AGM-122 sidearm seeker question

[GGTharos]

Used up (shelf life is maybe 10 years depending on various factors, and these things are re-builds anyway) maybe, not necessarily expended. There is literally no shred of evidence of a live fire of this thing in combat anywhere that I've been able to look.

 

And the fact that they had one production run and then they were ditched apparently without being used in combat is also telling of some things. SHORAD was effective when aircraft were forced to fly into it.

 

They were used since all missiles were expended and no new ones built.

Edited March 17, 2017 by GGTharos

[jojo]

You don't need to .. that's what SEAD's all about. If they're not turning their radars on, or aren't able to keep them long enough, you're bombing stuff and there's nothing they can do about it.

 

And you can forget all these cool tactics if you have to perform a bombing run with AI in SEAD mission to cover you...the difference between RL and virtual game :music_whistling:

 

In the game posted above, when AGM-88 was fired, the SAM goes off for 2s, AGM-88 lost, SAM ON again...

Edited March 18, 2017 by jojo

[GGTharos]

That's funny :)

[Zeus67]

An you can forget all these cool tactics if you have to perform a bombing run with AI in SEAD mission to cover you...the difference between RL and virtual game :music_whistling:

 

In the game posted above, when AGM-88 was fired, the SAM goes off for 2s, AGM-88 lost, SAM ON again...

 

That's funny because unlike the Shrike the Harm can memorize the last known location of the locked emitter.

[Zeus67]

You don't need to .. that's what SEAD's all about. If they're not turning their radars on, or aren't able to keep them long enough, you're bombing stuff and there's nothing they can do about it.

 

As far as the AGM-122 goes, it's intended use seems relatively clear from old military documents:

 

"At thesmall end is the 200-pound AGM-122A Sidearm. Sidearm is actually a modified AIM-9C Sidewinder designed for short range use against such J-band threats as the ZSU-23-4"

 

AFAIK this weapon was carried but possibly never used in practice.

 

I've heard that it was used in Desert Storm by USMC Super Cobras. Anyway, the AGM-122 was not renewed because by that time the US navy was interested in the Advanced Anti-Radiation Guided Missile (AARGM). That program was also cancelled. For some time there was talk of fitting an anti-radiation seeker into Hellfire missiles but that too came to nothing.

 

Original production run for AGM-122s was for 5,000 missiles of which only 818 were built from AIM-9C stocks. There was even interest from Italy, Spain and Greece for purchase of the system.

 

The AGM-122B would have used AIM-9Ls and they would have better electronics integration including a cockpit panel for the pilot to switch seeker capabilities.

 

So in this case, like in many others, it was the better killing the good and in the end getting nothing.

 

BTW, all literature I've read says "expended" as in they were used for their intended function: killing enemy air defense radars, specially Shilkas and Geckos. How many were fired in action vs training is not specified.

[Schmidtfire]

AIM-9C was a real failure. Navy used them on F-8 Crusaders during Vietnam but they were not reliable. At that time missile reliability was not how it is today. A semi-active AIM-9C+weak radar+Vietnam weather conditions = not a very good combination. The AIM-7 Sparrows didn't perform so well either but that is a much larger missile and guided by a powerful radar.

 

Interesting around the same time Soviet produced the R-3R, semi-active Atoll (sidewinder copy). It was fielded for more than a decade, so I wonder if that missile worked better

than the AIM-9C...

[GGTharos]

I'll see what I can dig up, there are some documents that list weapon expenditures ... but generally the US* aircraft weren't going low enough for the SHORAD.

[Zeus67]

AIM-9C was a real failure. Navy used them on F-8 Crusaders during Vietnam but they were not reliable. At that time missile reliability was not how it is today. A semi-active AIM-9C+weak radar+Vietnam weather conditions = not a very good combination. The AIM-7 Sparrows didn't perform so well either but that is a much larger missile and guided by a powerful radar.

 

Interesting around the same time Soviet produced the R-3R, semi-active Atoll (sidewinder copy). It was fielded for more than a decade, so I wonder if that missile worked better

than the AIM-9C...

