Of DAS, EOTS etc..

Cockpit, radar, helmet-mounted display, and other avionics
  • Author
  • Message
Offline

sprstdlyscottsmn

Elite 3K

Elite 3K

  • Posts: 3556
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az

Unread post15 Jul 2018, 21:13

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.
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline

wrightwing

Elite 2K

Elite 2K

  • Posts: 2869
  • Joined: 23 Oct 2008, 15:22

Unread post15 Jul 2018, 22:34

sprstdlyscottsmn wrote: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.

What's the pixel size for 20/20? Most of the claims I've seen are "near 20/20 acuity."
Offline

sprstdlyscottsmn

Elite 3K

Elite 3K

  • Posts: 3556
  • Joined: 10 Mar 2006, 01:24
  • Location: Phoenix, Az

Unread post16 Jul 2018, 00:00

Over 5k x 5k. So a 4k x 4k would be "near"
"Spurts"

-Pilot
-Aerospace Engineer
-Army Medic
-FMS Systems Engineer
Offline

marauder2048

Senior member

Senior member

  • Posts: 335
  • Joined: 14 Mar 2012, 06:46

Unread post16 Jul 2018, 06:33

sprstdlyscottsmn wrote:Over 5k x 5k. So a 4k x 4k would be "near"


Consider that at 16 Megapixels, 12-bits per pixel and 30 Hz you could very easily
saturate the available fiber channel bandwidth.
Online

SpudmanWP

Elite 3K

Elite 3K

  • Posts: 7752
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post16 Jul 2018, 16:27

Given that each EODAS unit is connected via fiber optics to the avionics bay, it's just a matter of upgrading the transceivers to handle the bandwidth as capacities increase. Besides 4k * 30hz * 12 bit = Bandwidth Per Channel of 6.72 Gbps which is perfectly fine for fiber.

Https://k.kramerav.com/support/bwcalculator.asp

However, 8Gbps FC was not available in the early 2000's (2Gbps in 2001, 4Gbps in 2004, etc).

Https://en.wikipedia.org/wiki/Fibre_Channel

The workaround would obviously be only streaming data that is needed (eg hi-res data of area of interest, relevant view for HMDS, etc).
"The early bird gets the worm but the second mouse gets the cheese."
Offline

marauder2048

Senior member

Senior member

  • Posts: 335
  • Joined: 14 Mar 2012, 06:46

Unread post17 Jul 2018, 02:27

SpudmanWP wrote:Given that each EODAS unit is connected via fiber optics to the avionics bay, it's just a matter of upgrading the transceivers to handle the bandwidth as capacities increase. Besides 4k * 30hz * 12 bit = Bandwidth Per Channel of 6.72 Gbps which is perfectly fine for fiber.

Https://k.kramerav.com/support/bwcalculator.asp

However, 8Gbps FC was not available in the early 2000's (2Gbps in 2001, 4Gbps in 2004, etc).


There's ~ 20% encoding overhead so even 8 Gbps couldn't handle it. That changed with 10 GFC though.

SpudmanWP wrote:The workaround would obviously be only streaming data that is needed (eg hi-res data of area of interest, relevant view for HMDS, etc).


There was a suggestion in at least one article that they do some processing (possibly compression) at the sensor front-ends.
Offline
User avatar

spazsinbad

Elite 3K

Elite 3K

  • Posts: 21377
  • Joined: 05 May 2009, 21:31
  • Location: ɐıןɐɹʇsn∀¯\_(ツ)_/¯
  • Warnings: -2

Unread post17 Jul 2018, 10:52

Raytheon’s DAS Sensor: Weighs Less, Uses Less Power, Lockheed Says
16 Jul 2018 Colin Clark

"...Greg Ulmer, the new head of Lockheed’s F-35 program, describes here why the company went with Raytheon’s sensor. He offered new details about it, noting it weighs less than Northrop’s and uses less power than does the current version."

