordinate with hand signals. Whole sentences are in one or two signs coupled in short gestures. "two enemies over there" is a quick gesture.

Encrypted radio, earbuds and throat microphones

If you want to go radio, make it almost silent by putting the output into an earbud and the input from a simple throat microphone like it is used by tank crews since the 80s. These setups are lightweight and low profile. Encrypting the radio is simple and makes it unuseful for the enemy to understand what you say. You have to keep radio silence when not needed though, as active radio sources can be tracked rather easily.

Maps & positional exchange

Knowing the position of an enemy might be beneficial, but if you can't see a target, you don't need to care for a target on a small scale - you can only engage what you can see as a small group. Only on a larger scale, when you plan to engage another group or on the move do strategic maps matter. During an engagement, you don't need them. Instinct and communications keep you alive.

A simple map with markers of the last known position and routes suffices to keep your senses sharp. If you want to go techier, you can take a tablet PC with maps. With some apps, one can place markers on maps that are shared. This would be really useful if it updates in a short time and again is rather low profile to acquire. Such software is often commercially available and can use GPS to mark its own position. If it is possible to make sure that the group you are fighting against does not get your markers, you can exchange these data via cellphone network or an encrypted WiFi. You do become a radio beacon this way though.

For the communication part, consider EEG to Speech, that is, electrodes on the scalp of the transmitting person, and radio/headset on the receiving person. No real speech necessary, the transmitter only imagines the speech. The speech is then encoded and transmitted to the receiver where it is decoded to speech in the headset.

https://link.springer.com/chapter/10.1007/978-3-319-10978-7_10

EEG Based Brain Computer Interface for Speech Communication:

Principles and Applications
The electrical signals in the brain, because of their fast response to cognitive processes are most suitable as non-motor controlled mediation between the human and a computer. It can serve as a communication and control channel for different applications. Though the primary goal is to restore communication in severely paralyzed population, the BCI for speech communication fetches recognition in a variety of non-medical fields, the silent speech communication, cognitive biometrics and synthetic telepathy to name a few.

And from are more advanced experiment, EEG signal to trans-cranial stimulation:
https://www.iflscience.com/brain/direct-brain-brain-communication-used-humans/

"By using advanced precision neurotechnologies including wireless EEG and robotized TMS, we were able to directly and noninvasively transmit a thought from one person to another, without them having to speak or write," Pascual-Leone continued."

In regards to realtime tracking of enemies on a HUD, I think the only "realistic" way to achieve that is to have an elite hacker/s on the insurgent's team. Accessing the enemy system to gain access to their own surveillance and relaying that data to a custom built HUD (Google Glass type hardware) is probably doable with modern technology, even if there is some manual management by the hacker. Even just camera data could feasibly be translated to rough positional data if time was spent plotting the layout of the building into 3D, setting camera locations within that map and using some kind of machine vision system to identify when a person/s was in view of a specific camera (this could probably even be managed manually if necessary). The camera system wouldn't give pinpoint realtime tracking (like a FPS game wall-hack) but would give general locations.

The latency of this system would depend on where the hacker was operating from and the path the data is taking. If it needs to be routed through a bunch of systems to cover the hacker's tracks then there may be 10s of seconds of delay in getting positional data updates. If the hacker is basically on-site or nearby somewhere the latency would be fractions of a second, but obviously more dangerous for the hacker to be traced if they are detected.

The flipside of this is that you basically need a hacker to make any of this feasible. The opponent's surveillance systems would spot the insurgents immediately without being disabled or undermined somehow, e.g. the good old pre-recorded "blank" video feed being relayed instead of the live footage of people in your base, killing your dudes.

I recently watched this movie The Girl In The Spider's Web , and in it, at the end, they made use of all the cameras already installed in the building to build a map of the entire building, there was cameras everywhere so mapping was quite easy, It required a hacker tho, but it was efficient for a sniper to take out most of the guards in the building. the sniper had a LCD scope, displaying targets like infrared.
just watch the movie, You'll see what i'm talking about.

In effect, using technology like this, with the HUD will allow our assailants to see the guards even through the walls, they know the positions of all the guards, and probably there'll be a guy on over-watch supervising the attacks, the gives orders, they follow it without having to say a word.