 

I cannot find the article but I read somewhere that the Soviets copied the AGM-122 idea by converting R-27Rs. No idea how many and if they are in use today.

 

For a long time Soviet AA doctrine was to have both versions of the same missile, IR and SARH, and to fire both at the same target. The idea was that either one or the other would hit the target.

 

It was a time when the technology was fairly new and the systems were very unreliable. Unlike today when the systems have matured and are highly reliable.

[jojo]

That's funny because unlike the Shrike the Harm can memorize the last known location of the locked emitter.

 

That's an interesting topic and i don't pretend to have definitive answer.

 

But if you try to analyze the number of HARM fired in conflicts, you start to wonder how effective is the memory mode :smilewink:

[Zeus67]

That's an interesting topic and i don't pretend to have definitive answer.

 

But if you try to analyze the number of HARM fired in conflicts, you start to wonder how effective is the memory mode :smilewink:

 

Last known location. If the set is mobile they will move it after shutting it down. Even 20 meters to one side will do the trick.

[GGTharos]

They can't move that fast. On the other hand, miss distance for HARM correlates with the distance from HARM to emitter when emitter was shut down.

 

New HARM with GPS might not care that much about this, and might not care too much about radio decoys coming on after launch, either. Depends on a lot of things though.

[Oceandar]

Yes, it will be. In fact we have a prototype defined but requires testing.

Sold :D

[sirscorpion]

Last known location. If the set is mobile they will move it after shutting it down. Even 20 meters to one side will do the trick.

 

Might work vs the old Harm, the new AGM-88E has MMWR terminal radar to detect moving objects in the last known location.

 

https://www.youtube.com/watch?v=16EimRYN3uw

[MBot]

Last known location. If the set is mobile they will move it after shutting it down. Even 20 meters to one side will do the trick.

 

I don't think mobility has anything to do regarding HARM misses. The ability to remember the target's last position is a common misconception, at least in regards to the classic HARM. It is a capability to allow the seeker to reacquire and continue the engagement, should the target turn on its radar again while the missile is still in the air. If the radar stays silent, the HARM will simply hit the ground somewhere in the vicinity of the target (the miss distance being dependent on the distance between radar and missile when the radar was turned off). The small missile seeker simply does not have the precision to determine emitter position with sufficient accuracy from a stand-off distance.

 

 

Regarding the Super Cobra and the Sidearm, this article does not make any mention of it being used during Desert Storm:

http://www.globalsecurity.org/military/library/report/1993/SJL.htm

[Schmidtfire]

Im pretty sure I heard that one tactic during the Balkans conflict was to say "Magnum!" (brevity for HARM) over radio without even shooting to make enemy SAMs shut down anyway in fear of being hit.

 

Zeus67, that R-27 anti-radiation sounds really interesting, maybe you guys should make a russian jet for your next project, hint hint ;)

[Zeus67]

I don't think mobility has anything to do regarding HARM misses. The ability to remember the target's last position is a common misconception, at least in regards to the classic HARM. It is a capability to allow the seeker to reacquire and continue the engagement, should the target turn on its radar again while the missile is still in the air. If the radar stays silent, the HARM will simply hit the ground somewhere in the vicinity of the target (the miss distance being dependent on the distance between radar and missile when the radar was turned off). The small missile seeker simply does not have the precision to determine emitter position with sufficient accuracy from a stand-off distance.

 

Fair enough. I'm learning something new. :smartass:

 

Regarding the Super Cobra and the Sidearm, this article does not make any mention of it being used during Desert Storm:

http://www.globalsecurity.org/military/library/report/1993/SJL.htm

 

I don't recall where I read that bit about Super Cobras and the Sidearm in Desert Storm. And you are right,the articles don't say when and where it was used operationally, if it was, but all of them say "expended".

[Sweep]

Im pretty sure I heard that one tactic during the Balkans conflict was to say "Magnum!" (brevity for HARM) over radio without even shooting to make enemy SAMs shut down anyway in fear of being hit.

 

That wasn't just a Balkans thing. That's a Weasel thing all around. Call Magnum on a clear frequency and watch everybody stop emitting.

