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Target Designation In The Falklands

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Target Designation In The Falklands

Old 7th Aug 2021, 10:28
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See 13.05 to 14.15, there’s film of the LGB attack on the artillery piece from the forward air controller position. You can the laser designator set up as well.

I’m sure I’ve seen an extended clip which shows both this one and the earlier LGB release which is noted to have fallen short. Sorry can’t find it.

Last edited by Bagheera S; 7th Aug 2021 at 20:25.
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Old 7th Aug 2021, 12:27
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Originally Posted by Mogwi
Hi Andy,

The LRMTS was used to give the weapon aiming kit an accurate slant range, which allowed weapons to be dropped more accurately. These could be (as far as I remember) any of the weapons carried by the Harrier. The target seeker mode allowed a designated target to be highlighted in the HUD, so that the pilot could carry out the attack. I am sure that ex-fast jet will be able to give the definitive answer.

Mog
That's certainly how LRMTS worked on Jag and Tornado: as a means of cueing unguided weapons and providing an accurate range for the trigonometric calculations which generated HUD aiming symbology. The laser transmitter (designed for use at short range when directly overflying the target) was less powerful than those found in targeting pods and ground target markers, but the receiver (designed to detect faint off-board laser signals anywhere in its field of view) was much more sensitive than the "disposable" one found in Paveway guidance heads. So, as the name suggests, LRMTS was suitable for range measurement and detection of off-board targeting laser spots, but not for guiding LGBs.

Why? To aim the LRMTS at a target it was necessary to keep it in the HUD. For designating LGBs this would entail flying well behind the releasing aircraft to avoid being caught in the explosion (bearing in mind that you would quickly catch up with a LGB as it slowed down during the lofted profile) and this would mean an increased range between laser and target, compounding the effect of the low power and making the reflected signal too weak for the LGB to detect. The geometry of the target matters too; lofted LGBs come in quite flat so the laser really needs to be shining onto a vertical surface to give optimum reflectivity. That is sometimes hard to achieve with a modern targeting pod, let alone through a HUD at long range!

Last edited by Easy Street; 7th Aug 2021 at 12:49.
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Old 7th Aug 2021, 15:31
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I believe that the profile tried out was with the GR3 above the target and rolling into a steep dive at the appropriate time to designate the target (airfield), probably with the nozzles in the braking stop to reduce acceleration. Wasn’t personally involved but it was a ballsey try.

Mog
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Old 7th Aug 2021, 21:51
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Originally Posted by Easy Street
That's certainly how LRMTS worked on Jag and Tornado: as a means of cueing unguided weapons and providing an accurate range for the trigonometric calculations which generated HUD aiming symbology. The laser transmitter (designed for use at short range when directly overflying the target) was less powerful than those found in targeting pods and ground target markers, but the receiver (designed to detect faint off-board laser signals anywhere in its field of view) was much more sensitive than the "disposable" one found in Paveway guidance heads. So, as the name suggests, LRMTS was suitable for range measurement and detection of off-board targeting laser spots, but not for guiding LGBs.

Why? To aim the LRMTS at a target it was necessary to keep it in the HUD. For designating LGBs this would entail flying well behind the releasing aircraft to avoid being caught in the explosion (bearing in mind that you would quickly catch up with a LGB as it slowed down during the lofted profile) and this would mean an increased range between laser and target, compounding the effect of the low power and making the reflected signal too weak for the LGB to detect. The geometry of the target matters too; lofted LGBs come in quite flat so the laser really needs to be shining onto a vertical surface to give optimum reflectivity. That is sometimes hard to achieve with a modern targeting pod, let alone through a HUD at long range!
The document link below covers the employment of LGB's in some detail. If the LRMTS can't produce a PRF code that the Bomb can recognize. it wouldn't guide even if it could detect the reflected light (unless there was a "Guide on any L@ser light you can see" function on the guidance unit switches) and of course that the Wavelength of the IR light being produced by the L@ser ranger and the IR bandwidth of the Seeker in the bomb overlap. Jerry Pook's book covers the problems with employment of the Paveway II in the Falklands war and the main issues that stopped the weapon from being successful until the last day of the war were more a case of Duff Gen (the fact that somebody had told the 1(F) crews that LRMTS could guide a Paveway) and Duff Batteries (in the ground based designators) on the first attempts to use the weapon. I can't find my copy of Pook's book, but the first attempted mission with LGB's was on 30th May 82

