[HN Gopher] How fighter jets lock on, and how the targets know (... ___________________________________________________________________ How fighter jets lock on, and how the targets know (2014) Author : ushakov Score : 373 points Date : 2021-06-12 10:34 UTC (12 hours ago) (HTM) web link (www.quora.com) (TXT) w3m dump (www.quora.com) | oehpr wrote: | If you happen to have a VR headset and are looking to play around | with the toys described in the article, I recommend VTOL VR. It | has pretty low system requirements, and takes advantage of VR to | create a virtual hotas (It is much more effective than you would | expect). The physics simulation is, to my understanding, very | good. And everything described in this article is present in the | game to be played around with. | | VTOL VR taught me about "Radar Notching". The article briefly | mentions how radar can actively detect the doppler shift of | targets. If you think about it, the doppler shift of the ground | would be neutral, right? Or roughly the speed of the aircraft. So | lets say you've been locked on by a fighter at high altitude and | they've fired a radar seeker at you. Your backdrop is the ground, | it can pick you out because you're moving so fast. So what you do | is bank your aircraft to fly at a 90 degree angle to the oncoming | missile. Now your doppler shift is the same as the ground and you | blend in, the radar filters out the ground because of it's | expected speed, which is now the relative speed you are moving. | You get "notched out", and the missile will lose track. | t0mas88 wrote: | Radar is also very good at distance measurement so I guess this | won't work for a real life rocket fired at a fighter jet. | Because it's so easy to defeat this trick in the software. | angry_octet wrote: | Notching definitely works, it is used routinely in air | combat. It is more effective at greater range because it's | hard to maintain the same distance to a radar that is closing | on you. | | The principal use is to break missile lock. It's less useful | for disguising position, especially against opponents with | AEW&C and data link. Breaking lock means reducing the doppler | return to below the range gate threshold, and changing | bearing to escape the Kalman filter that is predicting your | position based on prior kinematics. | oehpr wrote: | I'm to understand that tricks like this are much less | effective against more modern A2A missiles, so you might be | right. | sandworm101 wrote: | A missile will generally not care about distance. What | matters is direction/angle. Distance is irrelevant. Just keep | pointing at the target and eventually you will get there, | assuming you are faster. So the direction to the strongest | reflection, or greatest doppler shift, or combination of | both, will suffice to get the missile to the target even | without range data. | nradov wrote: | That was true for earlier radar guided missiles. The latest | ones are smart enough to account for distance and calculate | an energy optimized intercept course rather than just | pointing straight at the target. | [deleted] | sandworm101 wrote: | Missile _systems_. Such complex approaches are calculated | and controlled by the launching platform. A radar-guided | missile will normally not "see" the target on its own | until long after launch, until near endgame. Whether the | actually missile has the brains to make such calculations | is different than whether the entire system has the | ability. | dvtrn wrote: | The missile knows where it is by knowing where it isn't. | raviolo wrote: | For the confused (or to get more confused!): | | https://youtu.be/bZe5J8SVCYQ | avereveard wrote: | Say derivative without saying derivative | ryanmarsh wrote: | By subtracting where it is from where it isn't, or where | it isn't from where it is (whichever is greater), it | obtains a difference, or deviation. | klodolph wrote: | It's been a long time since homing missiles aimed | directly at the target. The AIM-9 Sidewinder entered | service in 1956, and it aimed at where the target _will | be,_ not where it is. | sandworm101 wrote: | Some early IR missiles do aim slightly ahead of the | target's bearing, but they don't really 'know' where they | or the target are located in time and space. It is one | thing to tell a missile to aim 10% to the left of a | target bearing (which isn't simple in 3d space) another | for that missile to understand its relative position. The | early sidewinder used a single IR sensor behind a | spinning reticule made of slots. This wasn't a camera | with multiple pixels. It was one big pixel. The "brain" | would