Chaff and R27(E)R

[pr1malr8ge]

MBDA meteor for one. And its there for a very important reason.

 

Ok, Rage. I havent looked into the METEOR missile system. how ever what is with you and DATALINK. you seems to always quote "important reason" as if you're privied to information that no one else can either know or possibly you think is beyond most people's ability to understand.

 

This statement is exactly why I argue with you. I'm not trying to degrade you but it just makes you come across like a complete arrogant jerk.

 

A military budget is not required to make the necessary changes. A simple change in the code will significantly improve the situation. Its been done already as user mods but of course everyone would rather fly the vanilla.

Not sure if you have ever "programmed" LOGIC like this but it's not a "SIMPLE" change in the code.

I've searched the "luas" for seeker/guidance logic. Maybe I missed it but I haven't been able to locate that. Same thing with flight model performance. The only Missile change ability that can be made from what I have found was in the missile.lua and that only lets you change thrust, detonation proximity, and 'seeker" types for each missile. There is some other options in missile.lua but it seems to be over ridden by the flight model it self. i.e. Max G time to auto destruction. How ever changing these values does not affect the missile in game as far as I can tell but I haven't fully worked on it either. The only thing affected so far is thrust. After reading Skats missile mod it might work for the drag but not sure maybe scat can futher comment on this.

I doubt Alfa is mistaking anything. He's a bit of an authority on these things:)

Probably would have been better to have worded that " I think you're mistaking"

 

He may not be, or he might be. I will still tend to agree with GG on this over Alfa's reasoning.

Edited December 10, 2015 by pr1malr8ge

[NineLine]

For all I know, they may well be experts. However, I've learnt to trust published sources rather than what my mate Dave says at the pub.

 

You are in luck, your mate Dave at the pub doesnt impact changes to DCS that I know of :)

 

It would be nice if everyone provided proof of everything they said, but thats probably not going to happen, so take everything at its source, or lack there of, but if I deleted every post on this forum that didnt establish a source, well... I'd be busy :)

[Drona]

Could anyone advise on how this inertial navigation guidance works exactly because there's a lot of bits and pieces being said about it in this thread and I'm pretty interested in how it works. My question specifically is how is the target information or co-ordinates of the target fed to the missile? Is it through GCI? Radar? or some other source?

Edited December 10, 2015 by Kunz

[GGTharos]

That math doesn't really work out for me...

Average closure for the two aircraft is 24km/m, 36km/m for the missile. Even if you crank, by the time the missile is 'out of datalink range', it's operating in terminal homing before it exits DL range.

 

 

In other words, in two minutes (the time it takes for missile impact), the distance between missile and aircraft is ~25km. It can be more with a crank, but IMHO well within SARH operation by then.

 

Anyway, I don't know, sounds interesting, RFI needed :)

 

Well according to some sources that could be the case for the R-27R - i.e. that for an R-27R launched from a MiG-29 the datalink range is some 25 km - if you compare this with published range figures for the R-27R(up to some 70 kilometers against a non-manouvering target), it would seem that the missile could outrange the datalink reach by a fairly large margin :)

[pr1malr8ge]

Could anyone advise on how this inertial navigation guidance works exactly because there's a lot of bits and pieces being said about it in this thread and I'm pretty interested in how it works. My question specifically is how is the target information or co-ordinates of the target fed to the missile? Is it through GCI? Radar? or some other source?

 

INS requires three things, a computer, accelerameters, and a gyroscope. It works off "dead reckoning" If it knows an exact starting point it can keep track of where its at. How ever it is not perfect and can err will loose accuracy over time. This is due to gyroscopic precession. Case in point back in the early days of the clinton administration a passenger flight's INS degradation caused it to fly over Russian territory and was consequently shot down. at any rate this led to GPS being aloud in the public sector. Now with "ring laser gyroscopes" the amount of degradation over time is reduces significantly but it also has "last I checked" a much more costly acquisition cost.