https://fas.org/man/dod-101/sys/smart/jp3_09_1.pdf

https://fas.org/man/dod-101/sys/smart/jp3_09_1.pdf
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Old 7th Aug 2021, 22:53
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IIRC the laser code selector for LRMTS only controlled which code the receiver looked for when searching for an off-board laser spot; it had no effect on the code transmitted by the ranging laser, which was fixed and not typically known by the aircrew. I'd bet the duff gen was to do with that?
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Old 8th Aug 2021, 01:35
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Originally Posted by Easy Street
IIRC the laser code selector for LRMTS only controlled which code the receiver looked for when searching for an off-board laser spot; it had no effect on the code transmitted by the ranging laser, which was fixed and not typically known by the aircrew. I'd bet the duff gen was to do with that?
As stated, according Jerry Pook, 1(F) were given a brief on weapons trials with PWII in Canada just before the Argentines invaded the Falklands and the Briefing Officer had said yes to Pook's question about was it possible to use the LRMTS as an emergency designator. it was only after a couple of failed attempts, firstly by 1(F) alone and then with a single GR 3 as the designator (as it was 1(F)'s only serviceable aircraft) and the LGB's coming off a SHAR, that the Squadron got a signal saying that LRMTS and PWII guidance system were not compatible. In both cases VIFFing was used by the designator at high altitude to allow the laser to be pointed at Stanley's runway.

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Old 8th Aug 2021, 09:49
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Interesting (and ballsy, as said!). Does the book say whether the loft profile was adapted to provide a steep impact angle? I suspect that even had the codes been compatible, they might have struggled to get good guidance onto the runway with a standard loft: maximum laser reflection on a non-mirrored surface is perpendicular to that surface (regardless of where the laser is coming from) and reflected intensity falls away rapidly beyond a cone of 45 degree semi-angle from that axis. Lofted early-model Paveways came in much shallower than that and hence struggled to guide against flat horizontal surfaces like runways. From the Joint Pub you posted earlier it looks like this was well understood by 1991, so would be interesting to know if it was in 1982.

Another problem with the shallow impact angle of lofted early Paveways was weapon effects; even if it had guided you'd have to question whether the impact angle would have been sufficient for the weapon to penetrate the runway surface, rather than ricochet and detonate 'relatively' harmlessly on top. Again it would be interesting to know whether enough was known in these early days to take that into account?
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Old 8th Aug 2021, 10:57
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This thread reminded me of a previous post re. LGB's:

Harrier Falklands Conundrum
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Old 8th Aug 2021, 11:04
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Allegedly, the final targets for the PGMs were transmitted in clear and included the Argentine HQ in Stanley which hastened the surrender.. A good (non) use of the weapon!
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Old 8th Aug 2021, 11:13
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Would it have been possible to designate the G to A assets on the airfield, rather than the Vulcan/Shrike efforts?
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Old 8th Aug 2021, 12:17
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Originally Posted by Easy Street
Interesting (and ballsy, as said!). Does the book say whether the loft profile was adapted to provide a steep impact angle? I suspect that even had the codes been compatible, they might have struggled to get good guidance onto the runway with a standard loft: maximum laser reflection on a non-mirrored surface is perpendicular to that surface (regardless of where the laser is coming from) and reflected intensity falls away rapidly beyond a cone of 45 degree semi-angle from that axis. Lofted early-model Paveways came in much shallower than that and hence struggled to guide against flat horizontal surfaces like runways. From the Joint Pub you posted earlier it looks like this was well understood by 1991, so would be interesting to know if it was in 1982.

Another problem with the shallow impact angle of lofted early Paveways was weapon effects; even if it had guided you'd have to question whether the impact angle would have been sufficient for the weapon to penetrate the runway surface, rather than ricochet and detonate 'relatively' harmlessly on top. Again it would be interesting to know whether enough was known in these early days to take that into account?
According to Jerry Pook's Book, the first attack on Stanley's runway by the GR 3's were a pair doing a near vertical dive attack at slow speed from 30,000 feet with the lead being the bomber and the second doing the designation, both aircraft in full nozzle braking to keep the speed down. The SHAR mission (Flown by Clive Morrell) is not described in Pook's book, but is covered in the Falklands - The Air War publication as regards the mission flown and who flew the GR Mk 3, but not how the mission was flown. There was another attempt before that by GR Mk 3's using the same profile (high Altitude dive), but after the attempt with the SHAR, the signal came through from the UK the Self designation with LRMTS would not work.
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Old 8th Aug 2021, 12:47
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MightyGem

The ground designation for LGB attacks in the Falklands was carried out by a TACP with the Welsh Guards, under the command of Major Mike Howes, calling himself Green Dragon on the radio. Presumably your brother-in-law's colleague was part of this TACP?

