8 ms·

How does a fighter jet lock onto and keep track of an enemy aircraft? (2013)

251 points by KhalilK 12y ago

Someone1234 12y ago
Good response, worth the read. Heck the response alone could justify their own article. As an aside: I hate quora' site design so much I have blacklisted it using Google Personal Blocklist. Somehow I dislike it more than Experts Exchange (which is also blacklisted), it is just super cluttered with nonsense, rolls into the comments section without warning and rarely offers good content (see Experts Exchange again). That being said Yahoo! Answers also rarely has good content but at least with Yahoo! Answers you can determine that with a glance. You visit the page and you can see the answer (or lack of answer). So Yahoo! Answers remains in my search results, Quora and Expert Exchange have been vanished indefinitely. PS - Quora also likes to spawn pop ups whenever you click anywhere on the page for no real reason (just asks for your Quora login details). For someone who randomly highlights blocks of text while reading this is pure hell...
- click170 12y ago
  I remember you used to see experts exchange or the like come up in search results and you could block it right there, in your search results without having to go to a separate page. Since they've hidden it, I honestly thought they'd removed the ability to block websites. Thanks for letting me know I just have to hunt for it. I wonder why they removed that option from search results?
  - infogulch 12y ago
    No the option is completely gone, not just hidden. You have to use an extension (which is what Google Personal Blocklist is).
    - toomuchtodo 12y ago
      Pesonal Blocklist Extension: https://chrome.google.com/webstore/detail/personal-blocklist-by-goo/nolijncfnkgaikbjbdaogikpmpbdcdef https://chrome.google.com/webstore/detail/personal-blocklist...
  - aragot 12y ago
    Same problem here. To dodge w3schools I resorted to writing an /etc/hosts local dns entry, so I would never open it even by mistake.
    - bubble_boi 12y ago
      Browsers should block this by default :) Although www.w3fools.com has softened its stance.
- w1ntermute 12y ago
  > Somehow I dislike it more than Experts Exchange Someone needs to make a Stack Overflow to Quora's Experts Exchange (preferably by just using the Stack Overflow codebase/framework).
  - readerrrr 12y ago
    Is is called Stack Exchange. They don't cover all the topics, but the new sub-sites are being created gradually when demand is made. This one would fit into http://aviation.stackexchange.com/ http://aviation.stackexchange.com/.
- sp332 12y ago
  This one got reposted to Gizmodo, with a saner interface. http://gizmodo.com/how-fighter-jets-lock-on-and-how-the-targets-know-1644871272 http://gizmodo.com/how-fighter-jets-lock-on-and-how-the-targ...
  - dang 12y ago
    Thanks. We changed to that from http://www.quora.com/How-does-a-fighter-jet-lock-onto-and-keep-track-of-an-enemy-aircraft?share=1 http://www.quora.com/How-does-a-fighter-jet-lock-onto-and-ke... since there were so many complaints about the latter.
    - radmuzom 12y ago
      So the average bastard who reads Hacker News still gets to read the content? Your hypocrisy is just amazing.
      - dang 12y ago
        I'm having trouble parsing this. What is the problem, exactly?
        radmuzom 12y ago
        Well, given that the people here seem to have extreme hatred for Quora, they should not be visiting the site or do it on the terms set by Quora. I find it extremely hypocritical that they would want to read extremely interesting content which is often available there. Given that the original link was there in Quora, I don't see any reason why it should be changed - if people find it bad, they should not click the link or flag it so that it disappears. Apologies for the abusive word used.
    - dangelo 12y ago
      The unusual number of complaints on this thread were actually because of a bug causing a bad experience. This was our fault and it has been fixed. We don't mind the change of link - we just want knowledge shared on Quora to get to as many people as possible and we don't mind if it happens on other sites. But I wanted to let you guys know that this was a bug and the behavior is back to normal (nothing with share=1 will ever require viewers to sign in / trigger this level of complaints). There can be so much negativity here that it can be hard to tell the difference between general hate (as radmuzom suspected) and a real problem, but in this case it was a real problem.
- nether 12y ago
  Holy shit, without fail the top comment on a Quora story is a rant about their design. Get over it. Don't click if you don't like it.
  - radmuzom 12y ago
    So true. And upvoted - Quora is one of my finest discoveries in the last two years. It has taught me immensely about various cultures around the world, and while opinion should always be taken with a grain of salt there are enough "factual" answers too. They are also a brilliant engineering company, and have some of the best web-based tools available to those who are asking questions and providing answers. No other site - I repeat, no other site including StackExchange provides as much functionality as Quora. The only downside is that they are sometimes a bit slow. For a forum who talks about free market at the drop of a hat, and tends to defend Amazon in every discussion; my message to get Hacker News is - GET LOST!! We are happy with the real name policy and we are happy to log in to browse the site. If you don't like it, don't use it. Good riddance.
