ALR-45/50 vs other RWRs

I was reading a few threads on here about the RWR of the F-14, primarily this one: https://forums.eagle.ru/showthread.php?t=140336

As well as a reddit F-14A RIO AMA: https://www.reddit.com/r/hoggit/comments/6w6nmo/f14a_rio_ama/

And it appears that the ALR-45/50 was a very unreliable system. My question is whether such unreliability was typical of the time. Are RWRs IRL this bad? I have read briefly that the ALR-56 that initially equipped the F-15 had reliability and false alarm problems as well. I suppose we are spoiled in DCS.

Furthermore, does anyone have anymore information or actual experience with these systems? My research shows that by 1977, the ALR-45C was fitted to F-14A's (see the Standard Aircraft Characteristics sheets: http://www.alternatewars.com/SAC/F-14A_Tomcat_SAC_-_April_1977.pdf) but I cannot find any information on this version of the ALR-45.

If any one of our community F-14 crews can clarify any ways to interpret or properly find ways to use this system, I would like to know!

Thank you!

well first off the F-14 that we have in DCS currently uses the ALR-67 and yes it does have azimuth inaccuracies in it (awesome job from HB for including this). Secondly, RWR's are not that accurate to begin with, and they lie much much more than the radar does.

Indeed, the F-14B has the ALR-67, but I am mostly curious about the F-14A (as it was the one that saw most combat in the 80's).

I would like an idea as to how bad/good RWRs of the time were, and if the were actually an improvement over the Vietnam-era ones mounted in F-4's, for example.

I think someone mentioned that a RWR is never turned on at the ship or next to it, because it is such a sensible system that it just goes crazy because of that massive amount of emitters there.

I would also be strongly interested to find out how good the RWRs are in RL.

To greatly oversimplify this, from a theoretical/EE perspective most RWRs basically use time of flight detection finding using something like an adcock array antenna (yes its more complicated than that) feeding something like a crystal video receiver to limit issues with overload and because they are/were cheap. Then they process that information based on frequency/Radar PRF, signal strength and so forth to get a bearing, and possibly range to a target and an "id" and then a threat level. Based on the technology in the 60's those RWRS would be fabulously primitive to something that came a decade later and used early digital signal processing tech like the ALR-67 presumably does.

I think someone mentioned that a RWR is never turned on at the ship or next to it, because it is such a sensible system that it just goes crazy because of that massive amount of emitters there.

 

I would also be strongly interested to find out how good the RWRs are in RL.

Yeah, I'd like to see guys blow theirs out whilest on a ship if they turn it on... Its my SOP to do it even though I know its wrong... There is probably some sort of overload protection on newer ones though. As for IRL performance, maybe you can find some old engineering studies on the old stuff but at a guess most of the newer stuff is pretty sensitive/classified in terms of actual performance.

Indeed, the F-14B has the ALR-67, but I am mostly curious about the F-14A (as it was the one that saw most combat in the 80's).

 

I would like an idea as to how bad/good RWRs of the time were, and if the were actually an improvement over the Vietnam-era ones mounted in F-4's, for example.

AN/AlR45 is one of the first digital RWR systems succeeding the earlier analong AN/APR25/26 and 36 systems. its first was being introduced in 1970- 1974 meaning whilst the Vietnam war was still going on

https://www.aef.se/Avionik/Artiklar/Motmedel/Nya_hotbilder/RadarWarnStory.pdf

Sure the F15's AN/ALR56 also wasn't perfect, but that F15C in DCS had modernized version of it ( AN/ALR56M or something)

So all in all its not surprising that compared to the AN/ALR67 of the F14B it is less reliable and simpler system/

AN/AlR45 is one of the first digital RWR systems succeeding the earlier analong AN/APR25/26 and 36 systems. its first was being introduced in 1970- 1974 meaning whilst the Vietnam war was still going on

 

 

 

 

https://www.aef.se/Avionik/Artiklar/Motmedel/Nya_hotbilder/RadarWarnStory.pdf

 

Sure the F15's AN/ALR56 also wasn't perfect, but that F15C in DCS had modernized version of it ( AN/ALR56M or something)

 

So all in all its not surprising that compared to the AN/ALR67 of the F14B it is less reliable and simpler system/

Thanks for the link, I have that document saved to my HDD already :) It's a pretty good overview of the evolution of the systems.