alter the missiles course according to the position | of that spinning reticule and the blinking signal from | the lone sensor. There was no concept of range. At best, | the brain could keep the target at a specific angle. This | was achieved through literally re-drawing the reticule to | include a solid band at the appropriate angle. So long as | the target was behind this dark band the sensor would not | blink and the missile would fly strait. Should the target | move, the blinking would start and the missile would turn | to put it back in the blank/dead zone. | | https://images.app.goo.gl/N3mTpDUeeJW6W7wu9 | wyager wrote: | > Just keep pointing at the target and eventually you will | get there | | Surely they can't use this poor of an optimization | strategy? If the target is moving perpendicular to you, you | want to point slightly ahead of the target so you intercept | them as quickly as possible. | jameshart wrote: | 'Pointing at' in this case means maintaining a constant | bearing to target, with decreasing range. If anything | it's _easier_ for a moving guidance system to achieve | that than to point at the target. | giva wrote: | Link for clarification: | | https://en.wikipedia.org/wiki/Constant_bearing%2C_decreas | ing... | sandworm101 wrote: | Except that, in the case of a missile, you cannot assume | decreasing range. We assume that the missile knows to aim | ahead of the target, but determining which way is ahead | and which behind is tricky. If it is chasing a hotspot, a | single point, getting that wrong means worsening your | approach. A strait/boresight approach might not be ideal | but it avoids the question over which offset is ahead and | which behind the target. | thrill wrote: | Continuously pointing directly at the target tends to | result in the missile being unable to generate the needed | turn rate at the conclusion of the intercept. If the | missile has a large warhead, that might not matter so | much, but air-to-air missiles tend to be small. | jameshart wrote: | If you're a missile seeker, all you have as input is a | two-dimensional forward view of where in your forward | cone the target is - either deflection and azimuth, or x | and y offset - it's like a dot on a scope. Let's assume | cartesian x and y input for simplicity. | | So as you track, you can measure where it is, and how | fast it's apparently moving in those two degrees of | freedom - so you know x, y, dx and dy (and I guess you | know higher degree deltas too). | | To hit it (assuming it's in front of you) _all you need | to do is make control inputs to bring dx and dy to zero_ | - you don 't care what x and y are. If dx and dy are | zero, if you're faster than the thing you're tracking, | you're going to hit it - that's constant bearing, | decreasing range. | | Making control inputs to bring x and y to zero _as well_ | as dx and dy is a harder problem! You need to control | four degrees of freedom to do that. | | And making control inputs just to try to bring x and y to | zero without controlling dx and dy is a good way to miss | the target completely - obviously if you get x and y to 0 | but dx and dy are nonzero, the target is going to move | away from zero, requiring more control input, which might | _increase_ dx or dy, causing you to need even stronger | control input... | | So the upshot is: you don't have to back out the target's | absolute trajectory, figure out its true velocity and | your own relative velocity, determine range to target and | offset where you're pointing to compensate for time of | flight - just get it to stay on the same bearing from | your perspective, and you're done. | sandworm101 wrote: | It can be easier in terms of getting to a far away | target, of maximizing range, but pointing strait has an | advantage. As the target moves forwards the missile will | be dragged behind, which reduces the relative angle at | intercept, reducing the targets ability to make a last | second maneuver. An direct approach IR missile can | literally fly up the tailpipe of a fast target. | klodolph wrote: | Yes, even old ordnance like the Sidewinder, which entered | service in the mid-1950s, would aim ahead of the target. | sandworm101 wrote: | But which radar to you beam against? The radar in the missile | or the radar in the launching aircraft? Beam against one and | you are not beaming against the other. You are probably dead so | long as one of the two has you. | nradov wrote: | During the initial fly out the missile will usually either be | flying toward a set navigation point, or receiving data link | guidance from the launching aircraft, or