- sanderjd 12y ago
  Which part is the nonsense? The stuff on the sides? What do you mean by "rolls into the comments section without warning"? (Honestly curious.) I think the content is often pretty good! YMMV I guess.
  - bennettfeely 12y ago
    I really don't like the typography. In one page you'll find serif, sans-serif, all-caps, bolded, italicized, black links, blue buttons, green buttons, barely visible gray links.. it's a mess. Every revision they make to the home page (top stories) feed seems like a step backward in readability. The content is usually good but it's still annoying that Quora impedes you from sharing it with others that aren't also on Quora.
- smegel 12y ago
  > That being said Yahoo! Answers also rarely has good content I would go even further and say it is the spiritual successor to YouTube comments before they were G-plussed.
- dangelo 12y ago
  FWIW the "spawn pop ups whenever you click anywhere on the page" was a bug that was fixed.
chollida1 12y ago
Meta Note I'm not sure if its the software or the OP who added the "?share=1" parameter but thank you for including it in the link. The flag makes reading quora possible. If HN doesn't add this parameter by default I think it would be a worth while upgrade to the site. Lots of great content is locked in quora otherwise.
- readerrrr 12y ago
  Since quora has problems in the money department, how is their competitor Stack Exchange maintaining profit?
  - kaoD 12y ago
    Probably not being obnoxious to their potential users.
  - serf 12y ago
    I don't know any numbers, but it seems as if Stack Exchange is far more popular, especially as an information database for employees and students. Quora has the opportunity to do the same, but I think the specific stack exchange communities offer a better partition between topics. Quora does it's best to show you targetted questions/comments, whereas StackExchange sites just throw you wherever you showed up (which, if by search, is usually a better choice) A good example : I once answered a fringe question about the Dalai Lama on Quora, now many of the questions i'm tasked with giving answers to are spiritual in nature, and of absolutely no interest to me. It's the same search bubble problem that YouTube/Google runs into occasionally. Things like that make me prefer more 'basic' sites like StackExchange networks.
  - morgante 12y ago
    Stack Exchange made the brilliant move of having disparate communities with a defined (and passionate) audience for each. This makes selling targeted advertising much easier. Ex. Stack Overflow is probably one of the best places to reach developers with job ads—hence they can charge a lot more for that than generic display ads. This is all pure speculation, but I wouldn't be surprised if Stack Exchange's RPU would be 10x Quora's.
krat0sprakhar 12y ago
Off Topic: Man! Reading this answer so makes me want to play those FlightSim games of the yesteryears like Apache Havoc, Commanche, Jane's F/A 18 Hornet etc etc. Does anyone have any suggestions for a modern Flight Sim game? Thanks!
- serf 12y ago
  I don't know much about combat sims, but I have a blast with X-Plane. It's highly realistic and can practically scale to any performance computer. It has some combat-sim aspects, but I haven't played with that stuff enough to comment. Flying is tough enough for me without the weapons ;)
- Gracana 12y ago
  The DCS sims are some of the best around right now. Check out DCS: A-10C Warthog, I think it's one of the latest releases. https://www.digitalcombatsimulator.com/en/products/warthog/ https://www.digitalcombatsimulator.com/en/products/warthog/
- shiftpgdn 12y ago
  GOG.com has most of those games with a modern windows installer. They're still good fun. :)
- chrisan 12y ago
  Commanche was great. Strike Commander with a full Thrustmaster setup back in the day was epic. Games to keep an eye on (if you like combat) http://www.polygon.com/2014/6/9/5791924/e3-2014-marks-the-return-of-the-flight-sim-genre http://www.polygon.com/2014/6/9/5791924/e3-2014-marks-the-re... Been out of games for a while, but looking forward to Oculus and whatever today's Thrustmaster equivalent is :)
  - the_af 12y ago
    For being a "Wing Commander"-like game, Strike Commander was surprisingly good and detailed. The manual was pretty interesting, with lots of information similar to the Quora answer. The hardcore side of combat flightsim gaming for me was Su-27 Flanker (http://www.mobygames.com/game/su-27-flanker http://www.mobygames.com/game/su-27-flanker), published by SSI. So hardcore I never actually managed to complete a full mission! It was a bit dry, without any campaigns or any kind of career tracking, but man was it detailed! It made me fall in love with the real-life Flanker. And of course, Falcon 3.0 by Spectrum Holobyte. Another awesome flightsim I spent a lot of time with but never managed to complete a single mission with. It was obvious this sim was a work of love.
IgorPartola 12y ago
So why don't they include two radars, one for sweeps and one for tracking? I know, I know, weight, power, etc. At the same time, isn't that the obvious answer?
- theoh 12y ago