 

https://en.wikipedia.org/wiki/Inertial_navigation_system

 

as far as target info. It is fed to the missile before launch. It's given a point in space of where the target is along with where it should be in x amount of time and then it is fed the hosts current point in space through its ins/gps system for its computer to plot a guidance then off the rail it goes.

Edited December 10, 2015 by pr1malr8ge

[Drona]

Thanks for the info, appreciate it!

 

So the radar is not involved in launching the missile? Is that right? The radar is involved only when switching to SARH for terminal guidance?

[GGTharos]

If you need a missile datalink, the radar is involved since it transmits that information. You could launch a (Radar guided) missile initially without the radar, but that's typically the realm of SAMs, emergency procedures to get rid of the missiles from planes (because you cannot jettison them), or some seriously modern stuff (Although as a caveat, this is really about the software of the entire weapons system, and you might be able to change that programming at any time, or not - because reasons that we're not aware of).

For any playable aircraft in-game, you need the radar to launch an RF missile ... in theory, to do the following:

 

Provide initial position/programming

Tune the missile to the radar frequency (SARH only)

Generate the datalink.

 

(Of course, the physics of this process is not simulated in DCS - there's no radar frequency tuning or programming of the missile)

 

For example, launching a heat seeker won't generate a data-link, and likewise, the EOS won't generate a data-link.

Edited December 10, 2015 by GGTharos

[SDsc0rch]

ITT.......

 

[Sweep]

Thx Scorch, I lol'd.

[*Rage*]

Ok, Rage. I havent looked into the METEOR missile system. how ever what is with you and DATALINK. you seems to always quote "important reason" as if you're privied to information that no one else can either know or possibly you think is beyond most people's ability to understand.

 

Havent looked into this and couldnt find that and maybe I missed this.... Im just telling you its there. And when the engineers put it there they had a purpose in mind.

Edited December 10, 2015 by ///Rage

[red_coreSix]

Two-way data link is used in the METEOR as well as in the AIM-120D. It's mostly there to enhance the situational awareness and improve the energy efficiency of the missile trajectory since the missile can talk back to the launch platform (maybe even other aircrafts) and give updates on the status. You also obviously know when the missile went active which is always helpful.

[pr1malr8ge]

Havent looked into this and couldnt find that and maybe I missed this.... Im just telling you its there. And when the engineers put it there they had a purpose in mind.

 

Well, then if you meant it as "it's in there but I don't know why" then maybe just state it so.. I wasn't trying to really cause an issue with you.. I was merely stating how I read and react to some of your responses. you stated "it is there for an important reason". In reading this, it states you know why its there but for what ever reason you choose not to disclose this as if placing candy in front of a toddler in a clear jar that's sealed and the toddler can see it but can't obtain it. It gives the impression you're just arrogant. So please don't take this as an attack but take it as this is how I perceive you. Maybe we can get along better if we understand how we both meant our presentation of information.. Dunno. I'm taking the strides to get along maybe you can take the journey also

 

Or not what ever. Balls in your court.

[pr1malr8ge]

Two-way data link is used in the METEOR as well as in the AIM-120D. It's mostly there to enhance the situational awareness and improve the energy efficiency of the missile trajectory since the missile can talk back to the launch platform (maybe even other aircrafts) and give updates on the status. You also obviously know when the missile went active which is always helpful.

 

if the missile gave a "a I exploded message" as the detonator on the warhead goes off would be a great update in SA also. It would mean either the missile hit or atleast is no longer in flight.

 

I still say unless the Missile has a full blown INS and or GPS to give its exact position in 3d space, the missile giving feedback on "where it is" is relatively useless if it's position is not precisely where it thinks it is. Again, if this where the case if it had a full INS/GPS+2-w|Datalink it should not need a SEEKER head since the host aircraft would be able to supply fully where it should be to achieve a hit. or so this is how I view it.

[Alfa]

Yes I'm sure thats what he was refering to.. See more on topic below on your second post regarding this thats quoted

 

You said: Tharos was referring to someone elses post about being beyond DL's range. which the missile will be out of potential energy before that happens.

