GBU Guidance and Laser Designators
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Yeah, in a buddy lasing drop, only the lasing guy sees a flashing L in his TGP.
If LST is enabled then the guy doing the drop can at least see where the bomb is going to go.
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I am slightly shocked that in this day and age our systems are still so low tech, but I suppose the aircraft are fairly old.
I will be very interested in seeing the data communication options that are available on some of the up and coming modern jet fighters to see if they can address some of this.
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eh? if you’re buddy lasing you pretty much have to talk anyway. you don’t really need a complex C3 system to say “bomb 10s to impact” “laser on” “good hit”
you’re going to be saying that anyway. that’s why you have element radio.
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Paveway IIs are very simple devices. Simple is cheap, flexible, and reliable.
After a few seconds post-release the bomb seeker looks for a coded flash of light (1688 is a code number). This is very much like how a TV remote works only more narrow. After two pulse chains it confirms that it matches the code preset on the bomb. The field of view is broken up into quadrants and every 500ms evaluates what quadrant the light source is in. Based on what quadrant it blows the tail fins to steer that way. There are only four possible positions of the fins after steering is started, fully left or right (x2 fin groups). The result is it wobbles while steering. If the laser splotch is lost for a while the bomb goes dumb and can’t continue guidance.
The bomb doesn’t care where the laser energy comes from, launching airplane, another airplane, guy on the ground, etc. It would work just fine if you threw it over the side of a hot air balloon provided you pulled the arming wires and someone was pointing the IR “flashlight” at a place on the ground. The bomb either sees the target or it doesn’t which is why there are a lot of safety rules for which direction to attack from so any misses land in OK areas. Most platforms know to release the Paveway II a little long because the bomb is better able to guide short of the ballistic path than long.
This is what makes the need for laser coding in the first place. If you want to use multiple lasers and bombs in the same area you don’t want them to cross signals. The other reason is because you don’t want the enemy to produce false laser spots to ruin your aim.
In off-board lasing coordination of the laser platform with the launching platform is verbal. If you want the laser on 10 seconds before impact then when the launching platform’s computer predicts that time before impact you tell the guy over the telephone to turn on their flashlight. For ownship lasing you can do it manually or automatically. In the F-16 there is a setting that when the CCRP fall timer reaches X the laser turns on and then turns off 4 seconds after the timer reaches 0.
To ensure that the release ballistic path is near the laser spot there has to be some previous coordination to share the location. The laser designating party obviously has an acceptable target location so it is his job to make sure launching platform chucks the rock in a suitable direction so guidance will be possible. One way is to use the designation laser to produce a laser spot and have the airborne platform use a seeking sensor to see this spot and turn it into a location for CCRP delivery.
The original A-10 had such a sensor (Pave Penny) which was not a laser but could see lasers and turn it into nav or targeting data. So an old A-10A could carry and deliver a Paveway but relied on someone else to provide the laser energy for guidance. All the modern TGPs have this sort of laser discovery feature.
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Laser time is increased to 16 seconds in my config, allowing a little bit of deviation when hitting pickle button during CCRP phase of the release. Since doing so, I don’t recall a miss with an LGB.
16 seconds might not be as per doctrine, but then we don’t have to worry about jammers, etc. in F4 so I figure what the hey…
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Okay, so now I have a whole new set of questions about Buddy Lasing:
How does MY F-16 know when the bomb drop should occur if my buddy is lasing the target?
Somehow my software must be aware of the target to calculate and display the steering and targeting information on my HUD, correct?
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Basically, what happens is (supposing you lase and your wingman drops) :
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you “agree” on a target : either via description over the radio, or via a datalink-shared markpoint, or you share directly coords via the radio (not ideal)
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your wingman either create a steerpoint on the target, use the steerpoint shared via datalink, or move his cursors/TGP on the target (if possible)
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he then drops the bomb on it and let you know when the bomb is 10s to impact
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in the meantime, you have your TGP pointed at the target, ready to lase ; when he tells you, you lase.
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Boom !
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How does MY F-16 know when the bomb drop should occur if my buddy is lasing the target?
You’d drop it the same way you drop any other bomb on a target you want to hit. Designate your target (maybe using a steerpoint, or your radar, or a targeting pod) and follow the CCRP release cues until it falls off. You could also use CCIP, but typically if you have terminal guidance you want a longer fall time, and as long as it’s reasonably close to the target the guidance system will correct for small mistakes.
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Now i have a question : what happens if i release the bombs from a low altitude does it lase on release ? also sometimes i release them with no TGP lock , do they just behave like iron bomb at that point ?
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Now i have a question : what happens if i release the bombs from a low altitude does it lase on release ? also sometimes i release them with no TGP lock , do they just behave like iron bomb at that point ?
The TGP doesnt have a ‘lock’. If you release laser guided bombs with the TGP switched off, or the laser un armed, then yes, the laser guided bombs behave like dumb bombs.