  How is it an obvious solution if it is not practical? The electronically-scanned radars mentioned in the second answer can easily divide their time between the tasks (no mechanically-constrained dish to sweep) but there is definitely no space for two radar systems in the nose of a fighter.
  - jlas 12y ago
    Besides space I think having two radars might cause interference that would be difficult to filter out.
- trhway 12y ago
  as other commenter said ESA radars do great simultaneously scanning and tracking, with modern radars - more than 1 target simultaneously. The 2nd radar may be employed for the rear sphere like in that rear "stinger" http://www.airforceworld.com/bomber/eng/su34-fighter-bomber-sukhoi-russia-1.htm http://www.airforceworld.com/bomber/eng/su34-fighter-bomber-...
- _djo_ 12y ago
  No space. Take a look at this image, it's the standard AN/APG-63 on an F-15C fighter aircraft: http://commons.wikimedia.org/wiki/File:APG-63_radar_of_F-15_1985.JPEG http://commons.wikimedia.org/wiki/File:APG-63_radar_of_F-15_... Note how the radar's processing units and dish take up the entirety of the aircraft's nose and how large the system is compared to the technician working on it. There simply isn't enough space to add another radar. Nor would it make sense to split that into two smaller radars, as the size of the dish and processing units is strongly linked to its power and range. That's one reason larger aircraft like the F-15, F-14 and Su-27 have longer-ranged and more powerful radars than smaller fighter aircraft. This track vs scan limitation is removed by Active Electronically Scanned Array (AESA) radars such as this AN/APG-63(V)2 retrofitted to a USAF F-15C: http://www.pacaf.af.mil/shared/media/photodb/photos/070720-F-9999J-001.jpg http://www.pacaf.af.mil/shared/media/photodb/photos/070720-F... Rather than having a mechanically-slaved reflective dish, an AESA radar has hundreds of Transmit/Receive Modules (TRMs) each capable of acting like a tiny radar dish by transmitting or receiving on its own frequency and being steered its own direction. So now, rather than having the radar dish jump between track and scan at rapid intervals, the system can just dedicate a few hundred of the AESA TRMs to tracking one or more targets while letting the remainder continue sweeping the skies. There's no limitation on azimuth because each TRM can be individually steered. So in short, the answer is that the latest fighter aircraft don't have two radars, they have hundreds or thousands of tiny radars that can work together in a whole bunch of useful combinations. Edit: Replaced initial image with a Wiki Commons link that doesn't have linking issues.
jlas 12y ago
Another interesting aspect is the Lock-On detection of the enemy aircraft. Aircraft are able to identify when they're being tracked by other aircraft or homing missles. [1] http://en.wikipedia.org/wiki/Radar_warning_receiver http://en.wikipedia.org/wiki/Radar_warning_receiver
- lucb1e 12y ago
  like mentioned in the answer..?
hueving 12y ago
Is there any way to view the rest of the answer hidden behind the "more" link without signing up for an account?
- existencebox 12y ago
  I would also appreciate this. I was finding the article very interesting but the wall killed it for me.
- el_benhameen 12y ago
  I usually just open dev tools and delete the div that contains the modal dialog and gray-out background (its ID is along the lines of "Modal_signup_wrapper"). You still won't be able to read past the first answer, but at least you'll get all of that answer's content.
- d_k_f 12y ago
  Try adding "?share=1" to the URL, that should do the trick.
ufmace 12y ago
Related anecdote - I worked with a coder a while back who was a naval aviator before he went back to school, flying carrier-based transports. I asked him once about whether he would have wanted to fly fighters instead, and he said that just flying transports was already a huge amount of work, as far as flight plans, training, practice, and such. Flying fighters apparently involved doing all of that same work, plus a bunch more for weapons, tactics, etc, so those guys never had any free time. Apparently, flying fighters wasn't nearly as fun as it sounds.
- AceJohnny2 12y ago
  > Apparently, flying fighters wasn't nearly as fun as it sounds. Hm. I figure the glory you get from being a fighter pilot is one of the perks, so they might as well milk that for all it's worth. My point is that it's interesting to note the professions that seem more glorious than they actually are, and beware those who sell themselves or the job based on that glory: it's an illusion.
- bkohlmann 12y ago
  believe me, flying fighters really is as much fun as it sounds. It is more work than the transport guys, but you get out what you put in. its all worth it coming in for a 450 knot overhead at 600', pulling six g's in the break, then catching the three-wire aboard the carrier.
  - informatimago 12y ago
    Yes, it looks like it's fun: https://www.youtube.com/watch?v=1wEURyjB3Lc https://www.youtube.com/watch?v=1wEURyjB3Lc https://www.youtube.com/watch?v=sH7TiA58UzQ https://www.youtube.com/watch?v=sH7TiA58UzQ ;-)
  - KhalilK 12y ago
    Indeed. https://www.youtube.com/watch?v=HEe3xfWfkG8 https://www.youtube.com/watch?v=HEe3xfWfkG8 I am curious to know how such footage is shot.
  - swah 12y ago
OldSchool 12y ago
