Could The Gimbal Video Show an Atlas V Launch?

The FLIR angles are relative to ground track for horizontal and horizon for vertical

https://forums.vrsimulations.com/su..._Looking_Infrared_(FLIR)#A.2FA_FLIR_Symbology

Lookpoint Elevation Indication - The FLIR's current elevation angle in degrees relative to the horizon is displayed here. Negative values are below the horizon and positive values are above.

Lookpoint Azimuth Indication - The FLIR's lookpoint angle in degrees left or right of aircraft ground track. The numeric value is followed by the letter R or L if the azimuth is to the left or right of ground track, respectively.
 
In the gimbal video the VV is rotated but the centre crossing Flight Path/Pitch Ladder

  1. Flight Path/Pitch Ladder - The vertical flight path angle of the aircraft is indicated by velocity vector position in relation to the flight path/pitch ladder. The aircraft pitch attitude is indicated by the position of the waterline (top of the airspeed and altitude boxes) with respect to the flight path/pitch ladder. In any established flight attitude, the distance between the aircraft waterline and the velocity vector will be equal to the AoA. The aircraft roll angle is indicated by the rotation of the flight path/pitch ladder "rungs" relative to the "wings" of the velocity vector and also the bank scale. The horizon and flight path/pitch ladder lines represent the "horizon" and each 5° of angle between plus and minus 90°. Positive pitch lines are solid and are above the horizon line and negative pitch lines are dashed and are below the horizon line. For a more detailed explanation of pitch ladder behavior, see Flight Path/Pitch Ladder, below.

is not above or below the planes nose i.e. it's banking but not climbing or ascending also the altitude remains constant.

Unless i'm reading it wrong.
Uh that'll take a little time to understand. But it does not matter anyway: there is no flight path/pitch ladder shown in the ATFLIR display of the video, we have only the horizon line.
 
The FLIR angles are relative to ground track for horizontal and horizon for vertical

https://forums.vrsimulations.com/su..._Looking_Infrared_(FLIR)#A.2FA_FLIR_Symbology

Lookpoint Elevation Indication - The FLIR's current elevation angle in degrees relative to the horizon is displayed here. Negative values are below the horizon and positive values are above.

Lookpoint Azimuth Indication - The FLIR's lookpoint angle in degrees left or right of aircraft ground track. The numeric value is followed by the letter R or L if the azimuth is to the left or right of ground track, respectively.
The link you pointed to is the same link I referred to in my post #107 on the Gimbal video analysis. It's just a reference from a videogame manual to which I opposed another reference (always from a videogame to be sure, but I inserted caveats, and it definetly looks a better work (*)) which says the opposite. But in any case all this is moot (as already explained): if really the elevation of -2° is relative to the horizon then the ATFLIR is pointing to the ground and we would not be able to see the sky above the clouds in the video (barring a fish-eyed or at least a wide-angle ATFLIR, which is not the case, it was set on NAR, 1.5° x 1.5° if vrsimulation data are true (**), it would have imaged only ground at -2° elevation). I also find unbelievable that, with the aircraft moving around and changing asset (the roll angle for sure, pitch I surmise), the absolute ATFLIR elevation never ever changes from exactly -2°, while this is quite easy to explain if the -2° is relative to the airplane and the ATFLIR was just set to that fixed elevation. This is definitive I think. And notice: all this does not depends on the Atlas, it comes just from the viewing geometry of the video. The Atlas comes into play only when trying to understand where the F-18 could have been and what its absolute heading (and pitch angle) were.

