DAS targeting vs radar targeting

The F-35 compared with other modern jets.
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blindpilot

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Unread post03 Feb 2018, 22:43

element1loop wrote: ... stuffed that up, humble apologies.


Plus 10 on the respect scale. That's a great start. I know it wasn't aimed at me, but I do say, no harm no foul.
element1loop wrote:
blindpilot wrote: ... I'm assuming (I have to .. need[y[?]] to know and all) your background allows you hear...

... ssheshchesh ...


As to my asking you as to where you are coming from, it is only to try to be responsive to your line of thinking, in a framework you recognize. Without it we'll (all of us) just keep shooting in the dark. Clearly as the conversation indicates we're talking past each other a great deal. That's the need. There is no needy ... been there, done that, bought the T-shirts, got the post cards ... am now just enjoying fishing with the little ones. Most here are just trying to hear what you're saying so that replies will be of some value, perhaps even for you. And who knows, if we discern where you are coming from, we might get something from your comments as well.

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Unread post03 Feb 2018, 23:53

element1loop wrote:Yeah, sorry Spud (and Steve), I really thought it was from another thread.... stuffed that up, humble apologies.


It's all good... we've been there.

I often suffer from PCP (Pre-Coffee Posting) :mrgreen:
"The early bird gets the worm but the second mouse gets the cheese."
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element1loop

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Unread post04 Feb 2018, 01:12

Thanks guys, not my best moment, cheers.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
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element1loop

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Unread post04 Feb 2018, 02:53

botsing wrote:I think you should let go of the "one lonely fighter on it's own" idea.


Yes, and no. Yes, obviously support is baked-in to the concepts of joint 5th ops. But take note that USAF is looking at concentrating communication/translation for data support between jet types, in RQ-4s (and I'm not criticising that, either, btw). That may not be a single point of failure, but it is one for s serious degradation of support options when you need them.

We have to expect things to not go to plan, or in ideal or expected ways, then still have the options pre-stacked on our side, as attrition or support limits, and degrading are being met.

This is going to occur at different thresholds for each country that is operating F-35s.

So it will remain relevant to discuss a single aircraft case, for good reason, and will remain essential, especially in proliferating cheap(er) EA and cyber (both of unknowable effectiveness, so worst case must be considered).

Plus I'm illustrating a concept which is best discussed in that way. But it is not how I think re an actual contemporary fight, and how to sync to win it.

botsing wrote:F-35 is developed as a part of a much bigger integrated system of systems. This means you can perform optimizations on single nodes (e.g. only frontal sphere EOTS) due to redundancy with other nodes (e.g. Other F-35, UAV, satellites that can cover the other parts).

Advantages are the removal of single point of failures, redundancy, lower weight, distributed sensor coverage and so on.


This is not a good argument B, a DAS ranger is hardly going to add much weight, nor cost. This is an investment worth every cent. And re redundancy, if an IR missile or fighter is coming at you fast, you will have no quibbles or doubts that you want that redundancy onboard, and in the DAS, and not just the EOTS.

As regards complexity, this is the tool you want to get right, complexity is not a reason to flinch or balk at it, on the contrary, you need to do it first and do it best.

botsing wrote:If DAS has no laser rangefinder then I think it is more oppertune to theorize why that decision was made, instead of using limited information to criticize the designers.


I personally think that's a big if - I don't consider that to be the case at all. You are right, that it is likewise a theory that DAS is not already an auto-ranging, auto-IDing, auto-classifying, auto-prioritising A2A/A2G targeting system.

From my POV that is what I've read from the very beginning of DAS development (despite others insisting I must be a dope and was really unknowingly reading about EOTS, instead ... nope), and it is (for me), curious that others came up with the counter theory they hold, based on ... prop photos.

Well get this, some of the very same DAS photos were in the article that I read back then! ...lol. They are predevelopment prototypes and others probably props.

No one is going to show the internet the real deal - right?

Wow.

Not trying to be provokative here, but that's how I really see it, and have done so for a very long time now. I'm a bit miffed by this alternate reality.

Now ... "criticizing designers" ... !

I haven't and wouldn't. And that's a bit strange interpretation, B.

On the contrary, I think they nailed it, people just haven't recognised and processed that fully, yet ... perhaps there's a prevailing overdose of rectitude ... perhaps ease up on 'virtue-signaling' some. It's OK to explore ideas, it's not OK to suppress that, because it might be perceived in some unintended way, by others. Not my problem.