Hmmm, I was kind of hoping for an explanation of how the control system determines how to modify the highly directional antenna's orientation to continue to maximally "illuminate" the target once it's been selected from a general scan. Can anyone describe the solution to this? Example idea: Once selected for "lock," the antenna scans in small circles and migrates its central point toward the point on the scanned circle that provides the strongest return, allowing for variation due to noise sources.
- ChuckMcM 12y ago
  There is a book on it[1]. But suffice it to say that the radar is computing an "exit vector" when the target it moving away from center and applying a correction to the pointer. I built a similar system with LEDs when building a tracking system for two moving robots. In my case I used a parabolic dish (a solar cigarette lighter) and a line of LEDs (bar graph display) as detectors rather than lights. Since the target robot and the pursuing robot had their beacon and search dish in the same plane I could reduce the problem to a managable bit of 2D geometry. As the signal went off axis you could turn the robot to re-align by applying the opposite rotation. [1] "Multiple Target Tracking with Radar Applications" - Sam Blackman (http://books.google.com/books?id=Ag9TAAAAMAAJ&q=tracking+multiple+targets+with+radar&dq=tracking+multiple+targets+with+radar&hl=en&sa=X&ei=VVk4VPiNLsnwoAS4rICoCw&ved=0CC0Q6AEwAA http://books.google.com/books?id=Ag9TAAAAMAAJ&q=tracking+mul...)
  - OldSchool 12y ago
    Thanks for the thoughtful reply and reference!
- toomuchtodo 12y ago
  Are you asking if the antenna gets moved to illuminate the target once acquired? I apologize if I misunderstood. If that's the case, the antenna is a solid state phased array; no movement is required. Mobile communications (cellular and satellite) spot beams work under the same principal. http://www.northropgrumman.com/Capabilities/MESA/Documents/aesa_techpaper.pdf http://www.northropgrumman.com/Capabilities/MESA/Documents/a...
deleted 12y ago
[deleted]
platz 12y ago
After playing something like Falcon BMS you'll have all these radars memorized. https://www.youtube.com/watch?v=uU3pmXvnc0k&hd=1 https://www.youtube.com/watch?v=uU3pmXvnc0k&hd=1 It acutally makes the sim quite fun to play, although you do have to get past that learning curve. I think for me it was the learning part that was kind of fun too
- Perseids 12y ago
  The radar discussion in the video is pretty good itself. It begins at 30min 31sec: http://youtu.be/uU3pmXvnc0k?t=30m31s http://youtu.be/uU3pmXvnc0k?t=30m31s .
reduce 12y ago
The system has not performed "a lock on the target", at least not in the way that the language leads you to believe. The tool is making a prediction, that within a certain level of confidence, and given the present parameters, that firing the missile will result in the neutralization of the target. There's growing number of ways, both active and passive, that targets can be tracked or future positions predicted. One of the answers on that page hints at this, the other answer is misleading and often not how it's done in many modern systems. Source: engineered parts of these systems before.
- berkut 12y ago
  The radar and weapon control systems are "locked on" to from the aircraft's perspective - I don't really understand what you're talking about... A particular target has been identified, it is being tracked (maybe at the expense of scanning for other targets if its an older system, probably with track-while-scan otherwise), and based on this updates are being sent to the missile in order to control its initial trajectory when it gets launched to point it in the correct direction.
ibisum 12y ago
Upon reading of RWR and its delights, at least one part of me, the techno-dweeb, goes "weeeh!" .. Another part, more of a hippy tree-hugger, goes "wish we were using this to figure out where to drop the water/medicine/books instead of BOOMB devices" .. I mean, seriously. Tell us where to drop the books, and BOOM there it is: how it should be.
- caf 12y ago
  You might be interested in the UAV Challenge: http://www.uavoutbackchallenge.com.au/ http://www.uavoutbackchallenge.com.au/
AYBABTME 12y ago
This was a great read until I reached the truncated bottom of the post. God I hate Quora. There's the `share=1` flag but still, the end of the article is truncated and you're asked to login. Quora wouldn't piss me off so much if they were not so annoying about me logging in and linking a social account, if they didn't post crap from my friend's facebook account who do have an account, send me spam about whatever people I know might have done (or not done) on their platform. This is trying to gather users by pissing them off. Likely I'd have created an account since if it weren't for their aggressive behavior.
- KhalilK 12y ago
  That's odd. On the page with the signup box look for the id "__w2_LG4FatW_modal_signup_wrapper" and delete the whole div, that'll get rid of the box allowing to you to continue reading the top answer but not the others.
- dangelo 12y ago
  The truncation was a bug that was fixed. Sorry about that.
Rapzid 12y ago
Interesting(I didn't read the whole article because I'm not logging into Quora). I wonder what the state of the art is? Certainly we have tech now to get all the info on all the aircrafts? I would think that software could be employed to fill in the gaps and extrapolate the info at the least. What with 3d video tracking and the like at the levels they are at today.

