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hobbesmaster posted:It's probably possible with some stupid amount of hardware, there's not too many sparrows traveling over 300mph out there. Fancy pants radars use a combo of hardware and software to mitigate the effectiveness of stealth without also saturating with clutter. Stealth is still a very good thing to have in your wheelhouse but we are still not at the point of "wrap it up radar havers lol" If you want more details see your local recruiting office and be able to hold a clearance. Or go work for a co tractor I guess.
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May 12, 2015 23:45
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Ardeem posted:But no shortage of sparrows that are ~440 feet apart. And therein lies a lot of interesting EE PhDs if it wasn't necessary to be classified.
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May 12, 2015 23:52
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hobbesmaster posted:And therein lies a lot of interesting EE PhDs if it wasn't necessary to be classified. Doctoral thesis on detection of stealth aircraft by Doppler detection of airframe vibration on radar returns, and the avoidance of false positives calculated from the wingbeat of an unladen swallow.
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May 13, 2015 00:00
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African or European?
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May 13, 2015 00:09
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MrChips posted:African or European? Does he look like an ornithologist?
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May 13, 2015 00:10
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Godholio posted:Do you know how many hundreds of sparrows, robins, crows, magpies, treetops, flagpoles, and other miscellaneous things are going to show up if you open your filters that much? You'll almost certainly crash your computer if it even lets you do that. Doesn't this mean that given Moore's Law you're going to have computers being able to brute force detect stealthy aircraft before they are out of service?
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May 13, 2015 00:25
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Oh yeah. poo poo, given how good GPGPUs are at this sort of thing the US should be putting export controls on nvidia by now
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May 13, 2015 00:30
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Linedance posted:Doctoral thesis on detection of stealth aircraft by Doppler detection of airframe vibration on radar returns, and the avoidance of false positives calculated from the wingbeat of an unladen swallow. Thesis mysteriously missing from engineering library.
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May 13, 2015 00:35
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hobbesmaster posted:And therein lies a lot of interesting EE PhDs if it wasn't necessary to be classified. The last time I did a classified advanced electronic attack mission, it was Georgia tech research students being flown around by retired Air Force pilots. It was for their degree. We got a great picture of a beaming pilot next to his emergency landed jet he put down on an abandoned dirt strip standing next to an engineer who looked like he'd died on the way down from stress. So yes, such programs exist.
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May 13, 2015 01:21
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Why did they have to put their plane down?
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May 13, 2015 01:38
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hobbesmaster posted:It's probably possible with some stupid amount of hardware, there's not too many sparrows traveling over 300mph out there. You're not going to get a hit on every bird, every sweep. Keep in mind these radars aren't just pointing at one spot either, they're sweeping 360 or back-and-forth. Good luck keeping track of which loving sparrow is which. Eej posted:Doesn't this mean that given Moore's Law you're going to have computers being able to brute force detect stealthy aircraft before they are out of service? In that timeframe, no, because computers aren't the only limiting factor. You've also got the radar's sweep rate and resolution cell, for example. Setting filters to zero, which is basically what we're talking about here, is going to completely white out your scope. You're going to see EVERYTHING that sends returns in your frequency band. That's going to include terrain, ground vehicles, buildings, possibly weather features, birds, RC planes, spurious bullshit that can't be correlated to anything....and you're going to see a snapshot of it every X seconds, depending on your specific system. Thousands of returns on every sweep. They have to be analyzed, compared to previous sweeps to try and get headings and speeds, maybe altitudes. Processing is obviously an enormous problem for something like that...it's going to take so long to process that there will be a noticeable delay before you ever see the data, if your system even has the capability (to put this in perspective, the AWACS computer already filters a ton of poo poo and the computer STILL crashes all the goddamn time). But when you've got 12,000 dots of roughly the same RCS and a sweep rate of say, 6 rpm, how the hell are you going to actually track them? You're not guaranteed to get a return on every contact on every sweep, and most of them are going to maneuver multiple times between sweeps. Good luck figuring out which is which. On top of that there could be literally HUNDREDS inside your res cell at any given time! The longer the range, the worse that problem gets. E: VVV That's awesome. EM interference was a big issue for us, one of my jobs was building a comm plan for ~20 radios and most of the antennae are spaced about 4 feet apart and capable of burning each other to cinders. Godholio fucked around with this message at 02:01 on May 13, 2015 |