The whole story of the Falklands LGB saga, (including the Navy's screwing-up of the attempted live trial in theatre), is contained in Pen and Sword's RAF Harrier Ground Attack Falklands by Jerry Pook
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Old 8th Aug 2021, 14:07
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Originally Posted by The Oberon
Would it have been possible to designate the G to A assets on the airfield, rather than the Vulcan/Shrike efforts?
The primary target of the AR Vulcan missions was to kill the TPS-43F Search Radar at Port Stanley. The Radar was located right on the edge of the town, which was one of the reasons that the plans to use the AR version of MARTEL were dropped and Shrikes were used instead (Martell had a 300lb warhead, the Shrike had a 150lb one). Dropping a 1000lb bomb that close to the town was not going to happen. The 6th Black Buck mission carried 4 Strikes, two tuned to the TPS-43 and two tuned to go after any Skyguard AAA fire control radar that locked on to the Vulcan. (the first two AR missions just carried two missiles tuned to go for the 43F,One mission was aborted and the other did light damage to the TPS-43F which was repaired within 24 hours (a Shrike detonated within 30 metres of the Antenna)). .


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Old 8th Aug 2021, 17:56
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Originally Posted by MAINJAFAD
The primary target of the AR Vulcan missions was to kill the TPS-43F Search Radar at Port Stanley. The Radar was located right on the edge of the town, which was one of the reasons that the plans to use the AR version of MARTEL were dropped and Shrikes were used instead (Martell had a 300lb warhead, the Shrike had a 150lb one). Dropping a 1000lb bomb that close to the town was not going to happen. The 6th Black Buck mission carried 4 Strikes, two tuned to the TPS-43 and two tuned to go after any Skyguard AAA fire control radar that locked on to the Vulcan. (the first two AR missions just carried two missiles tuned to go for the 43F,One mission was aborted and the other did light damage to the TPS-43F which was repaired within 24 hours (a Shrike detonated within 30 metres of the Antenna)). .
Thanks, just wondered.
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Old 8th Aug 2021, 18:43
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For What It Is Worth

I flew 3 of these sorties - one 30 May 82, and 2 on 31 May 82.

Once the LGB kits had been delivered to us, we were keen to try them as we had not had any practice with them, but there were no ground-based folk in the right place to designate for us. So it was decided to try using the GR3 LRMTS to designate. Note, in the alphabet soup of LRMTS, there is no D - so it was not designed as a designator. Our info at the time said that it might work - we found out that it didn't.

The cunning plan was for two GR3's to fly the mission. The target area for the trial was the airfield at Stanley - so no chance of collateral damage. Stanley airfield was very well defended, but there was nothing on the ground there that could reach up to touch you if you were above 20,000 ft. Apart from Day 1 and, perhaps one other occasion, to the best of my recollection there had been no missile-armed Arg aircraft over the island, so we considered the air above 20,000' - certainly above 25,000' - to be "safe".

So we flew towards the airfield in trail, at about 35,000'. The front aircraft dropped the bombs at was considered to be a reasonable spot for a ballistic trajectory to get the bombs near to the centre of the runway. I was in trail, and once the bombs had been dropped, I entered a 30 deg dive, with the nozzles in the Braking Stop to minimise acceleration, and increase time in the dive, because I needed to recover above 20,000' as I did not want to put my nose into the shark infested custard below where they could have sent something up which would have spoiled my day. I put the target symbol on the mid-point of the runway, fired the Laser Ranger, and waited for the bombs to go bang where I was aiming. They didn't. At 22,000' I had to stop and initiate recovery to stay above 20,000'.

We tried again the next day - that didn't work either. The third sortie was with a SHAR dropping the LGBs, hoping that their radar aided weapon aiming solution might be better than our wet finger in the wind and that it would work. It didn't - so we gave up and waited until we could get ground designation onto targets before using up any more of these V&A items.

We found out later that the frequency of our ranger was not sufficiently discrete to attract the seeker on the LGB.

Hope that helps.

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Old 8th Aug 2021, 19:00
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A little known event occurred one weekend when a Nimrod was flown from Kinloss to Lossiemouth where an afternoon was spent trying LGBs for size in the bomb bay. There was no information forthcoming about how they might be used, in fact I somehow doubt that it had developed that far. However it was established that the stores could be carried so I suppose it could have become an “interesting’ option.