If you release lower than an 8 second time of flight, then yes the TGP will lase on release.
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The TGP doesnt have a ‘lock’. If you release laser guided bombs with the TGP switched off, or the laser un armed, then yes, the laser guided bombs behave like dumb bombs.
If you release lower than an 8 second time of flight, then yes the TGP will lase on release.
I know it doesnt have a “lock” just couldnt say it better
Thanks for the answer though -
do keep in mind that the TGP does not need to be in POINT TRACK to lase. If you are in AREA TRACK it will auto lase (in fact, IRL, AREA TRACK is the required mode to be in, so that they can direct a bomb away from the target if necessary - last minute hold fire calls, a schoolbus full of kids driving past the enemy convoy, etc…).
I think (but cannot recall) that if you have not ground stabilised the TGP cursors, then it will not lase. Will have to check the manual on that one.
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Okay, so now I have a whole new set of questions about Buddy Lasing:
How does MY F-16 know when the bomb drop should occur if my buddy is lasing the target?
Somehow my software must be aware of the target to calculate and display the steering and targeting information on my HUD, correct?
Buddies pass GPS. Or use natural or man made ground structure for reference. In a earlier thread is was said that laser designators have an eye safe visible laser mode. It can be used as a laser pointer, I assume. Sounds risky if you’re are a JTAC.
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Now i have a question : what happens if i release the bombs from a low altitude does it lase on release ? also sometimes i release them with no TGP lock , do they just behave like iron bomb at that point ?
If your auto lase setting is greater than the predicted CCRP fall time then it will begin lasing immediately.
The bomb only cares about laser energy. So whether or not the TGP is in a certain mode doesn’t matter as long as the laser happens. The better question is what allows or inhibits the laser from firing. The requirements for the laser to fire are that the TGP by pointed in the no-mask zone and I think not in inertial mode (slaved). Any optical tracking mode (point/area) or zoom level is acceptable. USAF practice is to do all laser designations for Paveway bombs in AREA track at minimum zoom setting (yes even for moving targets).
An additional requirement is that the laser be visible to the Paveway seeker which looks forward. Since the bomb starts horizontal and the laser spot is usually below, the bomb cannot see the laser until it pitches down during the fall. Also there is a short 2-3s period post release that the laser guidance is suspended so it doesn’t maneuver until it’s safely separated from the airplane.
Longer lase times are more realistic than shorter. Published minimum times are in the 8-12 second range. The Falcon default of 5 is too short for reality. The only real reason to use delayed (fraction of fall time) and not continuous (entire fall time) is in situations where the bomb would suffer from flying “bee line” instead of ballistic arc or needing the extra speed for bunker penetration at impact. In most applications continuous lase is just fine.
Caper, the TGPs have 3 laser wavelengths from two laser hardware items.
~1.0 micrometer wavelength combat laser designator
~1.5 micrometer wavelength training laser designator
~0.7 micrometer wavelength infrared pointerThe designator has the switchable wavelength (shorter = higher energy photon). The pointer is a separate piece of hardware without any coded pulse or rangefinding capabilities and at a much lower power. It’s of a shorter wavelength that is suitable for being seen with NVGs.
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The only real reason to use delayed (fraction of fall time) and not continuous (entire fall time) is in situations where the bomb would suffer from flying “bee line” instead of ballistic arc or needing the extra speed for bunker penetration at impact. In most applications continuous lase is just fine.
The “bee line” could cause the bomb to fall short if the release is using a dumb bomb ballistic arc solution.
~1.0 micrometer wavelength combat laser designator
~1.5 micrometer wavelength training laser designatordo you think “training” means practice at a practice range?
or move the device in 3D. ex. Training the gun into a firing solution? Using the training laser mode for ranging. -
falcon default is 7 seconds FYI, not 5. 7 is very close to 8-12.
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It’s for training ranges or other non-combat use. You can use the training wavelength in combat for range finding and LST purposes at reduced range. I don’t think combat LGBs guide on that wavelength but I dunno. I bet there’s a LGB training round that only works with the training wavelength.
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Notice also that Falcon4 doesn’t follow reality exactly, and due to the “GBU missile characteristics” it is not always good to use very long lasing times. Once the GBU is tracking, it will beeline, but it will also fly like a missile. For this reason it is more realistic to use near default values, perhaps 7-10s.
The target exchange could be done with datalink (even IDM has ground cursor transmit) or exchanging steerpoints. I bet great majority of buddy lasing is done on preagreed targets and target areas. For possible targets of opportunity the IR pointer would probably be the way to find the target area, and then just MARK it, and lob (or whatever) bombs to the target area with the illuminator in standby.
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Training mode sounds like a pre-guidance laser.
train
/trān/
verb
gerund or present participle: training2. point or aim something, typically a gun or camera, at.
“the detective trained his gun on the side door”synonyms: aim, point, direct, level, focus; zero in
“she trained the gun on his chest”