cueing off radar | signals reflected by the target from the launching aircraft's | radar (passive homing). You want to keep the missile's own | radar switched off until fairly late in the engagement | because it has limited battery power, narrow field of view, | and will alert the target's radar warning receiver. | | With modern data links it's now possible in principle to | provide target tracking updates from a different sensor (like | IRST) or even a completely different aircraft. If done | correctly the target won't even realize a missile is on the | way until it's too late to evade. | angry_octet wrote: | It's sadly different to Top Gun, when lock on would involve | switching to a different PRF and/or revisit rate. Now, if | they don't turn away after you've launched it could be | because their missile is already on the way... | | At closer range there is still the UV flare of the missile | solid rocket burn, but detecting it depends on weather and | aspect. | sandworm101 wrote: | Or they could be cranking and that turn away is evidence | that they have already launched against you. | Kim_Bruning wrote: | Since the missile is coming from the launching aircraft, both | of them will be on roughly the same bearing; certainly early | on. | | Flying perpendicular to that bearing will thus (hopefully) | result in _both_ sets of radar electronics filtering you out. | | Should the two bearings diverge at some point, I'd recommend | notching against the one armed with the explosive warhead | with your name on it. | [deleted] | [deleted] | sloshnmosh wrote: | My father was a navigator and EWO officer in the C130 Hercules | during the Vietnam war. | | He didn't talk much about the war but one of things he told me | was that while he was that their aircraft had several stubby | antennae around the aircraft that monitored the radar from ground | to air weapons. | | He said they had various jamming equipment and would send back | radar signals out-of-phase so that ground radar would receive | strong signals where they should be weak to throw off the | targeting. | | He said at one point over Cambodia his equipment was overloaded | by being locked on by multiple Chinese made weapons. | | Later analysis showed at least 3 different "Firecan" radar locked | on. | | Luckily they were not fired upon. | | Edited to add that Wikipedia shows that Fire Can as Russian made. | But my father did state he thought they were Chinese made | everyone wrote: | I have ABP yet I saw ads on this page? Are they doing something | dodgy? | cs2733 wrote: | Adblock PLus will let in some ads. Check | https://adblockplus.org/acceptable-ads | opportune wrote: | Most adblockers rely on crowdsourced detection, there are ways | you can report ads so the rest of the community can all block | it. It's possible you ran into a new ad. | | Also ABP allows some ads it deems not intrusive. Ublock origin | is stricter and better in my experience. | everyone wrote: | Tx for explaining! I switched. | frkloovb wrote: | What does "closure rate" mean? | j4yav wrote: | How fast they are approaching each other | sokoloff wrote: | Indeed. The rate at which the gap between them is closing => | closure rate. | thrill wrote: | Even more fun, since closure rate was often written as Vc (Vee | sub See), pilots often spoke in terms of "opening" Vc (getting | further away) and "closing" Vc. | Saint_Genet wrote: | This is largely off topic, but one of the most fascinating things | I've ever learned about fighter jet HUDs is the reason they still | look like early computing interfaces and avoid using color and | graphics to signify important information is that human ability | to detect color goes down when in high stress situations. | esaym wrote: | How radar tracking worked in the good ol' days [0] | | [0]http://www.donhollway.com/foxtwo/crusader.mp4 | dang wrote: | Discussed at the time: | | _How does a fighter jet lock onto and keep track of an enemy | aircraft? (2013)_ - https://news.ycombinator.com/item?id=8439560 | - Oct 2014 (85 comments) | | Also, we changed the url from https://gizmodo.com/how-fighter- | jets-lock-on-and-how-the-tar... to the quora.com page it's copied | from. | dredmorbius wrote: | Given quora is registrationwalled and Gizmodo is not, I'd | support reinstating the submitted URL. | bdefore wrote: | 2014 | avipars wrote: | This is an old article and i'm sure electronic warfare has | improved since then (the IDF invests a lot into this)... | | But it's really cool to read about! | neonate wrote: | https://archive.is/OHCwT | sobriquet9 wrote: | This part looks rather dated: | | > A digital signal