251 points by KhalilK 12y ago

Good response, worth the read. Heck the response alone could justify their own article. As an aside: I hate quora' site design so much I have blacklisted it using Google Personal Blocklist. Somehow I dislike it more than Experts Exchange (which is also blacklisted), it is just super cluttered with nonsense, rolls into the comments section without warning and rarely offers good content (see Experts Exchange again). That being said Yahoo! Answers also rarely has good content but at least with Yahoo! Answers you can determine that with a glance. You visit the page and you can see the answer (or lack of answer). So Yahoo! Answers remains in my search results, Quora and Expert Exchange have been vanished indefinitely. PS - Quora also likes to spawn pop ups whenever you click anywhere on the page for no real reason (just asks for your Quora login details). For someone who randomly highlights blocks of text while reading this is pure hell...

click170 12y ago
I remember you used to see experts exchange or the like come up in search results and you could block it right there, in your search results without having to go to a separate page. Since they've hidden it, I honestly thought they'd removed the ability to block websites. Thanks for letting me know I just have to hunt for it. I wonder why they removed that option from search results?
- infogulch 12y ago
  No the option is completely gone, not just hidden. You have to use an extension (which is what Google Personal Blocklist is).
  - toomuchtodo 12y ago
    Pesonal Blocklist Extension: https://chrome.google.com/webstore/detail/personal-blocklist-by-goo/nolijncfnkgaikbjbdaogikpmpbdcdef https://chrome.google.com/webstore/detail/personal-blocklist...
- aragot 12y ago
  Same problem here. To dodge w3schools I resorted to writing an /etc/hosts local dns entry, so I would never open it even by mistake.
  - bubble_boi 12y ago
    Browsers should block this by default :) Although www.w3fools.com has softened its stance.
w1ntermute 12y ago
> Somehow I dislike it more than Experts Exchange Someone needs to make a Stack Overflow to Quora's Experts Exchange (preferably by just using the Stack Overflow codebase/framework).
- readerrrr 12y ago
  Is is called Stack Exchange. They don't cover all the topics, but the new sub-sites are being created gradually when demand is made. This one would fit into http://aviation.stackexchange.com/ http://aviation.stackexchange.com/.
sp332 12y ago
This one got reposted to Gizmodo, with a saner interface. http://gizmodo.com/how-fighter-jets-lock-on-and-how-the-targets-know-1644871272 http://gizmodo.com/how-fighter-jets-lock-on-and-how-the-targ...
- dang 12y ago
  Thanks. We changed to that from http://www.quora.com/How-does-a-fighter-jet-lock-onto-and-keep-track-of-an-enemy-aircraft?share=1 http://www.quora.com/How-does-a-fighter-jet-lock-onto-and-ke... since there were so many complaints about the latter.
  - radmuzom 12y ago
    So the average bastard who reads Hacker News still gets to read the content? Your hypocrisy is just amazing.
    - dang 12y ago
      I'm having trouble parsing this. What is the problem, exactly?
      - radmuzom 12y ago
        Well, given that the people here seem to have extreme hatred for Quora, they should not be visiting the site or do it on the terms set by Quora. I find it extremely hypocritical that they would want to read extremely interesting content which is often available there. Given that the original link was there in Quora, I don't see any reason why it should be changed - if people find it bad, they should not click the link or flag it so that it disappears. Apologies for the abusive word used.
  - dangelo 12y ago
    The unusual number of complaints on this thread were actually because of a bug causing a bad experience. This was our fault and it has been fixed. We don't mind the change of link - we just want knowledge shared on Quora to get to as many people as possible and we don't mind if it happens on other sites. But I wanted to let you guys know that this was a bug and the behavior is back to normal (nothing with share=1 will ever require viewers to sign in / trigger this level of complaints). There can be so much negativity here that it can be hard to tell the difference between general hate (as radmuzom suspected) and a real problem, but in this case it was a real problem.
nether 12y ago
Holy shit, without fail the top comment on a Quora story is a rant about their design. Get over it. Don't click if you don't like it.
- radmuzom 12y ago
  So true. And upvoted - Quora is one of my finest discoveries in the last two years. It has taught me immensely about various cultures around the world, and while opinion should always be taken with a grain of salt there are enough "factual" answers too. They are also a brilliant engineering company, and have some of the best web-based tools available to those who are asking questions and providing answers. No other site - I repeat, no other site including StackExchange provides as much functionality as Quora. The only downside is that they are sometimes a bit slow. For a forum who talks about free market at the drop of a hat, and tends to defend Amazon in every discussion; my message to get Hacker News is - GET LOST!! We are happy with the real name policy and we are happy to log in to browse the site. If you don't like it, don't use it. Good riddance.
sanderjd 12y ago
Which part is the nonsense? The stuff on the sides? What do you mean by "rolls into the comments section without warning"? (Honestly curious.) I think the content is often pretty good! YMMV I guess.
- bennettfeely 12y ago
  I really don't like the typography. In one page you'll find serif, sans-serif, all-caps, bolded, italicized, black links, blue buttons, green buttons, barely visible gray links.. it's a mess. Every revision they make to the home page (top stories) feed seems like a step backward in readability. The content is usually good but it's still annoying that Quora impedes you from sharing it with others that aren't also on Quora.
smegel 12y ago
> That being said Yahoo! Answers also rarely has good content I would go even further and say it is the spiritual successor to YouTube comments before they were G-plussed.
dangelo 12y ago
FWIW the "spawn pop ups whenever you click anywhere on the page" was a bug that was fixed.

