Breadloaf shaped blister on bottom forward fuselage?

Cockpit, radar, helmet-mounted display, and other avionics
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BELA

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Unread post13 Jan 2017, 18:49

Apologies if Im late to the party again, but Im not sure which system this part belongs to... MadL? Das? datalink? I havent been able to find any close up pictures? anyone know what it is?
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Unread post13 Jan 2017, 18:53

The circled item? That is the lower FORE/AFT EODAS aperture.
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Unread post13 Jan 2017, 18:56

^^^
What he said.

Here are all of the EODAS apertures.

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Unread post13 Jan 2017, 18:58

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Unread post14 Jan 2017, 00:58

SpudmanWP wrote:^^^
What he said.

Here are all of the EODAS apertures.

Image

And here I had been thinking that two of them were on the wing tips.
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Unread post14 Jan 2017, 02:24

Something that also might be useful to know is that the cheek cameras point to the left and to the right, while the nose one (just ahead of the cockpit) points in the forward upward (diagonal) direction, while the one behind the cockpit points in the rear upward (diagonal) direction, and the two on the bottom point to the forward downward (diagonal) direction and rear downward (diagonal) direction. So their orthogonal directions are not forward, up, rear, and down, but are instead diagonal. (Far as I know the cheek cameras point directly left and right.)

It's also interesting to note that the DAS isn't "truly" spherical, since presumably the rudders obscure part of the view from the "rear upward" camera. I'm sure at some point someone like David Axe or Bill Sweetman will point this out "it's easy to get behind the F-35, you just need to stay just to the left or to the right of the 6 o'clock so its DAS can't see you". Just like how the Eurofighter guys said they can see the F-35 no problem, they just need an AWACS situated around 20-30 degrees off from the F-35's likely incoming direction "because it has a radar spike at that angle" from their eyeball RCS calculations.
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Unread post14 Jan 2017, 03:00

'vanshilar' said above: "...DAS isn't "truly" spherical..." There is a bit of mumbo jumbo in this article which you may grok.

Search the F-35 Forum for Carey + other words for relevant info I reckon.
‘Game-Changing’ EO DAS Nears Action on Joint Strike Fighter
01 Aug 2008 Bill Carey

"As a fifth-generation, multirole fighter, the F-35 Lightning II brings a lot to the table in terms of stealth, lethality and survivability. One "transformational" system that is quietly nearing flight on the aircraft is the Electro-Optical Distributed Aperture System (EO DAS).

Designated AN/AAQ-37, the EO DAS is comprised of six infrared sensors, flush-mounted around the aircraft to afford 360-degree, spherical coverage — in mathematical terms "4 pi steradian." The sensor array will provide the F-35 pilot with missile-warning, situational awareness and navigation FLIR, operating simultaneously, in one package. Integrated via the mission computer, the system will support target detection and identification functions of the aircraft’s Electro-Optical Targeting System (EOTS) and AN/APG-81 active electronically scanned array (AESA) radar....

..."Most people think of us as the radar company [but] this is the real game-changer for the F-35 that separates it from the F-22 and the F-18," said Dave Bouchard, director of JSF Programs. "The F-22 has a very basic missile launch detection system; this is a significant game-changing capability."

Said Pete Bartos, marketing director for Combat Avionics Systems, "People really don’t get what DAS does. It’s just one of those unknown, very core pieces of the JSF that, by the way, no other airplane in the world has."...

...Data collected during flight tests has been used to develop and optimize algorithms that process sensor data — where the real functionality of the system lies, Bouchard said. "In the algorithms, we seamlessly stitch together two or three cameras depending on the field of regard. Our requirement is to have seamlessly stitched, near 20/20 visual acuity," he said. Extremely fast update rates are required to prevent latency of the DAS imagery, which will be projected onto the pilot’s helmet-mounted display. "It has to be updated fast enough so the eye can’t tell it’s a video image as opposed to the real image," he said....

...At this writing, Northrop Grumman’s BAC 1-11, mounted now with a full set of six sensors, had flown more than 100 hours with the EO DAS. The time flown is more impressive, Bartos said, when considering that DAS sensors collect a terabyte per hour of data. That information is archived by the company to check system performance. However, the baseline F-35 has no data storage mechanism, and using the system to track a missile, for example, "will be like taking a sip out of a fire hydrant," he said....

...The executives rolled a video that had been prepared for the Farnborough Airshow with previously unreleased EO DAS imagery. The narrator sings the praises of the system’s many capabilities, which include missile warning and launch-site detection, continuous tracking and ID correlation during aerial combat, day and night vision around the aircraft, including through the floor, and high off-boresight target designation.

"In the age of high off-boresight weaponry and highly maneuverable aircraft, hesitation means defeat," intones the narrator. "... With DAS, maneuverability is irrelevant. Instead of mutual kills, the F-35 simply exits the fight, and lets its missiles do the turning."