processor looks for recognizable radio | "chirps" that correspond to known radars, and displays their | azimuth on the scope. A chirp is a distinctive waveform that a | radio uses. | | These days it should be pretty easy to use pseudorandom | waveforms, unique each time. LPI radars existed for a while. | angry_octet wrote: | Yes it's a tech appreciation from the SLQ-32 era. But at the | same time receiver memory and sensitivity has massively | increased, and many properties can be analysed, including the | response to deception signals (delayed repetition of various | strategies, sidelobe injection). LPI doesn't work for tracking | as well as for searching. In the past it would take months for | new waveforms to be analysed and platform libraries updated, | now it happens in hours. | j4yav wrote: | Really interesting content, but its almost even more amazing how | many ads they were able to squeeze in there at least on mobile. | aleken wrote: | Annoyed me as well. I changed to reading mode (icon on right | side of Firefox mobile address line). Think that got rid of | them. | navbaker wrote: | The thing that most irritates me about those sites is the video | box about halfway down the page that becomes sticky for a bit | after you pass it on mobile. I have to scroll down until it | goes away, then slowly scroll back up until just before it | appears again to continue reading. It's absolutely maddening. | amelius wrote: | Looks like the ads have locked onto you. Perhaps try some | evasive manoeuvres. | gxs wrote: | I came to say the same thing - at one point only 10% of the | screen was article text. | | What a god awful website. | laegooose wrote: | there are adblocker apps for both iOS and Android. Highly | recommended | swebs wrote: | Yeah, I always just go straight to an archive site when I see a | Gizmodo link. | | https://archive.is/MGCOA | fogetti wrote: | On Android you can use a private DNS service, for example | nextdns.io which will block all advertisement on the page for | you. I wouldn't be surprised if iOS would have the same option. | Ueland wrote: | I run PiHole (DNS-based ad-blocker) on my home network, as | the DNS is given out trough DHCP all my devices gets less | ads, including iOS. | FabHK wrote: | And furthermore, the content was from a guy (Tim Morgan) who | answered a question on Quora (linked at the bottom of the | article). So Gizmodo just copies it and puts lots of ads around | it. I don't understand the modern internet. | | https://www.quora.com/How-does-a-fighter-jet-lock-onto-and-k... | azalemeth wrote: | If anything, I think it's worth asking Dang to change the | link on the page to be this one - it's rather bad that this | person's work appears to being just ripped off. | nkurz wrote: | I sent email asking him to change it. | dang wrote: | Ok, we've changed the URL to that from | https://gizmodo.com/how-fighter-jets-lock-on-and-how-the- | tar.... Thanks all! | the_gipsy wrote: | iOS to be specific. On android we have proper adblocking with | uBlock origin. So much about apple and privacy. | marderfarker2 wrote: | I had this concern before I switched to iOS. Turns out you | can install content blockers for Safari. Plus iOS supports | DoH natively so ads are pretty much non existent on my iOS | devices. | Synaesthesia wrote: | It's very helpful. Firefox on Android with ublock origin is | still the best as blocker on mobile but it's nice to have | eg wipr on Safari. | avh02 wrote: | How does DoH help you avoid ads? | the_gipsy wrote: | Did you not get ads on the article? I'm on iOS and every | other paragraph had one. Checked on android with uBlock and | there aren't any. I installed "Firefox focus", supposedly | blocks ads, I guess on the network level. Which iOS | adblocker do you use? | shoto_io wrote: | I run a newsletter. We swore to find the least ad spammed | website when we cover current news and link out. It's getting | more difficult by the day. | StavrosK wrote: | This is a very interesting article, but I was kind of turned off | by the ease with which it described killing people. "To get a | solid kill, just put the plane in the dot and squeeze the | trigger, super simple!" | | I've seen detergent bottles that were more apprehensive about | their process of use. | throwanem wrote: | This is the business that fighter pilots consider themselves to | be in, and that shows through in the way they talk about it - I | had a history teacher in high school who had previously flown | fighters in the Marine Corps, and while he rarely entertained | much discussion on that subject, his approach on those | occasions was similarly