Although the ALR-45 was entering service while the Vietnam War was going on, the US left before any of their planes fought with that system for sure. The latest Rivet Haste F-4E's had the ALR-36/37 and from the google discussions between F-4 crews and ground crew, it seemed like it was much better than the earlier systems which Robin Olds hated.

I only imagine the ALR-45/50 was better but it's hard to tell. Not a lot of info out there other than what the crew says. It seems it would be nice if many crews could paint that picture for us.

I was reading a few threads on here about the RWR of the F-14, primarily this one: https://forums.eagle.ru/showthread.php?t=140336

 

As well as a reddit F-14A RIO AMA: https://www.reddit.com/r/hoggit/comments/6w6nmo/f14a_rio_ama/

 

And it appears that the ALR-45/50 was a very unreliable system. My question is whether such unreliability was typical of the time. Are RWRs IRL this bad? I have read briefly that the ALR-56 that initially equipped the F-15 had reliability and false alarm problems as well. I suppose we are spoiled in DCS.

 

Furthermore, does anyone have anymore information or actual experience with these systems? My research shows that by 1977, the ALR-45C was fitted to F-14A's (see the Standard Aircraft Characteristics sheets: http://www.alternatewars.com/SAC/F-14A_Tomcat_SAC_-_April_1977.pdf) but I cannot find any information on this version of the ALR-45.

 

If any one of our community F-14 crews can clarify any ways to interpret or properly find ways to use this system, I would like to know!

 

Thank you!

Hi SgtPappy

I'm not so sure that the ALR-45/50 was an unreliable system, particularly for the time period in which was developed. From the reddit posts by TomcatRIO, I get the impression he was referring to the ALQ-100 rather than the ALR-45/50.:dunno:

Hi SgtPappy

 

I'm not so sure that the ALR-45/50 was an unreliable system, particularly for the time period in which was developed. From the reddit posts by TomcatRIO, I get the impression he was referring to the ALQ-100 rather than the ALR-45/50.:dunno:

He states that: "To be perfectly honest with you I do not remember the details. All i can tell you is we regularly experienced JEM, a jamming strobe on the TID created by jet engine modulation. This is what is reflected back to the AWG-9 when the radar signal hits the fan or turbine blades of the bogey aircraft engine. We did not train that much on the ECM aspects of things. The ALQ and warning systems were old and unreliable. In fact I seem to remember being instructed not to use the counter measure equipment as it acted as a homing beacon for certain SAMS. Nice huh."

There was also someone here whose father said the RWRs were useless to the point that they had to mount their own in the cockpit facing different directions.

There was also someone here whose father said the RWRs were useless to the point that they had to mount their own in the cockpit facing different directions.

https://www.upi.com/Archives/1987/04/29/Navy-using-fuzz-buster-radar-warning-devices/2670546667200/

I presume those were used because of newer SAM threats (like, newer than SA-2/3/6) showing up in the '80s?

https://www.upi.com/Archives/1987/04/29/Navy-using-fuzz-buster-radar-warning-devices/2670546667200/

 

I presume those were used because of newer SAM threats (like, newer than SA-2/3/6) showing up in the '80s?

Yep, there's a funny story about that. I know the A-6 in the early to mid 80's was equipped with an 'urgent' update to detect continuous-wave emitters (SA-6). It was a very basic detection system fitted to the glare shield. Two indicators (also fitted to the glare shield), one for the pilot and one for the B/N consisted of a set of 2 lights (green and amber), signalling whether the threat was on the plane's left or right side.

https://www.upi.com/Archives/1987/04/29/Navy-using-fuzz-buster-radar-warning-devices/2670546667200/

 

I presume those were used because of newer SAM threats (like, newer than SA-2/3/6) showing up in the '80s?