 

When you call Magnum, though, maybe you should put a JDAM or SDB out his way... :)

 

Weaseling in the Harrier is going to be a lot of fun with or without Sidearms IMO...Faster and lighter A-10 FTW.

[frixon28]

Weaseling in the Harrier is going to be a lot of fun with or without Sidearms IMO...Faster and lighter A-10 FTW.

 

Wait...are you suggesting with that you have tried/used the A-10 in a designated SEAD/DEAD role? Oh my that must have been interesting

[GGTharos]

It has been done IRL - A-10s have been tasked with hunting mobile SAM radars that were trying to hide.

[Beamscanner]

Most of the following information was found via MIL-G-85742

 

AGM-122 Receiver Info:

-Made 1984

-Uses a Local Oscillator/mixer to down convert the received signals to IF

-Can detect PRF, PW and Amplitude

--This correlates to a superheterodyne Receiver--

 

-Scans between frequencies "A through G"(likely a unique band code, not referencing NATO band codes as a seeker that small wouldn't be able to track such low frequencies)

-We know it can detect an SA-8 and a ZSU-23 radar, thus we know it can at least see signals roughly between 7 and 15 GHz.

-Generates a tone for the pilot to hear that matches the signals PRF.

 

 

"WGU-15(XCL-1)/B" Seeker info:

-Conically scanned. 'Gyro speed.. between 7-20Hz'

-'Unambiguous FOV>15 degrees'

-"The system gain in each of the four quadrants" Implies a 4 quadrant array

---Of note, the seeker must be able to detect linearly polarized signals from any angle (given the missiles chance of spin), but also must be cheap given its purpose. Knowing this, the tracking technique, the rough size of the seeker, and the time of IOC, the missile likely used a small 4 spiral antenna array

---Spiral antennas are cheap, have wide bandwidths, and can see nearly all polarizations. The band width these antennas provide would indeed allow the seeker to see the SA-8 and the ZSU-23 from such a small aperture.

---Spiral antennas have wide beam widths, making for poor tracking. Though, using the sum of 4 spiral antennas can narrow your beam width and increase your tracking performance.

 

Other:

-Uses PN guidance

-"The AGM-122 was less capable than newer antiradiation missiles like the AGM-88 HARM, but also substantially cheaper, and its lighter weight enabled it to be carried by combat helicopters as well as fighter aircraft and fighter bombers."

-"While Sidearm is less capable than modern anti-radiation missiles (like AGM-88 HARM), it is still a cost-effective alternative against low-tech threats."

-"it was proposed to build new missiles as improved AGM-122B. The AGM-122B was to receive a new guidance and control system using re-programmable EEPROM memory boards."

 

--The above implies that there were some short falls with the AGM-122 guidance against modern systems. This would make sense if the missile used a conical scan tracking system like I hypothesized, as multipath effects, jammers, decoys, and amplitude modulation could cause to seeker to guide off target.

 

Based on the following

-PN guidance

-no INS unit

-no target plotting

-the use of conical scan tracking (also called 'lobe on receive')

The missile was probably very ineffective against radars with a scanning antenna. I imagine shots were only made on radars who's beams were fixated (locked) on to the launching aircraft. Reason being that the seeker would lose the radar every time the beam spun around to the other direction, in which case it might home in on a reflection off an illuminated object (think of a flashlight spinning around).

 

References:

 

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-2/page2.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-3/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-4/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-5/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742/index.html

http://www.designation-systems.net/dusrm/m-122.html

https://www.onwar.com/weapons/rocket/missiles/USA_AGM122.html

Edited March 19, 2017 by Beamscanner

[Bacab]

Most of the following information was found via MIL-G-85742

 

AGM-122 Receiver Info:

-Made 1984

-Uses a Local Oscillator/mixer to down convert the received signals to IF

-Can detect PRF, PW and Amplitude

--This correlates to a superheterodyne Receiver--

 

-Scans between frequencies "A through G"(likely a unique band code, not referencing NATO band codes as a seeker that small wouldn't be able to track such low frequencies)

-We know it can detect an SA-8 and a ZSU-23 radar, thus we know it can at least see signals roughly between 7 and 15 GHz.