matter-of-fact. | | I didn't check to see if the article referenced any sources, | but it wouldn't surprise me to learn that a primary one was a | conversation with an F-16 pilot. | [deleted] | StavrosK wrote: | Yeah, I'd expect pilots to talk like that, it just had an | impression on me because I didn't expect a journalist | explaining something to have the same vernacular. | throwanem wrote: | Fighter pilots are also, by all accounts including my own, | very much among the most confident human beings anyone is | ever likely to meet - that teacher I'm thinking of | certainly was. It can easily make a strong impression; most | of the guys in that class had a huge crush on the idea of | growing up to be like him, while many of the girls (and I!) | just had a huge crush _on_ him. | | There is no reason to assume this sort of thing only occurs | among high schoolers, or in any case that a Gizmodo writer | would be more likely to embark upon a serious consideration | of the moral weight of aerial combat than to focus on its | literal and figurative whiz-bang, wow-cool-robot aspects, | of which there is no shortage. | gostsamo wrote: | The article is a copy of a Quora answer. Not even sure if | there was a journalist involved. | | https://www.quora.com/How-does-a-fighter-jet-lock-onto- | and-k... | | Edit: Quora link. | throwanem wrote: | Ah, written by a pilot and fighter nerd, this also checks | out. | | Fighter pilots are kind of the ultimate cool kids from the | perspective of a milstuff nerd, and there is an unusual | degree of hero worship among that cohort already. | luma wrote: | Anyone flying a fighter jet in aerial combat with other fighter | jets knows what they signed up for and are facing opponents who | signed up for the same thing. | | War is terrible, but this is one of the very few situations in | modern combat where there is a clear line between civilians and | the combatants. Everyone engaged is a willing participant. | | In this situation I'll apply Doug Stanhope's logic: | | > As long as the people who kinda wanna go kill other people | are going to go kill other people who kinda wanna go kill other | people, you're killing all the right people and opening up all | the best parking spaces. | weswpg wrote: | > opening up all the best parking spaces. | | Funny quote, but I don't think front-line infantry have the | best parking spaces. That would be the flag officers. | luma wrote: | Not sure what country you are from but in most air forces, | front-line infantry aren't flying fighter jets. | throwanem wrote: | Close air support blurs the line a little, especially | inasmuch as (in US forces at least) those pilots are both | uniquely beloved among the infantry they support and with | whom they share many hazards, and also much differently | regarded by "real" combat pilots as halfway to being | ground pounders themselves. | StavrosK wrote: | Well, that's sound logic and a great quote, thanks! | rascul wrote: | > Everyone engaged is a willing participant. | | Conscription is a thing in many countries. Not sure how many | conscripts are flying, though. | fb13 wrote: | Well, living in a highly militarized US city that sees vendors | come in for various presentations regularly, not only is | "lethality" a word that businesses use to sell, but also one | everyone gets excited to hear. It's definitely weird at first | as a civilian. But I see how it quickly becomes CAC/LTV. | throw10293847 wrote: | Lock on target: "Snowflake" | scottLobster wrote: | At the end of the day the military is primarily there to | achieve various ends through killing or the threat of killing. | What good would it do to obscure that? Not all killing is bad | tome wrote: | I believe in the vernacular "kill" refers to destruction of the | enemy aircraft not ending the life of the crew (they are | correlated, of course). | StavrosK wrote: | I agree, but still... | usrusr wrote: | Would it be better or worse if they stuck to an euphemistic | verb like "down", as if it was a given that the occupant | walked away? I don't know the answer. | [deleted] | belter wrote: | It is rumored the French OTH-Radar Nostradamus can clearly see | all current stealth airplanes. | | https://ieeexplore.ieee.org/document/1631867 | | https://www.researchgate.net/profile/Jp-Molinie/publication/... | 2OEH8eoCRo0 wrote: | We've had radar that can "detect" stealth since the 40s. | | Radar is a huge field and HN's simplistic view is humorous. | Saint_Genet wrote: | And almost all stealth measures can be defeated by using | multiple sensors. | 2OEH8eoCRo0 wrote: | Stealth is not perfect and not about never