I have no issue of any kind with 'designers', just maybe with some of the various interpretations of what it can do, and how it can be used .... and even that's relatively minor.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
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blindpilot

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Unread post04 Feb 2018, 04:24

element1loop wrote:...
Yes, and no. .. take note that USAF is looking at concentrating... That may not be a single point of failure, ...
We have to expect things to not go to plan, ....
... it will remain relevant to discuss a single aircraft case,... worst case must be considered).
Plus I'm illustrating a concept which is best discussed in that way. But it is not how I think re an actual contemporary fight, and how to sync to win it.....This is not a good argument B, a DAS ranger is hardly going to add much weight, nor cost. This is an investment worth every cent. ...As regards complexity, this is the tool you want to get right, complexity is not a reason to flinch or balk at it, on the contrary, you need to do it first and do it best.
...
From my POV that is what I've read from the very beginning of DAS development ... curious that others came up with the counter theory they hold, based on ...
No one is going to show the internet the real deal - right?
...
Not trying to be provokative here, but that's how I really see it, and have done so for a very long time now. I'm a bit miffed by this alternate reality.
.

I really am trying to get my mind around where you are coming from. Let's just address a few issues that I could use some help on. Specifically the sources of your assertions, in the context of how you have assembled the facts.
Now if you are an electronics engineer for Northrop Grumman, who has worked with sensors before, then we might try and drill down on where we disagree and why, but you have to understand ...
On this forum we have F-16/F-18/Mig 29/F-22/etc. Multinational pilots, aircraft design engineers, and even a few maintenance types that have actually touched some of the devices we're talking about, and some who have designed similar systems that people paid lotsa of $$$ for those designs.

Obviously classified material constraints might limit the comments of such experts, or even whether they share an opinion, but they (we) aren't a group of people who just read a lot of Aviation Week, and Discovery Magazine.

We obviously disagree on whether the DAS sensor has an active ranging laser in it. If you can just tell us why you say it does, cite an expert's specific statement, or source tech manual, or something ... anything ... I think most of us would listen ... especially if you are a Northrop engineer! But honestly ... despite a great deal of forbearance allowing that perhaps you have such a reason, you have given no substantive basis to accept your assertion ... other than ... if you would have designed it, it absolutely would have to have one.

Okay, so let's even go so far as to allow that as a reasonably possible justification. So for you it absolutely needs it ... Without revealing your secret identity, can you just give us a hint as to if you have, how many you have, ever designed an actual working sensor system for an aircraft... even a Cessna 150? (hint: some of us have)

Element, you have to give us a reason to listen to your assertions, especially when we are pretty sure ... for extremely valid reasons ... that your assertion might be wrong.

There is just no where to take the conversation unless you give us a context to work with you. You don't have to be a Northrop engineer. You can be a student at a university, a journalist with decades of aviation stories, hardware chip designer for Intel .... anything! But you have to frame that for us, if you desire meaningful responses from us. (at least this part of us) On a scale of 1 to 10 with a range 3 to 4, where are you in technical experience/study... job experience ... access to related expert sources, quote from...etc.? Whatever! Where are these ideas coming from other than the fantasy opinion of the void? I like to think it isn't that.

I truly don't mean to insult you, and as I said, wherever you are, the folks here are very good at meeting you where you are at, and seeking to learn from you things that you may not even realize you are expert at.

Beyond that I cannot think of a reply to the above other than I guess ... yes, your POV and alternate reality are not meshing very well, with those here who have respected opinions in the field.

MHO
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Unread post04 Feb 2018, 05:11

I don't see why we focus on laser rangefinder. Since esm can easily pick up anything that emmis radar wave, the question is are there any targets dare To turn off radar?
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Unread post04 Feb 2018, 05:33

I was not aware that the definition of modern IRST requires an integral laser rangefinder. Lacking access to military IRST design requirements, I turned to the next best source: Wikipedia. https://en.wikipedia.org/wiki/IRST does not list an integral laser rangefinder as a requirement of a modern IRST. It does note that
IRST systems can incorporate laser rangefinders in order to provide full fire-control solutions for cannon fire or launching missiles (Optronique secteur frontal). The combination of an atmospheric propagation model, the apparent surface of the target, and target motion analysis (TMA) IRST can calculate the range.


but it also says other methods are available for determining range. Given the system-of-systems fifth generational approach of the F-35, and the computational power available on this aircraft, these other methods are more than sufficient to determine range of targets out to a limit (which I'm sure is classified.)

At the time the F-35 was designed, all other IRST's were either pod mounted or mounted in a single, bulbous fairing, typically on the nose of the aircraft. The decision to distribute the IRST function of the AN/AAQ-37 EODAS system across six sensors spread around the airframe is brilliant, resulting in 360° spherical IRST coverage, hitherto unheard of on a tactical aircraft.