Yes, that could certainly be in an issue. And I would not blame the system or its designers for this since newer SAMs had to be programmed in and could not be as easily added to the system database as easily as I would presume it was by the time of the Gulf War.

It would still be nice to hear what other limitations/capabilities a RIO would have when concerning the RWR. Perhaps I will have to wait for the F-14A!

Yep, there's a funny story about that. I know the A-6 in the early to mid 80's was equipped with an 'urgent' update to detect continuous-wave emitters (SA-6). It was a very basic detection system fitted to the glare shield. Two indicators (also fitted to the glare shield), one for the pilot and one for the B/N consisted of a set of 2 lights (green and amber), signalling whether the threat was on the plane's left or right side.

This is how I understood it for the F-14's as well. Rudimentary indeed - which is why I have doubts about the RWR design.

https://www.upi.com/Archives/1987/04/29/Navy-using-fuzz-buster-radar-warning-devices/2670546667200/

 

I presume those were used because of newer SAM threats (like, newer than SA-2/3/6) showing up in the '80s?

you mean 70s?

Do we have any local F-14 crew members who can comment more on the RWR systems?

I wonder if the Gulf of Sidra incident F-14's could detect the MiG-23 radars.

Apologies for the late reply SgtPappy. I'll try to answer your PM in this thread if that's okay, but I don't really have much to add unfortunately.

My understanding is that the 'fuzz-buster' was specifically designed to pick up continuous wave illuminations, particularly the SA-6. The ALR-45/50 could detect the SA-2 & SA-3 etc. The ALR-45/50 was better than the ALR-25/27 and was equipped to handle an expanded frequency range (2 - 15.5 GHz). Note there are different versions of the ALR-45 (I'm sure you're well aware) and although there are similarities, I'm thinking more of the ALR-45D. The -45F was a digital/semi-digital variant prior to the advent of the ALR-67 I think.

Hi Pappy, our RWR is a very realistic recreation of the F-14s rwr and behaves somewhat different than the RWRs you might be used to from other modules (without wanting to comment on their accuracy or reliability etc). Here is a summary of how our RWR is done, which will hopefully shed a bit more light on the subject for you:

This is not necessarily in direct reply to your question anymore, but please check out this overview written by our Grover, who designed the RWR:

The procedures/logic:

- Four sensors/antennas for the radar bands of tracking radars and airborne radars.

- Each antenna FOV is ~180° (or slightly more), and almost a perfect cone.

- The sensitivity at the edges of the cone is significantly lower than in the centre.

- When we get a message from DCS about being radiated, we simulate the signal it produces in each sensor. This includes factors such as the distance from the emitter (attenuation), the angle of arrival for each antenna, noise and other random signal amplitude fluctuations.

- From this moment we treat the signal as if we didn't know about the true parameters of the emitter and we only use the information from the emulated sensors (the previous step).

- We take the amplitude of the signal from each sensor, apply signal to noise cuts, combine and reconstruct the threat direction.

- Then, the reconstructed direction together with the signal signature is compared with the list of threats already being displayed. If we find one that correlates, we update its direction. Otherwise, we create a new threat and inform about it with the 'new guy' sound.

Some consequences of the procedure described above and a bunch of other features:

- No blind spots. However, if directly above or below, the threat has to be significantly closer (compared to the horizontal plane) to pass the SNR threshold.

- The direction is reconstructed in the 2D plane (the local aircraft frame of reference). For threats significantly outside that plane, their reconstructed direction may be inaccurate, and it usually shifts towards the 12, 3, 6, or 9 o'clock from the true position.

- The direction reconstruction accuracy improves as the distance from the emitter decreases. For the scan modes of the emitter (RWS/TWS), it's somewhere around 10-15° RMS.

- For the emitters in scan modes, a misassociation of a known-threat with a new signal can happen, and it occurs quite often, especially at long ranges.

It can result in:

a) ghosts (fake threats) appearing on the display - more probable if you or the threat do some manoeuvres;

b) merging a group of two or more threats of the same type into one threat. For example, a group of two Su-27 flying in close formation, both scanning with their radars, can appear on the screen as one '29' until they get closer.