(*) there's another reference I found which says the same thing I say, but given it comes from TTSA I avoided to mention it (it was also posted previously here on MB, apologies but I don't remember by whom):
1637152570687.png


(**)
The Advanced Targeting Forward Looking Infrared (ATFLIR) system provides three pilot-selectable fields of view (FOV): Wide field of view (WFOV), which is 6°x6°, medium field of view (MFOV), which is 3°x3°, and narrow field of view (NAR) which is 1.5°x1.5°.
https://forums.vrsimulations.com/support/index.php/A/G_Advanced_Targeting_FLIR_(ATFLIR)
 
Last edited:
From this thread:
https://www.metabunk.org/threads/atflir-related-manuals-technical-documents-and-resources.11801/
this file:
https://www.metabunk.org/attachments/a1-f18ac-746-100-atflir-principles-of-operation-pdf.44937/
which does not seem to be a simulation manual:
External Quote:
elevation readout display | Indicates pointing angle above or below the horizon. Negative sign is displayed when angle is below horizon.
It's the same definition as in #121 (@jarlrmai)

I guess it should read "horizontal" rather than "horizon". At 25,000 ft, the horizon is 2.81º below the horizontal.
 
From this thread:
https://www.metabunk.org/threads/atflir-related-manuals-technical-documents-and-resources.11801/
this file:
https://www.metabunk.org/attachments/a1-f18ac-746-100-atflir-principles-of-operation-pdf.44937/
which does not seem to be a simulation manual:
External Quote:
elevation readout display | Indicates pointing angle above or below the horizon. Negative sign is displayed when angle is below horizon.
It's the same definition as in #121 (@jarlrmai)

I guess it should read "horizontal" rather than "horizon". At 25,000 ft, the horizon is 2.81º below the horizontal.
I thank you, but.. don't tell me now I need to sift a page of references for a point which is, sorry to say that, obvious. How do you image the sky above the clouds with a camera pointing two degrees below the horizon and a field of view of 1.5 x 1.5 degrees? If those -2° were really relative to the horizon the Gimbal would not be an UAP, but an UUP, Unidentified Underground Phenomenon (or under water probably, in this case). And how do you keep those -2° exactly constant at that value to the tenth of a degree (I mean, a tenth of a degree) during 34 seconds of flight on an F-18, at Mach 0.58, chasing a bright IR light in the sky?
 
Last edited:
I thank you, but.. don't tell me now I need to sift a page of references for a point which is, sorry to say that, obvious. How do you image the sky above the clouds with a camera pointing two degrees below the horizon and a field of view of 1.5 x 1.5 degrees?
Being above the clouds, pointing AT the horizon ("the aparent line where earth and sky meet"), which is looking down -2 degrees from the horizontal ("plane perpendicular to the direction defined by gravity").
 
Being above the clouds, pointing AT the horizon ("the aparent line where earth and sky meet"), which is looking down -2 degrees from the horizontal ("plane perpendicular to the direction defined by gravity").
We could see cloudtops, but not the sky above them.

Try picturing yourself this situation, then go see the Gimbal video: the F-18 had a wall of clouds, with the top higher than its cruising altitude, on his left. It pointed up the nose so that the FLIR line of sight pointed left and slightly above the top of the cloud wall, where it could image the sky and track the IR light in it, possibly ~200km away, with the upper part of the very near clouds wall just below. The clouds in the Gimbal video are not horizontal, they are vertical (sub-vertical, at least) and seen from the front.
 
Last edited:
I thank you, but.. don't tell me now I need to sift a page of references for a point which is, sorry to say that, obvious. How do you image the sky above the clouds with a camera pointing two degrees below the horizon and a field of view of 1.5 x 1.5 degrees? If those -2° were really relative to the horizon the Gimbal would not be an UAP, but an UUP, Unidentified Underground Phenomenon. And how do you keep those -2° exactly constant at that value to the tenth of a degree (I mean, a tenth of a degree) during 34 seconds of flight on an F-18, at Mach 0.58, chasing a bright IR light in the sky?
A tenth of a degree? The ATFLIR display of angle is only accurate to one degree, the actual figure could probably vary between 1.51 and 2.49 or something depending on how the accurate or not the sensors are and what the developers chose to use as rounding boundaries for display.
 