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May 13, 2015 01:50
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Yeah I know it's a thing. A professor at my school did research related to antenna interference patterns with USN grants. I had the project described to me by the professor since I was looking kinda to grad school and met the always critical NOFORN requirement (nothing was classified). In one of these threads I posted something along the lines of "Antennas of different frequencies in close proximity can cause a lot of issues even if transmitting and receiving on very different bands. For an example a British destroyer hit by an Exocet during the Falklands war was taken by surprise because it needed its radar off during satellite uplinks. This is a particularly nasty because *redacted* always interferes with *redacted*..." Or something the *redacted*s seemed to make a decent joke. loving Grover PM'd me asking if I had a SIPR account.  This just confirmed to me that anyone that thinks EM fields stuff is fun is literally insane.
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May 13, 2015 01:56
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Duke Chin posted:Why did they have to put their plane down? Engine flameout. They were dropping from 8kf to 500 feet for their bingo run over the SAM sites on the way back to base. One lost his engine during descent and just barely made it to the strip. Had it happened 30 seconds later, he'd have been landing among mesquite beams that are often over ten or fifteen feet tall. We didn't know if they'd made it til we got a text with the picture when we were about 2/3 of the trip to the last known radar contact going about 100mph down the highway, because the rest of the flight didn't have the fuel to set up an on scene commander.
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May 13, 2015 01:58
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Godholio posted:You're not going to get a hit on every bird, every sweep. Keep in mind these radars aren't just pointing at one spot either, they're sweeping 360 or back-and-forth. Good luck keeping track of which loving sparrow is which. I know you know this, but come on, that's not how all radar works.
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May 13, 2015 01:59
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Forums Terrorist posted:Oh yeah. poo poo, given how good GPGPUs are at this sort of thing the US should be putting export controls on nvidia by now The Tesla's ARE on an export ban, but it doesn't really stop them in most cases.
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May 13, 2015 02:00
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mlmp08 posted:I know you know this, but come on, that's not how all radar works.
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May 13, 2015 02:02
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One simple trick stealth pilots hate!
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May 13, 2015 02:04
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Godholio posted:You're not going to get a hit on every bird, every sweep. Keep in mind these radars aren't just pointing at one spot either, they're sweeping 360 or back-and-forth. Good luck keeping track of which loving sparrow is which. Yes that's why it won't work with a traditional search radar. Are there alternatives to a traditional search radar with modern semiconductors? I'm sure a fuckton of money is being thrown at that one.
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May 13, 2015 02:08
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CharlesM posted:One simple trick stealth pilots hate! It's called an IR camera. Modern IR cameras and computers are quite good.
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May 13, 2015 02:10
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CharlesM posted:One simple trick stealth pilots hate! This needs to be a duffleblog thing like, yesterday... Complete with 10 pages of click-throughs.
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May 13, 2015 02:34
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Godholio posted:I'm sticking to search radars, since that's where this conversation came from, and most of those types are mechanically scanned. For the rest of us lurkers, what are the advantages of AESA vs mechanical scan (within opsec limits)?
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May 13, 2015 02:36
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bitcoin bastard posted:For the rest of us lurkers, what are the advantages of AESA vs mechanical scan (within opsec limits)? It doesn't have to spin around to scan a portion of the sky and thus the refresh rate isn't limited by some mechanical motor, for one. The field of view on a phased array radar is something like 120° IIRC.