Source: https://breakingdefense.com/2018/07/ray ... heed-says/
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
Online

SpudmanWP

Elite 3K

Elite 3K

  • Posts: 7752
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post17 Jul 2018, 16:30

I would sure hope so given the last 15+ years of component miniaturization and power improvements. It makes complete sense that it would be smaller along with cheaper, more durable, and more powerful to boot.
"The early bird gets the worm but the second mouse gets the cheese."
Online

SpudmanWP

Elite 3K

Elite 3K

  • Posts: 7752
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post17 Jul 2018, 19:54

Ulmer highlighted the recent award to Raytheon of a contract to replace Northrop Grumman as the supplier of the Distributed Aperture System (DAS) on future F-35 production aircraft. Raytheon’s product is twice as capable and five times more reliable, while saving 10 to 15 pounds (4.5 kg to 6.8 kg) of weight, he said.


https://www.ainonline.com/aviation-news ... ustainment
"The early bird gets the worm but the second mouse gets the cheese."
Offline

taog

Enthusiast

Enthusiast

  • Posts: 32
  • Joined: 12 Dec 2013, 17:36

Unread post04 Sep 2018, 14:49

sprstdlyscottsmn wrote:2x increase in performance huh? Even if that really means twice the number of pixels per sensor for a ~40% increase in range that is very significant. The system already is credited with tracking orbital class launch vehicles from 800nm. A more dubious claim of detecting an AIM-120 launch from 1,200nm has been made, but I would be concerned about that claim at 10% of that range.


5 times the resolution → ~2.23 times the detection range.
So 2x increase in performance refers to the detection distance ?

Northrop’s contract to supply the DAS only extends through 2023, but the company declined to compete for a follow-on contract. Raytheon won the contract beginning with Lot-15 F-35 DAS, which Lockheed Martin’s Skunk Works head and former F-35 lead Jeff Babione said will have five times the resolution of the current DAS at a lower cost.

http://interactive.aviationtoday.com/av ... -learning/
Offline

taog

Enthusiast

Enthusiast

  • Posts: 32
  • Joined: 12 Dec 2013, 17:36

Unread post20 Sep 2018, 13:36

1.
An internal project proposed by LM
2.
Different from Advanced EOTS which adds the SWIR capability and grows the aperture to get significantly improved range performance, this upgraded EOTS will add the LWIR capability for long range air-to-air detection purpose.

3.
St. John said it's very attractive to develop the passive sensor-only killed chain that using multi-ships IRST capability.

4.
They have completed a prototype by their internal funding and provided this concept to JPO office to decide whether inserting this project to block 4 upgrade list.

http://aviationweek.com/awindefense/loc ... grade-f-35
Offline
User avatar

element1loop

Forum Veteran

Forum Veteran

  • Posts: 852
  • Joined: 31 Dec 2015, 05:35
  • Location: Australia

Unread post20 Sep 2018, 17:16

Plus potential for significant sensitivity improvement given the time/tech period since the initial sensor.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
Offline

castlebravo

Active Member

Active Member

  • Posts: 203
  • Joined: 08 Feb 2011, 19:10

Unread post20 Sep 2018, 19:55

marauder2048 wrote:
sprstdlyscottsmn wrote:Over 5k x 5k. So a 4k x 4k would be "near"


Consider that at 16 Megapixels, 12-bits per pixel and 30 Hz you could very easily
saturate the available fiber channel bandwidth.


Wouldn't 12-bits per pixel be a bit extreme for gray-scale?
Offline

hornetfinn

Elite 2K

Elite 2K

  • Posts: 2479
  • Joined: 13 Mar 2013, 08:31
  • Location: Finland

Unread post21 Sep 2018, 13:41

castlebravo wrote:
marauder2048 wrote:
sprstdlyscottsmn wrote:Over 5k x 5k. So a 4k x 4k would be "near"


Consider that at 16 Megapixels, 12-bits per pixel and 30 Hz you could very easily
saturate the available fiber channel bandwidth.


Wouldn't 12-bits per pixel be a bit extreme for gray-scale?


Not really that extreme. For automatic target detection and tracking performance and reliability higher digital resolution is better. In F-35 where all the sensor information is handled by the sensor fusion engine, it would be better if important information is not lost. Since IIR sensors have pretty wide temperature range, having enough bits to show small temperature differences can be crucial for performance (spectral resolution). I'd say that it's just as important as pixel resolution (pixel count).

For human eye 10-12 bit resolution is visibly better than say 8 bit resolution. Difference between 12 and 10 bits is usually not easy to tell, but then the difference in required bandwidth and memory is not big either.

Of course AFAIK, there are ways to significantly improve fiber channel bandwidth in F-35 if required.
Online

SpudmanWP

Elite 3K

Elite 3K

  • Posts: 7752
  • Joined: 12 Oct 2006, 19:18
  • Location: California

Unread post21 Sep 2018, 14:08

I wonder what 5x the resolution will do for CAS, especially in the new forms of ground target detection that was shown a while back.

Image
"The early bird gets the worm but the second mouse gets the cheese."
Previous

Return to F-35 Avionics

Who is online

Users browsing this forum: No registered users and 2 guests