A tenth of a degree? The ATFLIR display of angle is only accurate to one degree, the actual figure could probably vary between 1.51 and 2.49 or something depending on how the accurate or not the sensors are and what the developers chose to use as rounding boundaries for display.
I said a tenth of a degree only because among the many images of ATFLIR display I've seen lately some had elevation numbers such as 3.6 or 11.9 or the like, so I guess the resolution with which the ATFLIR displays the number is one tenth of a degree (whatever the internal precision of the ATFLIR may be). Sorry but I can't really remember where to find those pictures now. But even keeping the elevation steady with 1° precision in those conditions would be an astonishing feat, the 'tenth' part is really not needed anyway. And there's always the problem of imaging the sky while looking to the ground (or to the water, cloud tops, whatever).
 
Last edited:
A say a tenth of a degree only because among the many images of ATFLIR display I've seen lately some had indications such as 3.6 or 11.9 or the like, so I guess the resolution with which the ATFLIR displays the number is one tenth of a degree (whatever the internal precision of the ATFLIR may be). Sorry but I can't really remember where to find those pictures now. But even keeping the elevation steady with 1° precision in those conditions would be an astonishing feat. And there's always the problem of imaging the sky while looking to the ground (water, cloud tops, whatever).

There are various versions of ATFLIR and also similar pods that look the same/similar on display. You need to look at the actual GIMBAL video as reference (it only has 1 degree precision) though, otherwise would be saying -2.00 or whatever otherwise.

Apart from this I am not sure what you are saying? That the video is wrong about the angle? Military hardware is expensive because it's pretty good, not infallible of course. It's possible the variance from the sensor is interpolated and smoothed and corrected over time scales so a bounce between large variance is corrected for the operator.
 
There are various versions of ATFLIR and also similar pods that look the same/similar on display. You need to look at the actual GIMBAL video as reference (it only has 1 degree precision) though, otherwise would be saying -2.00 or whatever otherwise.
This may be, as it might not. The only sure thing is in the Gimbal video the number nevers changes from -2, I have no idea if it could go to -2.1 -2.2 o switch directly to -3. And this irrelevant anyway, 1° is more than enough for my argument to stand.

Apart from this I am not sure what you are saying? That the video is wrong about the angle? Military hardware is expensive because it's pretty good, not infallible of course. It's possible the variance from the sensor is interpolated and smoothed and corrected over time scales so a bounce between large variance is corrected for the operator.
No lol, not at all. I'm saying the interpretation of that angle as an absolute elevation relative to the horizon is wrong. Go read again my post #127 above please, I have edited it to add what I hope is a good explanation of what the Gimbal video imaged (and thus of what the -2° mean). In the meantime I'll try to prepare a 3D model which depicts the situation (I need to modify the clouds I used in Blender from planes to parallelepipedes to create the cloud wall, yiikesss), I hope that'll make things clear.
 
Last edited:
No lol, not at all. I'm saying the interpretation of that angle as an absolute elevation relative to the horizon is wrong. Go read again my post #127 above please, I have edited it to add what I hope is a good explanation of what the Gimbal video imaged (and thus of what the -2° mean). In the meantime I'll try to prepare a 3D model which depicts the situation (I need to modify the clouds I used in Blender from planes to parallelepipedes to create the cloud wall, yiikesss), I hope that'll make things clear.
Is your blender model of the clouds a sphere section with the same curvature as the Earth?
 
Is your blender model of the clouds a sphere section with the same curvature as the Earth?
Oh my, no. I said I assumed the Earth was flat, and why this is irrelevant to the overall geometry, and little-to-somewhat relevant to the actual numerical reults (see post scriptum at the end of post #108, I also repeated that elsewher iirc but I can't remember).

PS. Blender model with solid clouds coming soon
 
The disagreement is over whether angles show azimuth (relative to the aircraft heading) and elevation (relative to eye level), or if they show the angle at which the ATFLIR is looking down and sideways relative to its mount below the wing of the aircraft. Mauro proposes the latter.