chollida1 12y ago

Meta Note I'm not sure if its the software or the OP who added the "?share=1" parameter but thank you for including it in the link. The flag makes reading quora possible. If HN doesn't add this parameter by default I think it would be a worth while upgrade to the site. Lots of great content is locked in quora otherwise.

readerrrr 12y ago
Since quora has problems in the money department, how is their competitor Stack Exchange maintaining profit?
- kaoD 12y ago
  Probably not being obnoxious to their potential users.
- serf 12y ago
  I don't know any numbers, but it seems as if Stack Exchange is far more popular, especially as an information database for employees and students. Quora has the opportunity to do the same, but I think the specific stack exchange communities offer a better partition between topics. Quora does it's best to show you targetted questions/comments, whereas StackExchange sites just throw you wherever you showed up (which, if by search, is usually a better choice) A good example : I once answered a fringe question about the Dalai Lama on Quora, now many of the questions i'm tasked with giving answers to are spiritual in nature, and of absolutely no interest to me. It's the same search bubble problem that YouTube/Google runs into occasionally. Things like that make me prefer more 'basic' sites like StackExchange networks.
- morgante 12y ago
  Stack Exchange made the brilliant move of having disparate communities with a defined (and passionate) audience for each. This makes selling targeted advertising much easier. Ex. Stack Overflow is probably one of the best places to reach developers with job ads—hence they can charge a lot more for that than generic display ads. This is all pure speculation, but I wouldn't be surprised if Stack Exchange's RPU would be 10x Quora's.

krat0sprakhar 12y ago

Off Topic: Man! Reading this answer so makes me want to play those FlightSim games of the yesteryears like Apache Havoc, Commanche, Jane's F/A 18 Hornet etc etc. Does anyone have any suggestions for a modern Flight Sim game? Thanks!

serf 12y ago
I don't know much about combat sims, but I have a blast with X-Plane. It's highly realistic and can practically scale to any performance computer. It has some combat-sim aspects, but I haven't played with that stuff enough to comment. Flying is tough enough for me without the weapons ;)
Gracana 12y ago
The DCS sims are some of the best around right now. Check out DCS: A-10C Warthog, I think it's one of the latest releases. https://www.digitalcombatsimulator.com/en/products/warthog/ https://www.digitalcombatsimulator.com/en/products/warthog/
shiftpgdn 12y ago
GOG.com has most of those games with a modern windows installer. They're still good fun. :)
chrisan 12y ago
Commanche was great. Strike Commander with a full Thrustmaster setup back in the day was epic. Games to keep an eye on (if you like combat) http://www.polygon.com/2014/6/9/5791924/e3-2014-marks-the-return-of-the-flight-sim-genre http://www.polygon.com/2014/6/9/5791924/e3-2014-marks-the-re... Been out of games for a while, but looking forward to Oculus and whatever today's Thrustmaster equivalent is :)
- the_af 12y ago
  For being a "Wing Commander"-like game, Strike Commander was surprisingly good and detailed. The manual was pretty interesting, with lots of information similar to the Quora answer. The hardcore side of combat flightsim gaming for me was Su-27 Flanker (http://www.mobygames.com/game/su-27-flanker http://www.mobygames.com/game/su-27-flanker), published by SSI. So hardcore I never actually managed to complete a full mission! It was a bit dry, without any campaigns or any kind of career tracking, but man was it detailed! It made me fall in love with the real-life Flanker. And of course, Falcon 3.0 by Spectrum Holobyte. Another awesome flightsim I spent a lot of time with but never managed to complete a single mission with. It was obvious this sim was a work of love.