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May 13, 2015 02:59
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bennyfactor posted:It doesn't have to spin around to scan a portion of the sky and thus the refresh rate isn't limited by some mechanical motor, for one. The field of view on a phased array radar is something like 120° IIRC. You can kind of think of an AESA as hundreds to thousands little tiny radars which each have a very narrow width. They do move though, think of it as shining a bunch of little laser pointers in a known pattern as opposed to a strobe light.. 120 degrees is indeed the maximum an AESA or any other planar array can see.
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May 13, 2015 03:04
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Godholio posted:You're not going to get a hit on every bird, every sweep. Keep in mind these radars aren't just pointing at one spot either, they're sweeping 360 or back-and-forth. Good luck keeping track of which loving sparrow is which. This is trivial for a Blue Gene, fyi.
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May 13, 2015 03:17
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bitcoin bastard posted:For the rest of us lurkers, what are the advantages of AESA vs mechanical scan (within opsec limits)? A mechanically scanned radar literally moves an array around and aims it at stuff. The most standard version could be those big rotating search versions, but here's a picture of an AN/APG-65, which was used in F-18s. It actually tilts about and takes a considerable amount of time to scan the full area in front of the aircraft. Yay moving parts to fail!  An AESA radar can spin, but when it does it is spinning around a typically flat panel that has the ability to individually steer each and every little beam of energy to wherever it wants to. This means that you can have a rotating AESA radar rotating very quickly, and always put a bunch of focus beams along ridgelines to catch cresting aircraft, low flying aircraft, and cruise missiles while also looking elsewhere in the sky. AESA can typically get better fidelity, is more resistant to jamming, can choose not to emit at certain areas very accurately while still maintaining track and search functions in other areas, and can do multimode like simultaneous air and ground tracking than mechanically scanned radars. They are also stupendously fast. If a mechanical radar sees a blip, it doesn't really get a chance to confirm that blip until the next time it physically looks in that area. An AESA can catch a blip and then almost instantly have confirmation pinpoint emissions to verify whether or not that blip was erroneous or even what that blip actually is. Some AESA can do rad poo poo like synthetic aperture radar (SAR). SAR can be used not just for seeing things in bad weather or through clouds, but for figuring out if targets are moving or not. A SAR image:  Some AESA radars can even modulate their waveforms such that they can actually be used offensively in electronic warfare. AESA is pretty nuts. It's a huge upgrade over PESA, and it makes mechanical scanning look like tinkertoys. Here's a cheesy video about the F-35s AESA. https://www.youtube.com/watch?v=hzDke56vMiU
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May 13, 2015 03:18
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Forums Terrorist posted:This is trivial for a Blue Gene, fyi. The real problem is the 6 rpm part not the computer part. All the RANSAC runs in the world won't help the correspondence problem if your data is sampled too infrequently.
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May 13, 2015 03:19
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Fair enough. It's just that my university has ties with the Low Frequency Array telescope and that's almost exactly what they're doing. The next innovation in IADS is going to be giant supercomputer bunkers processing data from multiple radars using giant fiber-optic trunks, obviously.
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May 13, 2015 03:22
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Forums Terrorist posted:The next innovation in IADS is going to be giant supercomputer bunkers processing data from multiple radars using giant fiber-optic trunks, obviously. if you think the future of IADS is obviously large, fixed structures.
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May 13, 2015 03:34
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Forums Terrorist posted:The next innovation in IADS is going to be giant supercomputer bunkers processing data from multiple radars using giant fiber-optic trunks, obviously. A semi-automated ground environment, if you will?
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May 13, 2015 03:39
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Everything old is new again. 
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May 13, 2015 03:43
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Forums Terrorist posted:Everything old is new again. Or you have no idea what you're talking about, like usual.