I do not agree with Mauro, because changes in bank angle (which happen in both directions) seem not to have any effect on these numbers, and because the aircraft would need to fly at an improbable pitch to allow this type of picture.

The azimuth/elevation reading allows for the aircraft to be in level flight executing a coordinated turn, and as shown elsewherw, the numbers would be consistent with the bearing of the object (with respect to North) remaining constant, i.e. a faraway object.
 
This is the model with solid clouds (instead than bidimensional planes), I hope it does a better job in allowing to visualize the (unintuitive) geometry of the Gimbal video. Please remember that the F-18 should just be points at this scale, indeed they would fit comfortably inside the line of sights cylinders (which have a diameter of 40m in real-life units). Notice also the drawing represents only the start and end positions of the F-18: try to imagine it's describing a semicirle or something like that around the cloud (which surely was not cubical) from the two positions.

The two copies of F-18 have, in front of them, a wall of clouds, the top is ~2000m higher than the F-18 in this reconstruction (the F-18 seem higher than the clouds in the drawing below, but it's just effect of the perspective. It was the best view to show the overall geometry at glance):
1637158875457.png



This is the view from the F-18 at time=0 (I know I could try to set up a Blender camera, but I have no idea on how to do it):
1637159085711.png


The FLIR images the upper part of the vertical cloud in front and the sky above, with the Atlas ~200km away along the line of sight:
1637159343989.png




This is the view from the F-18 at time=34s
1637159218718.png


Same situation: a piece of the (vertical) cloud in front, sky above and Atlas at the end of the line of sight (there may have been clouds on the whole right side too, but the video ends here).

The angular separation between the line of sight and the top of the cloud wall is +- constant, just as in the Gimbal video, and this is not a quirk of the numbers, it's a feature of the model (see post #108).

PS.: the clouds could be higher an further away, or lower and nearer, I can't know. But very close to the airplane with respect to the Atlas. Below the F-18 there could have been more clouds, or just the clear sky, it's impossible to say just from the Gimbal video.

It's green as an Atlas, croaks as an Atlas... and then the satellite data show a wall of clouds just like that, just at the (possibily with some luck) predicted position of the F-18.. I'd say it' at least suggestive.
 
Last edited:
This introduces a 2.6⁰ error, which is bigger than the FOV of the camera.
Are you implying that the FLIR imaged even more Earth surface than the flat model implies (given this is what usually happen when you raise your elevation and then look to the horizon, you see more Earth than at sea level) or what? A drawing would help my understanding.
 
Are you implying that the FLIR imaged even more Earth surface than the flat model implies (given this is what usually happen when you raise your elevation and then look to the horizon, you see more Earth than at sea level) or what? A drawing would help my understanding.

SmartSelect_20211117-160044_Samsung Internet.jpg


There are also consequences for how the clouds appear, and where the rocket appears when it's much farther away beyond the horizon.
 

There are also consequences for how the clouds appear, and where the rocket appears when it's much farther away beyond the horizon.
The drawing alone and the cryptical sentence below could not help me, sorry. At least state clearly what you are trying to say (as I try to do, possibly failing, but at least I try), I find it hard to understand, really. What seems to me (but I may be wrong, see previous caveat) is you have the impression that if you increase your elevation, keeping your line of sight pointed steadily 2 degrees below (earth-side) the horizon, you will see a slice of sky very far away, while this does not happen on a flat Earth model. But this is not true: you are always looking 2 degrees below the horizon, wherever it is, and you see only Earth (indeed, you see more Earth surface than on the flat model, due to the curvature).

In no way you can see clouds when looking below the horizon, unless your field of view is wider than the negative declination, and then you will see more than 50% of the picture is ground, why we don't see any in the video, only clouds and sky, the Earth being flat or spherical does not matter. Then go figure resolving clouds so clearly at the far edge of your horizon, from 8300m altitude. The clouds in the video were nearby.

