Re: Of DAS, EOTS etc..
Posted: 20 May 2015, 14:53
'This article' link does not work for me with two browsers: http://www.wpafb.af.mil/news/story_prin ... =123066261
Dragon029 wrote:This article and this data sheet confirm it; the EODAS system uses L3's 4MP sensor.
Specifically; you can see the edges of the FPAs on the new 4" diameter wafer; if you use an image editing or CAD program you can then see for yourself that a 1.2" (30.7mm) sided FPA (as per the datasheet) creates the exact same pattern scale as in the AFRL image.
It's possible that it's just a 1MP sensor; L3 doesn't have a datasheet for their 1MP sensor, and it's not uncommon to use (eg) 4MP arrays downsampled to achieve a more reliable or better quality 1MP image. However, the fact that they don't provide a datasheet for the 1MP sensor, plus the fact that the EODAS sensor is physically larger than the 2MP sensor in the HMDS, and needs to achieve a decent level of resolution over it's ~120 degree FOV means that it's almost certain that it has a resolution of 4MP.
The 16MP sensor is twice the width / height of the 4MP and wafer size is measured in diameter by convention, so it's (unfortunately, and only just for now) not the 16MP sensor.
spazsinbad wrote:'This article' link does not work for me with two browsers: http://www.wpafb.af.mil/news/story_prin ... =123066261
bring_it_on wrote:Here you go
https://www.scribd.com/doc/254279654/First-Electro-Optical-System-of-the-21st-Century
Military Avionics Systems
2006 Ian Moir and Allan G. Seabridge; John Wiley & Sons, Ltd. ISBN: 0-470-01632-9
"...The distributed aperture system (DAS) being developed by Northrop Grumman together with BAE SYSTEMS comprises six EO sensors located around the aircraft to provide the pilot with 360° situational awareness information that is detected by passive means. The concept of horizontal coverage of the DAS is depicted in Figure 5.37. The six DAS sensors provide a complete lateral coverage and are based upon technology developed for the BAE SYSTEMS Sigma package (shown in the inset). Key attributes are dual-band MWIR (3–5 mm) and LWIR (8–10 mm) using a 640 x 512 FPA. Each sensor measures ~7 x 5 x 4 in, weighs ~9 lb and consumes less than 20W. Sensor devices with megapixel capability (1000 x 1000) are under development and will be incorporated...."
Source: http://www.helitavia.com/books/Mil%20Av ... ystems.pdf (10.4Mb)
The company had delivered three sets of EO DAS sensors to JSF prime contractor Lockheed Martin for its mission systems integration lab in Fort Worth, for the Cooperative Avionics Test Bed (CATBird) aircraft, and for BF-4, the first F-35 slated to fly with the system. Bouchard said CATBird, a modified Boeing 737, will start flying with mission systems hardware this fall, including the AESA radar. The EO DAS "is about nine months to the right of radar," he said, putting its first flight on CATBird in latter 2009 and on F-35 in 2010.
Dragon029 wrote:It's possible that it's just a 1MP sensor; L3 doesn't have a datasheet for their 1MP sensor, and it's not uncommon to use (eg) 4MP arrays downsampled to achieve a more reliable or better quality 1MP image.
hornetfinn wrote:If we assume that DAS uses 4M array and it has a field of view of 120 degrees, we can calculate the following:
uclass wrote:hornetfinn wrote:If we assume that DAS uses 4M array and it has a field of view of 120 degrees, we can calculate the following:
FoV is stated as 90deg in those links and 95deg in AirForces Monthly F-35 special.
The advanced features of the DAS include missile and aircraft detection, track, and
warning for the F-35. DAS also gives a pilot 360° spherical
day/night vision, with the capability of seeing through the
fl oor of the aircraft. And because the DAS is a passive
system, the pilot does not have to point a sensor in
the direction of a target to gain a track. Comprising six
infrared (IR) sensors (each housed in an aperture)
located around the aircraft, Northrop Grumman
classes the DAS as an integrated system and not a
sensor or a series of sensors.
The six apertures each provide 95° fi eld of regard and
a total of 570° to ensure suffi cient overlap in coverage
around the aircraft.
One aperture is positioned on either side of the radome
below the chine line (the right and left side apertures), one in front of canopy (upper
forward), one in front of the refuelling receptacle (upper aft) and two on the under fuselage
(the lower forward and lower aft) one pointing forward and one aft, but not straight down.
The six apertures are positioned so that no part of the aircraft blanks out its view. The
system receives threat information from all directions and stitches it together to give a
simultaneous three-dimensional spherical view, using that information to protect the aircraft.