 

I asked: are you sure?......about the missile being out of energy before that.

 

Sorry but I have not heard of any A2A missile system that talks back not saying they are not out there but It seems a bit pointless.

 

IIRC a recent development of the the AIM-120(AIM-120D) features a two-way datalink.

 

I have searched for the last hour trying to find any referance to an internal INS system in any a2a missile platform and have yet to find any can you please point me to some references or source of this?.

 

While the missiles do have accelerometers [this can be quite small since PIZIO's are Solidstate based] the gyroscopic portion of these are not. They also require a substantial time "calibrating" even when using a Ring laser. as I stated the missile is fed with "initial" INS information from the host platform and it must compute its location with just accelerometers and time. Lacking the gyro side it is can easily be off even with mid course guidance updates for its target[once launched the host aircraft Does not GUIDE the missile it only tells the missile what the target is doing and the missile computes a new flight path with that data]. If the missile is off as I said by a few inches it can be off by 1000+ft at impact, hence the need for the SARH seeker head.

 

It seems to me that you have invented your own definition of INS and decided that this isn't present in any air-to-air missile - whereas practically every account for initial stage of flight of e.g. the AMRAAM that I have come across refers to it as being steered by its "inertial navigation system"(INS) with updates transmitted via datalink(we can call it M-link if you prefer) from "host aircraft".

 

You're mistaking M-link for two way communication between aircraft[data link].

 

Bollocks.

 

Maximum range at which the MiG-29 can provide radio correction to an in-flight R-27R missile.

[NineLine]

I think you guys need to go back and read the OP again and decide if you are discussing that, or off on a personal tangent now...

 

ITT.......

 

 

 

That's a two way street ;)

Edited December 10, 2015 by NineLine

[Alfa]

That math doesn't really work out for me...

 

What math? :D

 

Average closure for the two aircraft is 24km/m, 36km/m for the missile. Even if you crank, by the time the missile is 'out of datalink range', it's operating in terminal homing before it exits DL range.

 

In other words, in two minutes (the time it takes for missile impact), the distance between missile and aircraft is ~25km. It can be more with a crank, but IMHO well within SARH operation by then.

 

Possibly - I didn't "do the math" :) . I just thought that the 25 km support reach seemed quite short vs. claimed missile range :hmm: .

 

Anyway, I don't know, sounds interesting, RFI needed :)

 

Yeap :)

[Dudikoff]

Possibly - I didn't "do the math" :) . I just thought that the 25 km support reach seemed quite short vs. claimed missile range :hmm:

 

That's because the claimed maximum range is some theoretical case probably involving a non-maneuvering head-on bomber sized target flying fast and low, while the launching aircraft is flying very high and fast as well.

 

Any chance the 25 km reference was mentioned not as maximum MCU range, but the range till which the missile is guided by MCU on the stated maximum head on range at same altitude of 42 km?

 

Because for R-27 missiles, IIRC it's generally stated that the MCU is used for 60% of the range which would match those 25 km.

Edited December 10, 2015 by Dudikoff

[Alfa]

That's because the claimed maximum range is some theoretical case probably involving a non-maneuvering head-on bomber sized target flying fast and low, while the launching aircraft is flying very high and fast as well.

 

Any chance the 25 km reference was mentioned not as maximum MCU range, but the range till which the missile is guided by MCU on the stated maximum head on range at same altitude of 42 km?

 

Because for R-27 missiles, IIRC it's generally stated that the MCU is used for 60% of the range which would match those 25 km.

 

No there were no conditions specified - just maximum reach of radio correction between launch platform(MiG-29) and inflight missile(R-27R).

 

SARH seeker(9B1101K) acquisition range stated at some 20-25 km against RCS=5m2.

Edited December 10, 2015 by Alfa

[SDsc0rch]

That's a two way street ;)

 

 

haaaaahahaahaaa! that's really good - thx for that : )

 

(psst! gomer pyle was a MARINE!)