Source: http://www.aviationtoday.com/av/militar ... 24687.html

IS LM PR telling an outright LIE here below? NG not specific: http://www.northropgrumman.com/Capabili ... fault.aspx
Mission Systems and Sensor Fusion
no date LM PR

"...Distributed Aperture System
The F-35’s Distributed Aperture System (DAS), developed by Northrop Grumman, is the only 360-degree, spherical situational awareness system. The DAS sends high resolution real-time imagery to the pilot’s helmet from six infrared cameras mounted around the aircraft, allowing pilots to see the environment around them – day or night – without loss of quality or clarity. With the ability to detect and track approaching aircraft from any angle, the DAS also greatly reduces the potential for mid-air collisions and virtually eliminates surprises.

The DAS is completely integrated with other sensors within the aircraft, so if the F-35′s radar detects something of interest, DAS’s software will closely analyze it and make the pilot aware of potential threats. When there are multiple threats, the DAS is able to identify the highest value targets and recommend the order in which to deal with each threat. This “data fusion” provides F-35 pilots with a significant advantage over other pilots, simplifying and managing a vast array of information for the pilot, who must quickly evaluate a complex range of options in a hostile, tactical air combat environment.

The DAS provides:
---- • Missile detection and tracking
---- • Launch point detection
---- • Situational awareness IRST & cueing
---- • Weapons support
---- • Day/night navigation
---- • Fire control capability
---- • Precision tracking of wingmen/friendly aircraft for tactical maneuvering...."

Source: https://www.f35.com/about/capabilities/missionsystems
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post14 Jan 2017, 03:51

spazsinbad wrote:'vanshilar' said above: "...DAS isn't "truly" spherical..." There is a bit of mumbo jumbo in this article which you may grok.


Yes, but although the software stitches multiple views together when there's an overlap, I don't think any of the cameras can see in that direction though, in the region where the two rudders obscure that upper rearward camera. The bottom rearward camera *might* be able to see somewhat in that direction due to the way the rear fuselage curves upward to either side of the engine, but I don't think there's enough of an angle there. The cheek cameras are going to be obscured by the inlets.

Realistically it's basically two thin vertical slices in the rear that's obscured, so it's not something that's going to be a problem operationally, nor is it something that can be taken advantage of by an enemy, especially if the F-35 is maneuvering around. That's why I compare it to the wing planform RCS spike thing -- fun for making nonsensical assumptions like the Eurofighter guys but not something that's actually realistic in the real world.

(BTW, the Eurofighter thing: https://www.flightglobal.com/news/artic ... 35-345265/

"In an internal simulation series, Eurofighter found that four Typhoons supported by an airborne warning and control system (AWACS) defeated 85% of attacks by eight F-35s carrying an internal load of two joint direct attack munitions (JDAM) and two air-to-air missiles, Penrice says.

According to Laurie Hilditch, Eurofighter's head of the future requirements capture, the F-35's frontal-aspect stealth can be defeated by stationing interceptors and AWACS at a 25º to 30º angle to the F-35's most likely approach path to a target. ")
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Unread post15 Jan 2017, 05:40

We can always put that claim to a REAL test.

My money is on the F-35.
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Unread post15 Jan 2017, 07:24

vanshilar wrote:https://www.flightglobal.com/news/artic ... 35-345265/

"In an internal simulation series, Eurofighter found that four Typhoons supported by an airborne warning and control system (AWACS) defeated 85% of attacks by eight F-35s carrying an internal load of two joint direct attack munitions (JDAM) and two air-to-air missiles, Penrice says.

According to Laurie Hilditch, Eurofighter's head of the future requirements capture, the F-35's frontal-aspect stealth can be defeated by stationing interceptors and AWACS at a 25º to 30º angle to the F-35's most likely approach path to a target. ")


Let's assume for discussion's sake this is accurate. Barracuda will detect threat emissions and the F-35s will simply resort to the 15% of approaches that are undetected... Result: a very bad day for AWACS and Typhoons.
Last edited by popcorn on 16 Jan 2017, 00:16, edited 1 time in total.
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Unread post15 Jan 2017, 17:00

Even 4th gen pilots have a hard time throwing out their concept of how things work. The F-35 is a new game. It's an impossibility for us armchair guys who have never even flown or been involved in missions to get a true handle on... We don't even know what the classified systems are, let alone how they work. Misinformation about a platform can be a tactic in and of itself,

accepting for the moment that there are blind areas within the eo-das sphere. Who flies in a straight line is a battle space anyway? That puts to end any discussion on the degree angle and such. Even a minor course alteration gives the computers all the data in the battlespace. The basic flying of the plane is automated, the pilot puts in waypoints. The computer uses the sensors to work out the best way to get there through the battlespace. The computer alerts the pilot to a threat, the pilot isn't spending all his time flying the plane and looking for them.
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Unread post15 Jan 2017, 22:11

vanshilar wrote:
spazsinbad wrote:'vanshilar' said above: "...DAS isn't "truly" spherical..." There is a bit of mumbo jumbo in this article which you may grok.


Yes, but although the software stitches multiple views together when there's an overlap, I don't think any of the cameras can see in that direction though, in the region where the two rudders obscure that upper rearward camera. The bottom rearward camera *might* be able to see somewhat in that direction due to the way the rear fuselage curves upward to either side of the engine, but I don't think there's enough of an angle there. The cheek cameras are going to be obscured by the inlets.