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May 13, 2015 03:47
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Something else to remember about the F-22; people always comment on its defensive stealth and overlook the APG-77 being probably the most capable radar ever put on an airplane that isn't the size of a 707. 120Ds are supposedly in active service now too (no idea if they are with the 22 though). Mazz fucked around with this message at 04:05 on May 13, 2015 |
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May 13, 2015 03:52
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Forums Terrorist posted:Fair enough. It's just that my university has ties with the Low Frequency Array telescope and that's almost exactly what they're doing. The crew's tablets might have enough horse power these days.
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May 13, 2015 04:09
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Mazz posted:Something else to remember about the F-22; people always comment on its defensive stealth and overlook the APG-77 being probably the most capable radar ever put on an airplane that isn't the size of a 707. If they're not, someone needs to be loving strung up, even in this day and age of 5-sided stupidity. The APG-77 is a lot better at a lot of things than an APY-1/-2. The versatility is just crazy. And I'm still not sure if this was a seriouspost or not: Forums Terrorist posted:
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May 13, 2015 04:47
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Let me ask a question that fits into the previous topic seamlessly: how much do you love flying boats? If the answer is "a hella lot" then this is the site for you. It has a catalog of design plans for flying boats. Reviews of books, entirely about flying boats. Color charts for flying boat painting covering all flying boats during their heyday. A index of out of print articles on flying boats. Walk arounds of flying boats. Another comprehensive index of models of flying boats. A index of flying boat cut-aways. Dare I say it, it's pretty aeronautically insane, and my hat is off to whomever is maintaining this site.
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May 13, 2015 06:09
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Previa_fun posted:Aeronautical Insanity: These assholes from maintenance move everything. What poo poo have they done? I actually chuckled when this line came up when I was watching Charlie Victor Romeo the other day. mlmp08 posted:If you want more details see your local recruiting office and be able to hold a clearance. Someone please do this and then report back with where you actually end up, I could use a laugh. mlmp08 posted:A SAR image: Lynx SAR is one of the few things GA-ASI makes that doesn't loving suck. It can do GMTI and Maritime Search along with a few other cool things, and the whole package is about 80 lbs. Maybe they need to transfer some of their surveillance division engineers over to the aircraft side of things. Mazz posted:120Ds are supposedly in active service now too (no idea if they are with the 22 though). Godholio posted:If they're not, someone needs to be loving strung up, even in this day and age of 5-sided stupidity. The APG-77 is a lot better at a lot of things than an APY-1/-2. The versatility is just crazy. The initial deployment was apparently on some SHornets. And no, shouldn't be on Raptors yet. AIM-120D and AIM-9X don't get integrated until Increment 3.2B...it's a separate MDAP from the baseline PoR with IOT&E scheduled for FY17. So expect fielding around FY18 maybe? lol yeah right it's going to be more like FY19 or FY20. This is an upgrade/"program" that started development work in 2008, became its own MDAP in 2013, and still isn't scheduled for IOT&E until 2017. So yeah, looks like there's a lot of stringing up that you'll be doing.
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May 13, 2015 06:10
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iyaayas01 posted:it's a separate MDAP from the baseline PoR with IOT&E scheduled for FY17 lol
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May 13, 2015 06:25
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yeah I was going to say, the fact that I wrote that sentence and at a glance I completely understand everything in it means I should probably go kill myself
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May 13, 2015 06:30
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iyaayas01 posted:yeah I was going to say, the fact that I wrote that sentence and at a glance I completely understand everything in it means I should probably go kill myself I'm poking fun. My wife just shouts "Airspace!" any time I get caught up talking about aviation/work related things in technical detail. It's her codeword for "shut up."
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May 13, 2015 06:34
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Found these pictures of the NASA XC-142 online. Was this thing the precursor to the osprey?   lol accident prone, love the expression of the guy in the back.   It's amazingly stubby looking, and is that a tiny horizontal propeller on the tail sting? 
GlassEye-Boy fucked around with this message at 08:03 on May 13, 2015 |
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May 13, 2015 08:00
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