I would also like to remember everybody that there are two point to this discussion (about what the elevation reading of the ATFLIR display actually means):
  1. How can you image clouds and the sky above them if the center of your line of sight points to the ground (in narrow field view)?
  2. How can you keep the ATFLIR line of sight pointing steadily -2° below the horizon, with the precision of no more than 1° (and probably less, who said military hardware is expensive for a reason?), while you're chasing an IR light in the sky in an F-18 at Mach 0.58, rolling and pitching around?
 
Last edited:
can you draw a side of representation of what you think the gimbal video shows? It can be out of scale but include jet, target, earths surface, clouds. I find it really hard to match what you are saying with my own mental picture of the the gimbal setup.
 
can you draw a side of representation of what you think the gimbal video shows? It can be out of scale but include jet, target, earths surface, clouds. I find it really hard to match what you are saying with my own mental picture of the the gimbal setup.
Sure, sorry I did not think about it sooner myself. It's horrible I know, but I hope it gives the idea. The only thing missing is the Earth surface, it's 8300m below the F-18, using as scale the height of the Atlas it would be a straight horizontal line.

1637164485355.png
 
Last edited:
I've scaled down the F-18 size a bit in the Blender model so it gets easier to visualize the same scene from the model (the drawings are not at the same scale obviosuly).

1637165409801.png

There's a vertical wall of clouds in front of the F-18, it looks up and, above the edge of the wall, it sees the sky and the Atlas. Just this.
 
Last edited:
I've posted an estimate of the speed for Gimbal in the other thread, based on the time it takes to cross the FOV.
At 250 miles (~220Nm), I get a speed of ~17000 km/h. Would that be plausible for the speed of this Atlas rocket ?

Would one of you mind making a little summary here ? Does the date for Atlas rocket match Gimbal ? Does it appear to go horizontally because it's so far away that this is an effect from Earth curvature, and it's actually exiting the atmosphere ?
 
This is a little better, I just extended the clouds in front of the F-18:

1637166280840.png


Notice I have no idea of the relative distance and heights of clouds and F-18, it could have seen the clouds under any aspect, even from a glancing aspect if the height difference was not great (and then clouds are not cubic, they slope in myriad ways).
 
Last edited:
I've posted an estimate of the speed for Gimbal in the other thread, based on the time it takes to cross the FOV.
At 250 miles (~220Nm), I get a speed of ~17000 km/h. Would that be plausible for the speed of this Atlas rocket ?
It's a surely in the rocket ballpark, very high up in the atmosphere. The atlas was travelling at 2 km/s at 74.5km height, 3.3km/s at 119km when the first stage shut off. I don't know which terminal speed it reached.

Would one of you mind making a little summary here ? Does the date for Atlas rocket match Gimbal ?
As for the date, yes as far as I'm concerned, but there's a diatribe around, regarding if they meant that day or the day before (who are they? we don't know), too long to summarize here.
Does it appear to go horizontally because it's so far away that this is an effect from Earth curvature, and it's actually exiting the atmosphere ?
It appears to go horizontally because it's very far away (~200km possibly), and because the overall geometry of the encounter makes it look that way. It gained some tens km heigth while the video was taken (exact number is hard to pin down). It exited the atmosphere and it put into orbit the MUOS-3 satellite a few minutes later.
 
Last edited:
Thanks @Mauro, much appreciated. I see that the FOV I should use is 0.35 deg (not 0.7), as we are in Zoom 2 mode on the ATFLIR. With FOV=0.35 the speed is more around 9000 km/h. Maybe that's more consistent with what you would expect from a rocket at that stage of the launch.

It's certainly a strange coincidence that there was a rocket launch nearby, right about the time when Gimbal was captured.
 