IgorPartola 12y ago

So why don't they include two radars, one for sweeps and one for tracking? I know, I know, weight, power, etc. At the same time, isn't that the obvious answer?

theoh 12y ago
How is it an obvious solution if it is not practical? The electronically-scanned radars mentioned in the second answer can easily divide their time between the tasks (no mechanically-constrained dish to sweep) but there is definitely no space for two radar systems in the nose of a fighter.
- jlas 12y ago
  Besides space I think having two radars might cause interference that would be difficult to filter out.
trhway 12y ago
as other commenter said ESA radars do great simultaneously scanning and tracking, with modern radars - more than 1 target simultaneously. The 2nd radar may be employed for the rear sphere like in that rear "stinger" http://www.airforceworld.com/bomber/eng/su34-fighter-bomber-sukhoi-russia-1.htm http://www.airforceworld.com/bomber/eng/su34-fighter-bomber-...
_djo_ 12y ago
No space. Take a look at this image, it's the standard AN/APG-63 on an F-15C fighter aircraft: http://commons.wikimedia.org/wiki/File:APG-63_radar_of_F-15_1985.JPEG http://commons.wikimedia.org/wiki/File:APG-63_radar_of_F-15_... Note how the radar's processing units and dish take up the entirety of the aircraft's nose and how large the system is compared to the technician working on it. There simply isn't enough space to add another radar. Nor would it make sense to split that into two smaller radars, as the size of the dish and processing units is strongly linked to its power and range. That's one reason larger aircraft like the F-15, F-14 and Su-27 have longer-ranged and more powerful radars than smaller fighter aircraft. This track vs scan limitation is removed by Active Electronically Scanned Array (AESA) radars such as this AN/APG-63(V)2 retrofitted to a USAF F-15C: http://www.pacaf.af.mil/shared/media/photodb/photos/070720-F-9999J-001.jpg http://www.pacaf.af.mil/shared/media/photodb/photos/070720-F... Rather than having a mechanically-slaved reflective dish, an AESA radar has hundreds of Transmit/Receive Modules (TRMs) each capable of acting like a tiny radar dish by transmitting or receiving on its own frequency and being steered its own direction. So now, rather than having the radar dish jump between track and scan at rapid intervals, the system can just dedicate a few hundred of the AESA TRMs to tracking one or more targets while letting the remainder continue sweeping the skies. There's no limitation on azimuth because each TRM can be individually steered. So in short, the answer is that the latest fighter aircraft don't have two radars, they have hundreds or thousands of tiny radars that can work together in a whole bunch of useful combinations. Edit: Replaced initial image with a Wiki Commons link that doesn't have linking issues.

jlas 12y ago

Another interesting aspect is the Lock-On detection of the enemy aircraft. Aircraft are able to identify when they're being tracked by other aircraft or homing missles. [1] http://en.wikipedia.org/wiki/Radar_warning_receiver http://en.wikipedia.org/wiki/Radar_warning_receiver

lucb1e 12y ago
like mentioned in the answer..?

hueving 12y ago

Is there any way to view the rest of the answer hidden behind the "more" link without signing up for an account?

existencebox 12y ago
I would also appreciate this. I was finding the article very interesting but the wall killed it for me.
el_benhameen 12y ago
I usually just open dev tools and delete the div that contains the modal dialog and gray-out background (its ID is along the lines of "Modal_signup_wrapper"). You still won't be able to read past the first answer, but at least you'll get all of that answer's content.
d_k_f 12y ago
Try adding "?share=1" to the URL, that should do the trick.

ufmace 12y ago

Related anecdote - I worked with a coder a while back who was a naval aviator before he went back to school, flying carrier-based transports. I asked him once about whether he would have wanted to fly fighters instead, and he said that just flying transports was already a huge amount of work, as far as flight plans, training, practice, and such. Flying fighters apparently involved doing all of that same work, plus a bunch more for weapons, tactics, etc, so those guys never had any free time. Apparently, flying fighters wasn't nearly as fun as it sounds.

AceJohnny2 12y ago
> Apparently, flying fighters wasn't nearly as fun as it sounds. Hm. I figure the glory you get from being a fighter pilot is one of the perks, so they might as well milk that for all it's worth. My point is that it's interesting to note the professions that seem more glorious than they actually are, and beware those who sell themselves or the job based on that glory: it's an illusion.
bkohlmann 12y ago
believe me, flying fighters really is as much fun as it sounds. It is more work than the transport guys, but you get out what you put in. its all worth it coming in for a 450 knot overhead at 600', pulling six g's in the break, then catching the three-wire aboard the carrier.
- informatimago 12y ago
  Yes, it looks like it's fun: https://www.youtube.com/watch?v=1wEURyjB3Lc https://www.youtube.com/watch?v=1wEURyjB3Lc https://www.youtube.com/watch?v=sH7TiA58UzQ https://www.youtube.com/watch?v=sH7TiA58UzQ ;-)
- KhalilK 12y ago
  Indeed. https://www.youtube.com/watch?v=HEe3xfWfkG8 https://www.youtube.com/watch?v=HEe3xfWfkG8 I am curious to know how such footage is shot.
- swah 12y ago

OldSchool 12y ago

Hmmm, I was kind of hoping for an explanation of how the control system determines how to modify the highly directional antenna's orientation to continue to maximally "illuminate" the target once it's been selected from a general scan. Can anyone describe the solution to this? Example idea: Once selected for "lock," the antenna scans in small circles and migrates its central point toward the point on the scanned circle that provides the strongest return, allowing for variation due to noise sources.

