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Re: Of DAS, EOTS etc..

Unread postPosted: 14 Jun 2018, 15:35
by viper12
I wonder why they decided in the NDIA Armaments Forums slides to study the shells' effects with FORTY-SIX people stacked in a 16x16ft room. That's basically the density of a crowded elevator...

Re: Of DAS, EOTS etc..

Unread postPosted: 14 Jun 2018, 18:10
by wrightwing
I'd be curious to know what upgrades the F-22 is getting to its AAR-56 (or follow on sensors.)

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jun 2018, 04:33
by charlielima223
wrightwing wrote:I'd be curious to know what upgrades the F-22 is getting to its AAR-56 (or follow on sensors.)


I would like it to be more "DAS-ish" in nature. It doesn't need to provide imagery for the pilot but it would be very awesome if it could provide cueing and ID.

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jun 2018, 05:44
by hornetfinn
charlielima223 wrote:
wrightwing wrote:I'd be curious to know what upgrades the F-22 is getting to its AAR-56 (or follow on sensors.)


I would like it to be more "DAS-ish" in nature. It doesn't need to provide imagery for the pilot but it would be very awesome if it could provide cueing and ID.


I think it would be relatively easy to show the interesting imagery (like ID'd target) in the cockpit displays. There seems to be interest for upgrading the system:
https://www.themaven.net/warriormaven/air/air-force-preps-f-22-for-2060-new-sensors-radar-avionics-ai-BMw9vbS3xk2dymJlS4PW2g/

Specifically, Merchant said, F-22 engineers were already exploring a lightweight DAS-like sensor system for the F-22, able to bring advanced tech to the F-22 without compromising stealth advantages or maneuverability.

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jun 2018, 07:19
by weasel1962
Last I heard, it was supposed to be SAIRST lite with increment 3.3. Not sure the status of 3.3. Likely into the next decade.

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jun 2018, 18:31
by marauder2048
viper12 wrote:I wonder why they decided in the NDIA Armaments Forums slides to study the shells' effects with FORTY-SIX people stacked in a 16x16ft room. That's basically the density of a crowded elevator...


IIUC, ( per the "WarheadView Analysis Interpretation of Results" slide) that just represents the
possible single personnel positions in a room which are then used compute an average and
maximum probability of incapacitation for a single personnel target in the room.

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jun 2018, 22:26
by viper12
That would indeed be legit for computing averages ; the one thing I'm unsure after re-reading these slides is whether these 46 mannequins were physical or imaginary. If they were physical (and made of something relatively dense and solid), they may have impeded the fragments' flight.

Re: Of DAS, EOTS etc..

Unread postPosted: 16 Jun 2018, 01:53
by marauder2048
viper12 wrote:That would indeed be legit for computing averages ; the one thing I'm unsure after re-reading these slides is whether these 46 mannequins were physical or imaginary. If they were physical (and made of something relatively dense and solid), they may have impeded the fragments' flight.


I think they are computer simulated personnel targets but the fragment velocities/trajectories/sizes are
computed or inferred from the actual test firings.

Re: Of DAS, EOTS etc..

Unread postPosted: 03 Jul 2018, 11:36
by hornetfinn
Really interesting regarding DAS and EOTS capabilities:

viewtopic.php?f=58&t=12237&p=397268&hilit=Verification+3519#p397268

Dragon029 wrote:Air System Design Papers:
F-35 Mission Systems Design, Development, and Verification 6.2018-3519.pdf



The EOTS’s functionality consists of a TFLIR image, laser range finder/designator, laser spot tracker, and IRST,
as shown in Fig. 11. The EOTS uses low-profile gimbals with an optical system that maintains boresight accuracy
between the forward-looking infrared (FLIR) and laser functions. Precise stabilization of the EOTS’s line of sight is
achieved by gyro-controlled AZ and EL gimbals, and fine stabilization is achieved through a fast-steering mirror.
Equipped with a staring 1024-by-1024-element MWIR focal plane array, the EOTS is a dual-FOV system. The narrow
FOV is optimized for targeting functions, and the wide FOV is developed to maximize search performance.


So it seems like EOTS is technologically pretty much on par with latest operational podded targeting systems (save for SWIR and/or EO channels in some very latest pods) and clearly superior to any fielded fighter IRST system. Pretty impressive for built-in and fully integrated system.