About the clouds: I have looked again at the Gimbal video, if you look at it imagining the Gimbal is at the zenit, just overhead of you, you'll start 'seeing' the clouds as being vertical, as looking to the side of a well from below, this is much easier to notice when the video reverses the ATFLIR colors. It may be just me but once 'seen' it's even difficult to 'unsee', in the reversed colors part at least (I'd guess it's due to the different shading). Actually those clouds were sloped of course, surely not straight vertical, but the illusion is strong.
 
Last edited:
It's certainly a strange coincidence that there was a rocket launch nearby, right about the time when Gimbal was captured.
According to https://spaceflight101.com/2015-space-launch-statistics/ there were 20 orbital launches from Canaveral in 2015. I'll skip copy/pasting, the relevant bit us just a table that says "number if launches" and then gives the number, 20. If we pick a random two day window for the date of a UAP vid in the area, it is not hugely surprising if a launch happened during that window.

That does not include missile tests or other launches that did not achieve orbit, I have not found data on that, but possibly that would drive the likelihood of a launch in a given window up a bit.
 
According to https://spaceflight101.com/2015-space-launch-statistics/ there were 20 orbital launches from Canaveral in 2015. I'll skip copy/pasting, the relevant bit us just a table that says "number if launches" and then gives the number, 20. If we pick a random two day window for the date of a UAP vid in the area, it is not hugely surprising if a launch happened during that window.
20/year actually boils down to one every 18 days, not that calculating how much is probable that with a launch every 18 days a launch will happen in a two-day timewindow is a straightforward task, but at glance I'd say in the order of 1/9, and not knowing how you define 'hugely' I cannot say much more. The coincidence becomes a little more surprising when all the geometrical details match (roughly, of course) on the scale of hundreds of kilometers, even more surprising when you see that they also match at a scale of a few kilometers (the clouds in the video) and yet even more surprising when it later turns out those clouds are really there, roughly in the expected position and geometrical aspect, in satellite pictures.
 
Last edited:
The sky cleared on January 21st off the coast of Florida. If not further than 200km from the coast, it suggests Gimbal happened on January 20, EST. But it could be earlier in the day than the launch, as the cloud cover was present all day.
 
I'm sorry that I'm no longer involved in this fantastic technical discussion due to a busy working period. I have found many insights into what you are saying. But above all, I found another curious coincidence.
I remember that to justify the possibility that the gimbal video and the gofast video had been taken, if not by the same crew, but at least in the same operational mission, I tried to give an explanation on the call of the wind that is heard at a certain point in the video. Well, analyzing the meteorological data I found no indication of the existence of a jet stream outside Jacksonville on that exact day, but I did find one on January 24 exactly off the coast of Norfolk. This really made me think about the above hypothesis. But in the light of this new scenario I analyzed the data again and to my great surprise I found a jet stream with that intensity exactly above cape canaveral between 20 and 21 January! Probably the crew was surprised how that object remained stationary in such an intense wind field, assuming that its speed was equivalent to that of the airflow. In reality, however, one might think that the object was not stationary, but was simply flying vertically with a very low downrange. As Agatha Christie said, a coincidence is a coincidence, two coincidences are a clue, but three coincidences begin to seem like a proof ....
 
The sky cleared on January 21st off the coast of Florida. If not further than 200km from the coast, it suggests Gimbal happened on January 20, EST. But it could be earlier in the day than the launch, as the cloud cover was present all day.
Dunno what to say, from the very picture you linked there were lots of clouds over (part of) Florida and the sorrounding Atlantic on Jan 21 (see my enlargments above), and with a change in their height, as the model requires, just (roughly) where the model predicts the F-18 to be (with all the caveats which pepper my previous posts). And anyway, Jan 20 ET overlaps with Jan 21 UTC/Zulu.
 