 

 

and........ some people actually stood watch, deployed, demonstrated the requisite knowledge to become warfare-qualified - and then worked in modeling and simulation on their shore tour and actually had a hand in verification and validation of course-of-action-analysis tools (*cough*SIMULATIONS*cough*) that modeled those systems

8)

[ShuRugal]

and........ some people actually stood watch, deployed, demonstrated the requisite knowledge to become warfare-qualified - and then worked in modeling and simulation on their shore tour and actually had a hand in verification and validation of course-of-action-analysis tools (*cough*SIMULATIONS*cough*) that modeled those systems

8)

To be fair, those people are in the minority. Most of the operators on the systems I support don't give a rat's how or why it works, they just come running to me when it stops. There are, at last check, two operators in my BN who care enough about how their systems work to learn how to do all their 10-level maintenance and be capable of describing a fault accurately enough that I don't need to spend all day troubleshooting to find it.

[pr1malr8ge]

You said: Tharos was referring to someone elses post about being beyond DL's range. which the missile will be out of potential energy before that happens.

 

I asked: are you sure?......about the missile being out of energy before that.

My apologies wasn't sure how you were referring to that line of questioning.

It was my understanding that the "M-link/datalink" or how ever you want to call it was powered/transmitted by the same POWER & Antenna as the illuminator [combined and outputted through a klystron tube]. Regardless of that fact even then which I was not even considering at the time would be the receiver[for mid course update] of the missile it self.

 

IIRC a recent development of the the AIM-120(AIM-120D) features a two-way datalink.

News to me, never looked into it. Thanks for the info

 

 

 

It seems to me that you have invented your own definition of INS and decided that this isn't present in any air-to-air missile - whereas practically every account for initial stage of flight of e.g. the AMRAAM that I have come across refers to it as being steered by its "inertial navigation system"(INS) with updates transmitted via datalink(we can call it M-link if you prefer) from "host aircraft".

No, I did not INVENT my own definition of INS. Please do go back a few posts and read what I have said when I replied to someone asking what INS is. I've never seen any reference to any mention of a gyroscope whether it be electromechanical[unlikely size weight and complexity] pizo[MEMS again unlikely as its not exactly accurate enough] or ring laser. I have how ever seen many of times the reference to the accelerometers in both technical drawings and litrature. I did how ever do more research and found listing to a IRU which is reference to INS.[all of this was in research of the aim120] While I'm probably wrong and you're most likely right. You can still do guidance with out a gyroscope and just accelerometers. it is just not accurate couple it with SARH/ARH it doesn't have to be accurate to the ft when terminal guidance is intiated. The reason I have considered this more true is the fact all INS systems require an calibration time each time it is turned on. [think of the a10c when you have to wait 4 minutes.] I could be mistaken and any time a missile is loaded on the aircraft and that aircraft is powered up it will too power up the missiles INS and sync to the aircraft's own INS system. Not sure. What I can do is actually text a IR f15 pilot and ask him specifically about this and update this when he does.

 

Bollocks.

 

Maximum range at which the MiG-29 can provide radio correction to an in-flight R-27R missile.

My apologies honestly thought you were thinking datalink for MCG was on the same system as [sorry don't know what the russian DL is call so Im just going to say] link 16. Any referance to how radio correction is transmitted on the mig29? I'm assuming the r-27r has an antenna at the rear like that of aim120 for MCG Edited December 10, 2015 by pr1malr8ge

[HellToupee]

Gyroscope is only required to calculate rotation, using accelerometers is still considered INU navigation even without gyroscope

[*Rage*]

Aaaaaaand back on topic. Any changes with todays patch? A check in missileprb will yield a probable answer but im away from home this weekend.

[Ragnarok]

Aaaaaaand back on topic. Any changes with todays patch? A check in missileprb will yield a probable answer but im away from home this weekend.

 

Nothing. I'm tired of all this and with the DCS stuff. See you in the spring, if something new. I turn to other things in my free time...

[NineLine]

Nothing. I'm tired of all this and with the DCS stuff. See you in the spring, if something new. I turn to other things in my free time...

 

Bye.