- A malfunction/damage of one antenna/sensor doesn't make you completely blind in that direction, as the two adjacent antennas should still cover that area. However, the lack of that sensor makes the direction reconstruction procedure very innacurate, and it's very likely that some threats will be displaced by more than 90°.

Compared with the default RWR from DCS:

- An entirely new dedicated code, written from the grounds up.

- Antenna/electronics emulation.

- Threat reconstruction using the emulated signals.

- Enhance information obtained from the engine with more details (radar modes, missile guidance, noise etc.).

- No blind spots.

- Imperfect like a real device should be, and not a god's eye.

a) Some weak radars can appear late.

b) The directions will be inaccurate.

c) It will be harder to estimate the number of threats of one type when they form a group.

d) You'll receive launch warnings not only when you are the target of the missile. For example when flying in a close formation with your buddy; if an enemy launches a weapon such as AIM-7 or SA-6 at your buddy, you may receive a launch warning from that threat as well.

- Detailed failures/damages.

Another thing to consider with the RWR is that the antennas move with the control surfaces, which means that this will roll your RWR picture, just as when you are maneuvering the aicraft, the RWR picture will roll with it (and might display erronous contacts). This requires additional pilot skill to take RWR readings at the proper (level) moment in the maneuver in order to keep up an accurate SA as well as an eye to spot wrong readings in between.

I hope this helps with understanding the RWR better.

This level of detail should really be done for the other modules as well. Wonder if HB have an RWR API they could share with ED.

I can tell so much about RWR from my own experience.

IRL they are pretty inaccurate copared to most DCS modules.

(thats why I love the F-14 RWR and even start to really like the Viggen RWR)

My dad said the old Torndo RWE (back in the 90's) was about +/-20, even 30 degrees.

That's only for azimuth. Not talking about showing an SA-2 where there really was an approach radar, etc.

There is pretty accurate eqipment as well though...

For the the fact that they turned off the RWR on the ships deck, totally understand that.

Metall everywhere, reflections on carrier, other A/C, loads of radio waves bouncing arround...

Hi Pappy, our RWR is a very realistic recreation of the F-14s rwr and behaves somewhat different than the RWRs you might be used to from other modules (without wanting to comment on their accuracy or reliability etc). Here is a summary of how our RWR is done, which will hopefully shed a bit more light on the subject for you:

 

This is not necessarily in direct reply to your question anymore, but please check out this overview written by our Grover, who designed the RWR:

 

The procedures/logic:

 

- Four sensors/antennas for the radar bands of tracking radars and airborne radars.

- Each antenna FOV is ~180° (or slightly more), and almost a perfect cone.

- The sensitivity at the edges of the cone is significantly lower than in the centre.

- When we get a message from DCS about being radiated, we simulate the signal it produces in each sensor. This includes factors such as the distance from the emitter (attenuation), the angle of arrival for each antenna, noise and other random signal amplitude fluctuations.

- From this moment we treat the signal as if we didn't know about the true parameters of the emitter and we only use the information from the emulated sensors (the previous step).

- We take the amplitude of the signal from each sensor, apply signal to noise cuts, combine and reconstruct the threat direction.

- Then, the reconstructed direction together with the signal signature is compared with the list of threats already being displayed. If we find one that correlates, we update its direction. Otherwise, we create a new threat and inform about it with the 'new guy' sound.

 

Some consequences of the procedure described above and a bunch of other features:

- No blind spots. However, if directly above or below, the threat has to be significantly closer (compared to the horizontal plane) to pass the SNR threshold.

- The direction is reconstructed in the 2D plane (the local aircraft frame of reference). For threats significantly outside that plane, their reconstructed direction may be inaccurate, and it usually shifts towards the 12, 3, 6, or 9 o'clock from the true position.

- The direction reconstruction accuracy improves as the distance from the emitter decreases. For the scan modes of the emitter (RWS/TWS), it's somewhere around 10-15° RMS.

- For the emitters in scan modes, a misassociation of a known-threat with a new signal can happen, and it occurs quite often, especially at long ranges.