-Generates a tone for the pilot to hear that matches the signals PRF.

 

 

"WGU-15(XCL-1)/B" Seeker info:

-Conically scanned. 'Gyro speed.. between 7-20Hz'

-'Unambiguous FOV>15 degrees'

-"The system gain in each of the four quadrants" Implies a 4 quadrant array

---Of note, the seeker must be able to detect linearly polarized signals from any angle (given the missiles chance of spin), but also must be cheap given its purpose. Knowing this, the tracking technique, the rough size of the seeker, and the time of IOC, the missile likely used a small 4 spiral antenna array

---Spiral antennas are cheap, have wide bandwidths, and can see nearly all polarizations. The band width these antennas provide would indeed allow the seeker to see the SA-8 and the ZSU-23 from such a small aperture.

---Spiral antennas have wide beam widths, making for poor tracking. Though, using the sum of 4 spiral antennas can narrow your beam width and increase your tracking performance.

 

Other:

-Uses PN guidance

-"The AGM-122 was less capable than newer antiradiation missiles like the AGM-88 HARM, but also substantially cheaper, and its lighter weight enabled it to be carried by combat helicopters as well as fighter aircraft and fighter bombers."

-"While Sidearm is less capable than modern anti-radiation missiles (like AGM-88 HARM), it is still a cost-effective alternative against low-tech threats."

-"it was proposed to build new missiles as improved AGM-122B. The AGM-122B was to receive a new guidance and control system using re-programmable EEPROM memory boards."

 

--The above implies that there were some short falls with the AGM-122 guidance against modern systems. This would make sense if the missile used a conical scan tracking system like I hypothesized, as multipath effects, jammers, decoys, and amplitude modulation could cause to seeker to guide off target.

 

Based on the following

-PN guidance

-no INS unit

-no target plotting

-the use of conical scan tracking (also called 'lobe on receive')

The missile was probably very ineffective against radars with a scanning antenna. I imagine shots were only made on radars who's beams were fixated (locked) on to the launching aircraft. Reason being that the seeker would lose the radar every time the beam spun around to the other direction, in which case it might home in on a reflection off an illuminated object (think of a flashlight spinning around).

 

References:

 

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-2/page2.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-3/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-4/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742-5/index.html

http://guidedmissilecomponents.emilspec.com/MIL-G-85742/index.html

http://www.designation-systems.net/dusrm/m-122.html

https://www.onwar.com/weapons/rocket/missiles/USA_AGM122.html

Thank you for those informations

[Sweep]

Wait...are you suggesting with that you have tried/used the A-10 in a designated SEAD/DEAD role? Oh my that must have been interesting

 

I have used it as such in the sim, yes. Not as hard as you think in 93% of scenarios. I wasn't really suggesting that I did that in the post, though. ;)

 

Edit: Now just imagine lofting bombs from a Harrier at some SA-15. Wouldn't that be fun!?

Edited March 21, 2017 by Sweep

[The_Tau]

I have used it as such in the sim, yes. Not as hard as you think in 93% of scenarios. I wasn't really suggesting that I did that in the post, though. ;)

 

Edit: Now just imagine lofting bombs from a Harrier at some SA-15. Wouldn't that be fun!?

 

Heh, I used friendly JTAC and BAD toss bombing in M2000C and yes. Its great fun :P

[Beamscanner]

I cannot find the article but I read somewhere that the Soviets copied the AGM-122 idea by converting R-27Rs. No idea how many and if they are in use today.

 

For a long time Soviet AA doctrine was to have both versions of the same missile, IR and SARH, and to fire both at the same target. The idea was that either one or the other would hit the target.

 

It was a time when the technology was fairly new and the systems were very unreliable. Unlike today when the systems have matured and are highly reliable.

 

R-27EP

 

http://aviationweek.com/awin/russia-details-passive-air-air-missile

[Guitrz]

Can the Sidearm be used against enemy aircraft painting you (like the R-27EP)?

Guessing not cause of the radar bands, but still?

Edited October 15, 2017 by Guitrz