Realistically it's basically two thin vertical slices in the rear that's obscured, so it's not something that's going to be a problem operationally, nor is it something that can be taken advantage of by an enemy, especially if the F-35 is maneuvering around. That's why I compare it to the wing planform RCS spike thing -- fun for making nonsensical assumptions like the Eurofighter guys but not something that's actually realistic in the real world.

(BTW, the Eurofighter thing: https://www.flightglobal.com/news/artic ... 35-345265/

"In an internal simulation series, Eurofighter found that four Typhoons supported by an airborne warning and control system (AWACS) defeated 85% of attacks by eight F-35s carrying an internal load of two joint direct attack munitions (JDAM) and two air-to-air missiles, Penrice says.

According to Laurie Hilditch, Eurofighter's head of the future requirements capture, the F-35's frontal-aspect stealth can be defeated by stationing interceptors and AWACS at a 25º to 30º angle to the F-35's most likely approach path to a target. ")

According to Eurofighter marketing, its competitor can't ________. What has never been demonstrated, is detecting an F-35 by using the means described. Given the assumptions- "Eurofighter, however, claims the F-35 lacks all-aspect, very low observable stealth, and is vulnerable to detection and defeat by non-stealthy opponents" I wouldn't put a lot of faith in any of the assertions.
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Unread post15 Jan 2017, 22:16

As for spherical coverage, each camera is extremely wide angle, overlapping the FOV, of the other cameras. There are no gaps, for any practical purpose.
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Unread post17 Jan 2017, 00:48

Probably these two PDF pages have been posted already but here we go again from:
LIGHTNING II
26 Apr 2012 Mark Ayton, KEY Pubs Special Edition

"...Spherical View
"Mark Ayton describes the Northrop Grumman AAQ-37 Distributed Aperture System for the F-35....

..."...The six apertures each provide 95° field of regard and a total of 570° to ensure sufficient 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...."

CGI spherical view image: "This computer generated image shows the spherical coverage provided to the aircraft by the AAQ-37 DAS."

3view Image: "Approximate positions of the six infrared sensors on the aircraft are shown is this diagram."


CVN Day/Night DAS view will be posted elsewhere also...
CVN Day/Night HMDS DAS View: "Day (right) and night (left) imagery of a US Navy aircraft carrier as fed by the DAS to the helmet mounted display."

AND... we see the luverlay DAS NIGHT Horizon on the LEFT - NIGHT DAS VIEW!

Source: http://militaryrussia.ru/forum/download ... p?id=28256 (PDF 12+Mb)
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F-35DAScgiSphericalCoverageOverlapCROP.jpg
F-35 DAS Coverage 6 Sensors.jpg
F-35CnightDayDASview.jpg
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Unread post17 Jan 2017, 03:14

spazsinbad wrote:Probably these two PDF pages have been posted already but here we go again from:
LIGHTNING II
26 Apr 2012 Mark Ayton, KEY Pubs Special Edition

"...Spherical View
"Mark Ayton describes the Northrop Grumman AAQ-37 Distributed Aperture System for the F-35....

..."...The six apertures each provide 95° field of regard and a total of 570° to ensure sufficient 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.


Yeah the reason I posted about the directions the EODAS points to is because the graphic is wrong (even though yes, it was produced by Northrop Grumman) -- it shows the EODAS as having cameras pointing straight forward, straight up, straight back, and straight down. The text does it have it right though, although the 95°field of regard with 6 cameras doesn't really mean 570° -- since it's spherical, along each axis there are only 4 cameras for a 380° field of regard (with the exception of if you're taking a slice of the sphere diagonally such that it cuts across the corners of all 6 cameras).

Incidentally, this also means that the side cameras are probably mounted diagonally, i.e. like a diamond, rather than flat with the ground.

Also, obviously there's been discussion about the DAS before, such as here:

viewtopic.php?f=62&t=26505&start=30

It's likely that the 95 degree field of regard is talking about the top-to-bottom and left-to-right field of regard when the (square) sensor is mounted in the system, not the lens itself. Thus yes the corners of the sensor means that if you measure corner to corner, the field of regard is greater than 95 degrees. So there's no "missing corner" that doesn't get seen. The same confusion happens when people talk about display/projection technology (and it's even more confusing there because displays are rectangular not square).

By the rudder obstructing the DAS view, what I mean is that from the angle shown in the attached image (assuming I lined it up properly such that the rudder obstructs the view from the top rear DAS camera), I don't see where there's a DAS camera that can look to this particular angle, and I don't think the cheek cameras can see out this far back. So that's what I mean, there's probably two vertical strips missing from the spherical DAS coverage. Nevertheless, I think of it more as just one of those "little nits" with the system and not something that is ever useful or detrimental operationally, in the same way that planform alignment means there's an RCS spike at that particular angle but it doesn't really detract from a plane's stealth, and for exactly the same reason -- because the plane is constantly moving and changing its location and orientation so these "momentary" glimpses are not something you can take advantage of.
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