I'll add band 2 as well (3.9 microns, the wavelength that @jplaza mentions the FLIR is tuned to in post #51. Weather satellites make use of this for 'low-level cloud and fog detection'.
13-b2.jpg
Another good resource to check the cloud cover on January 20-21 2015 : https://climatereanalyzer.org/wx/satellite/

January 21st 2015, 1:15 UTC
1637171769655.png
Good! These satellite images would indicate the presence of a consistent layer of low clouds off Florida. Probably it's Stratocumuli like these:

800wm
 
Dunno what to say, from the very picture you linked there were lots of clouds over (part of) Florida and the sorrounding Atlantic on Jan 21 (see my enlargments above), and with a change in their height, as the model requires, just (roughly) where the model predicts the F-18 to be (with all the caveats which pepper my previous posts). And anyway, Jan 20 ET overlaps with Jan 21 UTC/Zulu.
Yes I meant January 20 EST, that includes the night and early morning of January 21 UTC. But after it cleared. So it's consistent with what you're saying.
 
a field of view of 1.5 x 1.5 degrees
The field of view in Gimbal is .35° x .35°. NAR mode is 0.7°, Zoom 2 makes it half of that. A while back I used these numbers to find constraints on the object's size. I also figured out how much the size of the image increases over the duration of the clip.

You seem to be doing a lot of reinventing the wheel here. A bunch of people have worked on Gimbal. I know it's a lot, but you should review all of the Gimbal-related threads. It may wind up saving you some time, and it might inspire you to new discoveries. But IMO, it shouldn't be ignored.
 
-
The field of view in Gimbal is .35° x .35°. NAR mode is 0.7°, Zoom 2 makes it half of that. A while back I used these numbers to find constraints on the object's size. I also figured out how much the size of the image increases over the duration of the clip.

You seem to be doing a lot of reinventing the wheel here. A bunch of people have worked on Gimbal. I know it's a lot, but you should review all of the Gimbal-related threads. It may wind up saving you some time, and it might inspire you to new discoveries. But IMO, it shouldn't be ignored.
Thank you for the correction! No doubts I reinvented some wheels, but may I daresay I went a little further? I think this is a positive identification of Gimbal as certain as it can possibly be (so no more need for new discoveries here, hasta la vista Gimbal, you're Atlas V 551 - MUOS-3), given the data we have (which were not so few as originally thought after all, and I hope my putting them all together in posts #106 and #107 may be of help to someone else in case).

I would really like to hear something from @Mick West about all this, when it's convenient for him of course. In the meantime, I'm asking again if someone can be so kind to explain me how to upload files to MB, so I'll upload the Blender models and everybody can check by himself.

PS: I have read the posts you linked. The second is interesting because it says the size of the glare increased 9% during the video (I trust the work you did), while I predict the angular size remains essentialy unchanged. However we're talking about glare, not about a real image here, I think the size of the glare matters little (that's why I did not consider it at all in my work) because... it's glare, it's size has little to do with the effective size of the object producing it, indeed I bet the angular size of the Atlas at 200km is very very small, even unresolvable by the F-18 ATFLIR, if not for the glare which made it seem big. As always, I may be wrong.
 
Last edited:
I would also like to remember everybody that there are two point to this discussion (about what the elevation reading of the ATFLIR display actually means):
  1. How can you image clouds and the sky above them if the center of your line of sight points to the ground (in narrow field view)?
I hope an image is worth a thousand words:
geometry2.png

Not to scale, but mathematically accurate. Just an example, there could be many other scenarios for the cloud, like being higher just below the plane, but much shorter in length.


How can you keep the ATFLIR line of sight pointing steadily -2° below the horizon, with the precision of no more than 1° (and probably less, who said military hardware is expensive for a reason?), while you're chasing an IR light in the sky in an F-18 at Mach 0.58, rolling and pitching around?

Check some simulations in the other thread, it didn't look that difficult.

"Rolling and pitching around" is what your scenario requires. I guess it is much more challenging to simulate.
 
Back
Top