I won't say determining range without a laser rangefinder in each EODAS sensor housing is cheaper, or less complex, than the approach the designers took, as the software required and systems engineering and integration may have been far more complex, but for an aircraft that went through a development standown, the 2004 SWAT process, to shed weight wherever possible, it seems apparent that six fewer laser rangefinders would definitely save weight.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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Unread post04 Feb 2018, 05:52

element1loop wrote:
I do not dispute your points regarding cueing sensor fusion data gathering by complementary sensors (as well).

However, the DAS IS a modern A2A/A2G IRST.

Modern IRSTs DO incorporate aa laser ranger/tracker, in this case into a sensor fusion engine.

The article I read over 12 years ago was specifically about DAS alone, not EOTS at all, and said DAS was intended to have advanced IRST passive targeting from the beginning.

DAS targeting, via laser vector generation, not just detection and tracking, was a well developed concept and AIM for DAS, as long as 15 years ago.

Do you really think they're going to pass up the opportunity to do that in the preceding time interval, when it was already an open source concept and declared aim, early to mid last decade?

I think people simply haven't processed (yet), why it's an IRST.

Are not modrrn recent IRSTs targeting sensors?

Do you know of any that aren't?

The F-35 has SEVEN lethal targeting IRSTs.

EOTS is its long-range optimised IRST.


DAS does not have an integrated LASER range finding capability.

You need to de-couple DAS from other IRST systems. DAS is a system of fixed focal plane arrays, other IRST systems are on mechanically scanned gimbals. A LASER is a very narrow FOV device that must be pointed mechanically to calculate a range solution.

DAS and LASER range finding are technically incompatible, DAS cameras are fixed wide field of view devices, you cannot add a gimbal to DAS that negates the entire purpose, 360 degree simultaneous coverage.
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Unread post04 Feb 2018, 06:33

cheese_e wrote:You need to de-couple DAS from other IRST systems. DAS is a system of fixed focal plane arrays, other IRST systems are on mechanically scanned gimbals. A LASER is a very narrow FOV device that must be pointed mechanically to calculate a range solution.

DAS and LASER range finding are technically incompatible, DAS cameras are fixed wide field of view devices, you cannot add a gimbal to DAS that negates the entire purpose, 360 degree simultaneous coverage.



That makes sense. Looks like my earlier post re DAS.ie ..maybe when DIRCM is integrated on the jet then maybe a laser ranging capability might be a secondary function... maybe" is not feasible and the latter may likely be turreted unit(s) on the fuselage.
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Unread post04 Feb 2018, 07:31

gta4 wrote:I don't see why we focus on laser rangefinder. Since esm can easily pick up anything that emits[sic] radar wave, the question is are there any targets dare To turn off radar?


Since this is your thread I'll try and answer some, although others have done a good job addressing your questions.
The reason for using the laser issue, is that it reflects a presumption, (not the only one) where we can reset the conclusions being asserted. It's just a point of contention that allows a reset for that conversation. Many (even modern) IRSTs do ranging without lasers through several techniques, from obscure atmospheric characteristics analysis to simple triangulation techniques. The advantage of this is first and primarily that they are passive, and don't set off today's ubiquitous laser detection/warning systems.

AWACS and GCI controlled intercepts might reasonably have interceptors run without, or delay radar being turned on. (if those can even see a stealth AC) Also widely spaced wing men can run quiet. There are definitely situations where DAS would be needed as potentially the only detector. Carefully positioned LPI emitting wing men would be another way.

Which addresses your "ESM can easily" statement. There is nothing easy about ESM in AESA frequency agile spectrums. This is another reason the F-35s significantly more powerful computer is a part of the entire integrated system of systems. So yeah the F-35 (and likely F-22) ESM can detect and ID, but maybe not as easily as you stated, for run of the mill 4th gen ESM. (that's why they call it LPD/LPI) Today's world requires families of systems integrated into one fused SA and targeting environment. Even missiles are moving to multi sensors and linked data from the network. That's one reason why the EO or Radar question is a bit off from reality. in the 5th gen world.

MHO,
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Unread post04 Feb 2018, 07:49

cheese_e wrote:
element1loop wrote:The article I read over 12 years ago was specifically about DAS alone, not EOTS at all, and said DAS was intended to have advanced IRST passive targeting from the beginning.

DAS does not have an integrated LASER range finding capability....you cannot add a gimbal to DAS that negates the entire purpose, 360 degree simultaneous coverage.


Thanks cheese_e. BTW in case no one else already did, Welcome to the forum.