Interesting things about DAS:

The program required a 360-degree spherical coverage missile warning system. The EO DAS consists of six identical
MWIR sensors distributed on the aircraft, each with a corresponding airframe window panel. The sensors are installed
such that their respective FOVs (95-degree AZ and EL) overlap to provide total spherical coverage. This EO DAS
subsystem provides the pilot with both an MWIR tracking capability and FLIR visual scene, but its FLIR is more
comprehensive. In legacy FLIR systems the pilot’s visual scene was limited to the forward sector. With the F-35’s EO
DAS, the pilot has a 360-degree spherical view of the environment. This allows for a true synthetic vision system, with
the image displayed on the pilot’s helmet-mounted display (HMD).


So this seems to confirm some earlier statements about 95-degree coverage by each sensor. Nothing about resolution though.

Re: Of DAS, EOTS etc..

Unread postPosted: 03 Jul 2018, 15:05
by sprstdlyscottsmn
hornetfinn wrote:So this seems to confirm some earlier statements about 95-degree coverage by each sensor. Nothing about resolution though.

So, does it make more or less sense to put a better resolution array on a wide angle staring unit than one with adjustable FOV? No reason for it to be less than what is used on EOTS, and having the coverage confirmed is awesome. These are a gold mine.

Re: Of DAS, EOTS etc..

Unread postPosted: 03 Jul 2018, 15:43
by Dragon029
It does certainly bolster the previous data that indicated that the DAS sensors are 1k x 1k arrays.

Re: Of DAS, EOTS etc..

Unread postPosted: 04 Jul 2018, 01:27
by madrat
With mirrors and crystal prisms you can have multiple focal arrays fed off one port. With stealth being critical, it's truly the port size, not the focal array density, that is your definitive technological limitation. If this was 1980 you wouldn't have the optics to even see at today's ranges or with anywhere near the available spectrum. It's already amazing what the original F-35 optics began. Now think how exciting it would be to see what they aren't revealing in public sources.

Re: Of DAS, EOTS etc..

Unread postPosted: 04 Jul 2018, 07:17
by hornetfinn
sprstdlyscottsmn wrote:
hornetfinn wrote:So this seems to confirm some earlier statements about 95-degree coverage by each sensor. Nothing about resolution though.

So, does it make more or less sense to put a better resolution array on a wide angle staring unit than one with adjustable FOV? No reason for it to be less than what is used on EOTS, and having the coverage confirmed is awesome. These are a gold mine.


IMO it'd be really strange if the EODAS resolution was less than in EOTS. If I had to bet, it likely has equal resolution due to timeline of their development and imagery seen in public. It could also be possible that EODAS uses higher resolution (2Kx2K) detector as such detectors were available over a decade ago. This was the state of the art ten years ago:
https://www.raytheon.com/news/rtnwcm/gr ... g_pdf2.pdf

Those documents definitely are a goldmine of information regarding F-35. :drool:

Re: Of DAS, EOTS etc..

Unread postPosted: 05 Jul 2018, 08:53
by hornetfinn
madrat wrote:With mirrors and crystal prisms you can have multiple focal arrays fed off one port. With stealth being critical, it's truly the port size, not the focal array density, that is your definitive technological limitation. If this was 1980 you wouldn't have the optics to even see at today's ranges or with anywhere near the available spectrum. It's already amazing what the original F-35 optics began. Now think how exciting it would be to see what they aren't revealing in public sources.


This is very true. That kind of concept has been used in ARGUS-IS and Gorgon Stare system before albeit using visible light and not IR. Using IR sensors instead would be pretty straightforward and AFAIK there is also ARGUS-IR which works in IR. Of course such mosaic of FPAs needs processing power to stitch the images together but that's not much of a problem anymore. I think we might well see some future EODAS sensor with such a sensor when that technology is mature and becomes cheap enough. It's not that easy though and will take time as evidenced by the fact that there aren't more of this kind of systems outside of astronomical sensors.

Re: Of DAS, EOTS etc..

Unread postPosted: 15 Jul 2018, 21:13
by sprstdlyscottsmn
Just a thought, if the DAS can provide 20/40 display to the visor then the largest possible degrees per pixel would be 0.03333, which at 95deg FOV corresponds to a 2,850x2,850 array. Corresponds to a 35ft pixel coverage at 10nm which is plenty for frontal aspect detection of a fighter.