YS
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Old 8th Aug 2021, 19:16
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Did anyone consider putting one of the portable laser designators, as successfully used by the FAC’s, on the cargo floor of a hovering helicopter? I would have thought on a clear day at 5-10kft, just outside the defended airspace, this would have given a excellent target illumination opportunity for the runway and other assets on Port Stanly airfield.
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Old 8th Aug 2021, 21:18
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Bagheera,

Two problems with that idea: jitter and grazing angle.

Jitter: airborne designators have tracking and stabilisation mechanisms to produce a steady (ish) laser spot. Ground designators don't: the laser goes exactly where the unit is pointed (it's aimed through an eyepiece). Even if you could build some kind of mounting that took out the worst of the helicopter's vibration, it would need continual manual adjustment of aim through the eyepiece to compensate for helicopter movement. At several miles' distance, even the smallest angular jitters multiply up to substantial movement of the laser spot, which reduces accuracy and runs the weapon out of energy as it continually attempts to "correct" its flightpath.

Grazing angle: ideally you need to be shining the laser at 45 degrees or less from the perpendicular to the target surface so that laser energy is reflected towards the incoming bomb and not scattered away from it. You can get away with shallower angles but performance becomes progressively less assured; the 30 degree dive described above would be marginal. To achieve a 45 degree angle from 10,000ft altitude your helicopter would only be 10,000ft horizontally from the target: definitely not safe to sit in a hover! Even reducing the grazing angle to 30 degrees it would need to be 20,000ft away: still vulnerable. The only way it could work at longer ranges would be against targets with a sloping or vertical face against which the laser could be fired, with the weapon approaching from the same direction. At longer ranges jitter would be even more of a problem, as above, and vertical target faces tend to be much smaller than horizontal ones so the chances of keeping the spot on target would be even less.

In sum, not likely to be successful.
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Old 9th Aug 2021, 05:17
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The “jitter” of a Harrier descending with full nozzle braking must have been considerable, and yet it was given a try. I understand the laser in the Harrier range finder is pointed by the pilot stick inputs. via the HUD so didn’t have the benefit of an automatic lock/track system. I would have thought this was comparable or worse than that possible from ground designator system on a hovering platform, with an operator using it in a de facto CLOS mode.

The graze angle inherent to ground designation, ie which were successfully used, would be in singular degrees. Whilst I can understand it improves with increasing angle up to 45degs, it’s clearly very effective at any angles possible from a hovering platform.

I appreciate your reply, but the question was intended for a response from a person who was close to the actual operation in 82.
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Old 9th Aug 2021, 07:14
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Originally Posted by Bagheera S
The “jitter” of a Harrier descending with full nozzle braking must have been considerable, and yet it was given a try. I understand the laser in the Harrier range finder is pointed by the pilot stick inputs. via the HUD so didn’t have the benefit of an automatic lock/track system. I would have thought this was comparable or worse than that possible from ground designator system on a hovering platform, with an operator using it in a de facto CLOS mode.
LRMTS did have a form of tracking system in that when you moved the HUD marker over a target and fired the laser, the mark would remain ground-stabilised without pilot input (the gimbal was pointed by angle and rate calculations coming from the host platform). So you could manoeuvre (or vibrate) the aircraft without the mark moving off target, so long as it remained (roughly) in the HUD field of view. Those stabilisation benefits would not be available to a ground designation unit carried in a helicopter.

The graze angle inherent to ground designation, ie which were successfully used, would be in singular degrees. Whilst I can understand it improves with increasing angle up to 45degs, it’s clearly very effective at any angles possible from a hovering platform.
Yes, and ground designation is ineffective against horizontal targets like runways, unless you can find a vantage point with suitable elevation. Vehicles and sides of buildings are typical ground (or low-level) designation targets; being small, they demand an accurate and stable aim. If the spot jitters off the top of the target, reflections can suddenly appear a *long* way beyond it and this can cause a big miss.

I appreciate your reply, but the question was intended for a response from a person who was close to the actual operation in 82.
You're welcome. Of course only someone who was there can tell you whether your idea was considered, but I thought a reply from someone with substantial experience of low- and medium-level designation of LGBs might provide useful insight into the chances of success had the idea actually been tried.

Last edited by Easy Street; 9th Aug 2021 at 07:34.
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