Element1loop - The article you read said plainly "passive." Lasers are not passive. There are "advanced" passive ranging techniques for a staring IRST sensors... that don't include lasers.

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Unread post04 Feb 2018, 11:26

blindpilot wrote:
cheese_e wrote:
element1loop wrote:The article I read over 12 years ago was specifically about DAS alone, not EOTS at all, and said DAS was intended to have advanced IRST passive targeting from the beginning.

DAS does not have an integrated LASER range finding capability....you cannot add a gimbal to DAS that negates the entire purpose, 360 degree simultaneous coverage.


Thanks cheese_e. BTW in case no one else already did, Welcome to the forum.

Element1loop - The article you read said plainly "passive." Lasers are not passive. There are "advanced" passive ranging techniques for a staring IRST sensors... that don't include lasers.

BP


Ditto cheese_e, thanks for your input.

BP, the article definitely said lasers, however I of course accept technology options may have moved significantly on in the interim, to achieve similar capability (in a single aircraft context), sans lasers.

I've always considered both passive and active ranging would be present in DAS, passive for most monitoring needs (occasionally lased for confirmation), but precise laser track predominently for IR ambush etc., (LOAL+ datalink), to maximise missile fly-out efficiency, thus also improving its Pk, in ways passive ranging lags.

But a laser gimble does not have to coincide physically with a sensor array, and nor do lasers need mechanical steering via gimble to point a beam. And not physically large or heavy either.

In the end a laser is going to provide track data more precisely and faster than anything else.

Can they be dispensed with? Theoretically yes, that can and is being argued, ... I would say no, that would remove one of the best advantages of an IRST's speed and precision.

Re that article, it equally emphasised DAS laser ranging for monitoring ground contact. It's possible lasers are no longer needed for positioning and tracking ground targets due to high res terrain models allowing them to be placed in the terrain geolocation. So maybe lasers are not needed on DAS for that task any longer, since that article was published.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
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Unread post04 Feb 2018, 12:14

element1loop wrote:Ditto cheese_e, thanks for your input.

Re that article, it equally emphasised DAS laser ranging for monitoring ground contact. It's possible lasers are no longer needed for positioning and tracking ground targets due to high res terrain models allowing them to be placed in the terrain geolocation. So maybe lasers are not needed on DAS for that task any longer, since that article was published.


If DAS is coupled through sensor fusion with SAR or a doppler terrain radar, that would provide distance without the need of a laser.
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Unread post04 Feb 2018, 14:28

kimjongnumbaun wrote:
element1loop wrote:Ditto cheese_e, thanks for your input.

Re that article, it equally emphasised DAS laser ranging for monitoring ground contact. It's possible lasers are no longer needed for positioning and tracking ground targets due to high res terrain models allowing them to be placed in the terrain geolocation. So maybe lasers are not needed on DAS for that task any longer, since that article was published.


If DAS is coupled through sensor fusion with SAR or a doppler terrain radar, that would provide distance without the need of a laser.


Yes, except they are not passive so defeat the purpose of foregoing the laser.

But with a pre-digitized regional terrain model in the MDF the F-35 can use own 3d position and geometry to the contact to determine contact 3d location, on ground, precisely.

Maintains passive stealth.
Accel + Alt + VLO + DAS + MDF + Radial Distance = LIFE . . . Always choose Stealth
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Unread post12 Feb 2018, 12:37

element1loop wrote:
kimjongnumbaun wrote:
element1loop wrote:Ditto cheese_e, thanks for your input.

Re that article, it equally emphasised DAS laser ranging for monitoring ground contact. It's possible lasers are no longer needed for positioning and tracking ground targets due to high res terrain models allowing them to be placed in the terrain geolocation. So maybe lasers are not needed on DAS for that task any longer, since that article was published.


If DAS is coupled through sensor fusion with SAR or a doppler terrain radar, that would provide distance without the need of a laser.


Yes, except they are not passive so defeat the purpose of foregoing the laser.

But with a pre-digitized regional terrain model in the MDF the F-35 can use own 3d position and geometry to the contact to determine contact 3d location, on ground, precisely.

Maintains passive stealth.


But F-35 still has laser in EOTS and that can be used when range data is needed. Laser is also not passive but an active sensor which can be detected. Also tracking does not require range data at all as that can be done without any range data. Of course range data is nice to have in many cases and that can be had with laser, radar, ESM sensors or triangulating with EODAS or other sensors in other F-35s (or even other platforms). There are numerous ways to get range data besides having laser range finder in every EODAS sensor. Having 3D terrain model is also going to help a lot.
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