 

It can result in:

 

a) ghosts (fake threats) appearing on the display - more probable if you or the threat do some manoeuvres;

b) merging a group of two or more threats of the same type into one threat. For example, a group of two Su-27 flying in close formation, both scanning with their radars, can appear on the screen as one '29' until they get closer.

- A malfunction/damage of one antenna/sensor doesn't make you completely blind in that direction, as the two adjacent antennas should still cover that area. However, the lack of that sensor makes the direction reconstruction procedure very innacurate, and it's very likely that some threats will be displaced by more than 90°.

 

Compared with the default RWR from DCS:

- An entirely new dedicated code, written from the grounds up.

- Antenna/electronics emulation.

- Threat reconstruction using the emulated signals.

- Enhance information obtained from the engine with more details (radar modes, missile guidance, noise etc.).

- No blind spots.

- Imperfect like a real device should be, and not a god's eye.

a) Some weak radars can appear late.

b) The directions will be inaccurate.

c) It will be harder to estimate the number of threats of one type when they form a group.

d) You'll receive launch warnings not only when you are the target of the missile. For example when flying in a close formation with your buddy; if an enemy launches a weapon such as AIM-7 or SA-6 at your buddy, you may receive a launch warning from that threat as well.

- Detailed failures/damages.

 

Another thing to consider with the RWR is that the antennas move with the control surfaces, which means that this will roll your RWR picture, just as when you are maneuvering the aicraft, the RWR picture will roll with it (and might display erronous contacts). This requires additional pilot skill to take RWR readings at the proper (level) moment in the maneuver in order to keep up an accurate SA as well as an eye to spot wrong readings in between.

 

I hope this helps with understanding the RWR better.

That's pretty impressive IronMike!:thumbup:

The early 90's (at least) version of the ALR-67, was susceptible to multiple spikes from certain, individual emitter types, is this modelled?

I know it's a daunting task, that requires a lot of man power, costs etc and Heatblur has a good relationship with Eagle Dynamics I'm sure, but I'd love it if you guys created your own simulation, it would be extraordinary! Competition isn't a bad thing.:D

Apologies for the late reply SgtPappy. I'll try to answer your PM in this thread if that's okay, but I don't really have much to add unfortunately.

 

My understanding is that the 'fuzz-buster' was specifically designed to pick up continuous wave illuminations, particularly the SA-6. The ALR-45/50 could detect the SA-2 & SA-3 etc. The ALR-45/50 was better than the ALR-25/27 and was equipped to handle an expanded frequency range (2 - 15.5 GHz). Note there are different versions of the ALR-45 (I'm sure you're well aware) and although there are similarities, I'm thinking more of the ALR-45D. The -45F was a digital/semi-digital variant prior to the advent of the ALR-67 I think.

Thanks Blaze, I figured that the -45 versions should be better than the Vietnam-era 25/27. Although I guess the issue was the high false alarm rate due to its high sensitivity which meant it was often put in a filter mode, hence the installation of fuzz-busters.

It makes me wonder how the Air Force's ALR-56 compared.

 

I hope this helps with understanding the RWR better.

IronMike - thank you very much for all this good information, and I learned a lot! I very much enjoy the more realistic setup of your F-14 RWR as it is very immersive and makes me much more careful when flying around.

Thanks Blaze, I figured that the -45 versions should be better than the Vietnam-era 25/27. Although I guess the issue was the high false alarm rate due to its high sensitivity which meant it was often put in a filter mode, hence the installation of fuzz-busters.

 

It makes me wonder how the Air Force's ALR-56 compared.

 

 

 

IronMike - thank you very much for all this good information, and I learned a lot! I very much enjoy the more realistic setup of your F-14 RWR as it is very immersive and makes me much more careful when flying around.

The 'fuzz-buster' was an expansion of the RWR capabilities. It was a simple system, only indicating left or right in the A-6, but was used in conjunction with the ALR-45/50, as it was specially designed to detect the CW waveform (SA-6), it couldn't detect the radars of the SA-2/3/4 etc.