ChuckMcM 12y ago
There is a book on it[1]. But suffice it to say that the radar is computing an "exit vector" when the target it moving away from center and applying a correction to the pointer. I built a similar system with LEDs when building a tracking system for two moving robots. In my case I used a parabolic dish (a solar cigarette lighter) and a line of LEDs (bar graph display) as detectors rather than lights. Since the target robot and the pursuing robot had their beacon and search dish in the same plane I could reduce the problem to a managable bit of 2D geometry. As the signal went off axis you could turn the robot to re-align by applying the opposite rotation. [1] "Multiple Target Tracking with Radar Applications" - Sam Blackman (http://books.google.com/books?id=Ag9TAAAAMAAJ&q=tracking+multiple+targets+with+radar&dq=tracking+multiple+targets+with+radar&hl=en&sa=X&ei=VVk4VPiNLsnwoAS4rICoCw&ved=0CC0Q6AEwAA http://books.google.com/books?id=Ag9TAAAAMAAJ&q=tracking+mul...)
- OldSchool 12y ago
  Thanks for the thoughtful reply and reference!
toomuchtodo 12y ago
Are you asking if the antenna gets moved to illuminate the target once acquired? I apologize if I misunderstood. If that's the case, the antenna is a solid state phased array; no movement is required. Mobile communications (cellular and satellite) spot beams work under the same principal. http://www.northropgrumman.com/Capabilities/MESA/Documents/aesa_techpaper.pdf http://www.northropgrumman.com/Capabilities/MESA/Documents/a...

deleted 12y ago

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platz 12y ago

After playing something like Falcon BMS you'll have all these radars memorized. https://www.youtube.com/watch?v=uU3pmXvnc0k&hd=1 https://www.youtube.com/watch?v=uU3pmXvnc0k&hd=1 It acutally makes the sim quite fun to play, although you do have to get past that learning curve. I think for me it was the learning part that was kind of fun too

Perseids 12y ago
The radar discussion in the video is pretty good itself. It begins at 30min 31sec: http://youtu.be/uU3pmXvnc0k?t=30m31s http://youtu.be/uU3pmXvnc0k?t=30m31s .

reduce 12y ago

The system has not performed "a lock on the target", at least not in the way that the language leads you to believe. The tool is making a prediction, that within a certain level of confidence, and given the present parameters, that firing the missile will result in the neutralization of the target. There's growing number of ways, both active and passive, that targets can be tracked or future positions predicted. One of the answers on that page hints at this, the other answer is misleading and often not how it's done in many modern systems. Source: engineered parts of these systems before.

berkut 12y ago
The radar and weapon control systems are "locked on" to from the aircraft's perspective - I don't really understand what you're talking about... A particular target has been identified, it is being tracked (maybe at the expense of scanning for other targets if its an older system, probably with track-while-scan otherwise), and based on this updates are being sent to the missile in order to control its initial trajectory when it gets launched to point it in the correct direction.

ibisum 12y ago

Upon reading of RWR and its delights, at least one part of me, the techno-dweeb, goes "weeeh!" .. Another part, more of a hippy tree-hugger, goes "wish we were using this to figure out where to drop the water/medicine/books instead of BOOMB devices" .. I mean, seriously. Tell us where to drop the books, and BOOM there it is: how it should be.

caf 12y ago
You might be interested in the UAV Challenge: http://www.uavoutbackchallenge.com.au/ http://www.uavoutbackchallenge.com.au/

AYBABTME 12y ago

This was a great read until I reached the truncated bottom of the post. God I hate Quora. There's the `share=1` flag but still, the end of the article is truncated and you're asked to login. Quora wouldn't piss me off so much if they were not so annoying about me logging in and linking a social account, if they didn't post crap from my friend's facebook account who do have an account, send me spam about whatever people I know might have done (or not done) on their platform. This is trying to gather users by pissing them off. Likely I'd have created an account since if it weren't for their aggressive behavior.

KhalilK 12y ago
That's odd. On the page with the signup box look for the id "__w2_LG4FatW_modal_signup_wrapper" and delete the whole div, that'll get rid of the box allowing to you to continue reading the top answer but not the others.
dangelo 12y ago
The truncation was a bug that was fixed. Sorry about that.

Rapzid 12y ago

Interesting(I didn't read the whole article because I'm not logging into Quora). I wonder what the state of the art is? Certainly we have tech now to get all the info on all the aircrafts? I would think that software could be employed to fill in the gaps and extrapolate the info at the least. What with 3d video tracking and the like at the levels they are at today.