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F/A-18C current state of COMM-NAV systems on DCS


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Yesterday i was reading through the COMM-NAV systems described on "NATOPS FLIGHT MANUAL NAVY MODEL F/A-18A/B/C/D161353 AND UP AIRCRAFT" and i noticed that all practical and not technical details of this technologies are well explained and enumerated.


Knowing that, why we still have an Arma3 like systems when the documentation is there?


If DCS stands for Digital Combat Simulator then it should simulate the most important aspect on today combats: Telecommunication Systems.


No source available? Not true. You don't need to simulate the mechanisms exactly as the USN does or whatever. DCS could have a general API for all this systems. You don't even need to calculate wave propagation. Use simple propagation equations to calculate the power density of signals. Frequency switching you can program it as a simple channel switching (say you divide the spectrum in fixed frequency lengths which you number as channels and treat it as 1-2-3-etc), for the "enemy" trying to jam or intercept the signals that is getting frequency switched you can simulate a channel scanning searching for certain power level threshold (so every x seconds this algorithms checks the channel n for a power level above whatever threshold, the channel scanning can be sequential or variable). Spread Spectrum techniques can be simulated as a low power signal distributed a long many frequency channels, for "allies" that know the pseudo-random sequences used to spread the signal (im talking about DSSS) can obtain the signal easily, for the "enemies" that don't know the sequence cannot distinguish noise level from the actual signal (at long ranges from the sender and enemy listener). At closer distances or very well calibrated and sensitive enemy jammers you could use a high number of spread spectrum bands (i.e 4 spread spectrum bands that fill 5 frequency channels each) you could create a SS (Spread spectrum) channels that all transmit the same information. The jammer could jam one of the SS channels and the ally receivers only read the channels that aren't getting jammed (rake receiver).



There's also more techniques some based on the fact that the ally systems are all synchronized on a global time reference and can send information on certain time slots or with certain time characteristics.


If we already know that this techniques are on the aircraft and the details on how to select and use each of these techniques are open to the public, what prevents you from modeling it?


If it's for the technical and physical implementation don't worry about. You don't need to simulate the bits per second that a system is receiving regarding the fading of signals, doppler effect on telecom signals, multi-path reflections, directivity of antennas, electrical noise, interference between other telecom systems, etc etc. You can divide the frequency band on channels, use simple calculations of power density and propagation, use SNR (jamming signals are considered noise) levels to know if that telecom link is good ( no errors in the signal no degradation), medium (some degradation), bad (very high degradation, lose of link).


For SS the jamming system would have to jam all the SS spectrum with A LOT of power (which means that the jamming system first has detected the SS that wants to jam) to transform the link into bad state.


For SS with rake receiver the jamming system would have to jam all the SS channels involved with A LOT of power (very unlikely) to bring the link to bad condition.


For frequency switching the jamming system would have to identify the switching pattern that the aircraft is using and timming to jam the link correctly. Most of the frequency switching use a pseudo-random generator that is feed a seed number which generates a deterministic sequence (that feeds it self) of a very high length. This sequence seen as an outsider looks as if it was a random sequence (if the outsider doesn't know the seed). With this random sequence the two communicating systems can perform a know frequency switching for them, but a random switching for external viewers. This way the enemy cannot induce a deterministic sequence from listening and detecting the frecuency switching.


Above all of this with the use of the KY-58 to cipher the voice that is going to be transmitted through this links. For the Ky-58 you don't need to simulate anything only if the voice is encrypted or not.


The capability of the aircraft to act as relay would be also important. This way aircrafts can form an internal net between them without the need of external systems (i.e satellites, ground systems, AWACS, Air control, etc). Also if aircraft act as a relay between close squadrons they can transmit lower power signals which are more difficult to detect by the enemy (which could mean enemy not jamming that signal).


A lot of Anti-Jamming techniques use the links between other aircraft to communicate and transmit information data even in very high jamming conditions. Because the aircraft form a low range links between them which are very difficult to jam (require massive power, not possible) and eventually one of the aircraft nodes that has a link with the global network can transmit all the information of aircraft net. This techniques are also used in satellites for example, that are designed forming a constellation where all the satellites act as nodes and re-transmit information between them when some of the satellites has direct link connection with ground bases.



Some of the navigation systems are also capable of being transmitted through this links making TACAN and GPS navigation even in jamming environments.



I only covered the simple stuff, in the Manual I'm mentioning there's a lot of things that we don't have yet. Regarding GPS alignment, TACAN navigation and secure communication techniques that you can select on the aircraft.


I hope this brings light to aspects that need to be polished and/or worked on if you want to achieve a simulation. And regarding the jamming techniques, SS, etc. I just wanted to make you know that it's not that difficult to simulate it and that IMO it should be simulated as is the basis for aircraft that we have and yet are to come.




Probably this post will moved to whatever place and unseen, just as the last post where i pointed out that FCS system isn't well simulated acording to this Manual.


Well Anyways, Thank you for taking your time to read this :).

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4 hours ago, Hulkbust44 said:

SRS already takes care of most of the voice systems. Even MIDS and KY-58 to some extent. We would need a native DCS global radio system to rival SRS in the near future.



SRS-DCS doesn't achieve anything i mentioned and i don't think that will ever achieve it. As far as I know SRS only uses plain single channel radio links for AM and FM radios. He treats BOTH FM and AM as the same, i mean as it is implemented radio volume gets lower the far you are from the emitter, which makes some sense for AM and not so much for FM (as in FM the voice isn't modulated as amplitude so the attenuation when propagating shouldn't affect as in AM, where directly attenuating the radio signal means attenuating the voice amplitude).


It isn't simulating MIDS. MIDS as far as I understand for what stands for is a military network. Meaning talking over MIDS means converting your voice transmitting it through this link as a set of bits. So no SRS doesn't simulate MIDS because MIDS is a military network not only used to send voice but any data (targets, waypoints, AWACS calls, monitor targets, etc).




So SRS only simulates and very simpler, without any frequency switching or SS, classical AM and FM radios used ONLY for voice.


Just to make things clear KY-58 it's an analogical cipher. It's only used with FM and AM because that type of modulations re-transmit your analogical voice. 


MIDS cipher it isn't made by the KY-58. Some digital algorithm encrypts data sent through the network link. Imagine MIDS as if your PC  with WIFI was an aircraft connecting to a private network made by other PCs (aircraft, soliders pda, command control offices, etc), that's MIDS. And you send digital packets to other members of that network with your PC (aircraft), which could be audio, targets, etc.


The guy doing SRS is doing just an app to connect via VoiceIP guys playing DCS on the same server, but a bit fancy. That means that you can interactuate with this VoiceIP app (like discord for example) with your DCS buttons on the aircraft. For example (simplification) changing your AM frequency changes your APP (think like discord) voice channel to a new one.


3 hours ago, Swiftwin9s said:

What we need is for ED to implement all of the comm submenus, even if all of the actions are non functional. SRS will take up the slack.

SRS cannot create the other things (like all the stuff i talked about) it would have to duplicate all the iternal network that DCS aircraft and subsystems have to implement it. SRS it's just a VoiceIP APP like discord or TS. Not a militar telecomuncations network simulator, which it's needed to have some real life coherence with regard ECM, JAMMING, ECCM, Chiper, IFF interrogation, etc etc etc.


The implementation has to be internal, because all the aircraft systems are actually tied to this things. That's why i don't understand it isn't implemented

Edited by MrWolf
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