being detected, | it's about shooting first. You are going after a military | aircraft that is trying to kill you. By the time you lock a | B2 it has released its bombs. By the time you lock an F35 | you're dead. | | These aircraft don't just fly around and let you take your | sweet time killing them. | | If you manage to lock one you have to deal with this as | well: | | https://en.wikipedia.org/wiki/Radar_jamming_and_deception | | Some of these are quite sophisticated, example: | | >Digital radio frequency memory, or DRFM jamming, or | Repeater jamming is a repeater technique that manipulates | received radar energy and retransmits it to change the | return the radar sees. This technique can change the range | the radar detects by changing the delay in transmission of | pulses, the velocity the radar detects by changing the | Doppler shift of the transmitted signal, or the angle to | the plane by using AM techniques to transmit into the | sidelobes of the radar. Electronics, radio equipment, and | antenna can cause DRFM jamming causing false targets, the | signal must be timed after the received radar signal. By | analysing received signal strength from side and backlobes | and thus getting radar antennae radiation pattern, false | targets can be created to directions other than one where | the jammer is coming from. If each radar pulse is uniquely | coded it is not possible to create targets in directions | other than the direction of the jammer | sudosysgen wrote: | Jamming AESA radars is basically impossible. | | "Find the F35 and you're dead" is just wrong and | simplistic. Head to head anti-air fights aren't what's | gonna happen. The F-35 in every mission it's supposed to | do is going to go heads up against multiple different | detection platforms. | angry_octet wrote: | "Jamming AESA radars is basically impossible." | | This is so incredibly wrong. | 2OEH8eoCRo0 wrote: | Ok | bitL wrote: | Yeah, but how precise it is? Even the old WW2-style radars can | see all stealth planes, but can't really guide a missile | towards them. There was also Czechoslovak Tamara radar in the | '80s that was supposed to detect them as well. And Russians are | supposed to have a mesh of mobile radars that can detect small | anomalies in their plane and combining them together should | show some imprecise location of a target. The question is how | useful any of these are? | topicseed wrote: | Wouldn't air friction on a flying stealth airplane cause it to | be detected due to the heat generated? | | It must obviously be more complicated than that but that should | be doable nowadays? | graderjs wrote: | They ionize the hull in some way to reduce friction I guess | that reduces the thermal signature. | dotancohen wrote: | What do you think "ionize" means in this context? | | Or, for that matter, hull? These aircraft have many layers | of material between the traditional tensioned skin of the | aircraft and the outside air. | baybal2 wrote: | > Wouldn't air friction on a flying stealth airplane cause it | to be detected due to the heat generated? | | Stealth coated airplanes are supposedly flying very slow on | missions to avoid infrared detection. | | It will probably still not do anything against astronomy | grade infrared sensors. | ranger207 wrote: | Yes, there's a lot of work in infrared search-and-track | (IRST) for detecting stealth aircraft. But the atmosphere is | a great absorber of IR so it's not a panacea. | the__alchemist wrote: | The frequency of emitted IR isn't what radars use. | anfractuosity wrote: | Would it be possible to pick up modern OTH radar signals out of | curiosity using amateur radio equipment, such from the | Nostradamus one you mention? | | I believe it was possible to pickup the Russian Duga system. | Nokinside wrote: | Almost certainly. But they can't keep track accurately and the | location of the aircraft is not accurate. The inaccuracy can be | several km. | | Stealth is still 80% of shaping. Specular reflection can be | reflected away from the radar receiver. In the resonant | scattering region, where the signal amplitude matches the | object sizes, you remove radar return by removing all parts | that are a similar size to the wavelength, like the tail. | Coatings and Absorbers reduce radar even return more but only | after the shaping works. | | If you can get radar into an angle that the shape was designed | for, or transceiver and receiver are in separate locations | stealth advantage decreases dramatically. | | Chinese are probably the first to deploy long-range air-to-air | missiles that have dual sensors. Both radar and IR. (Stunner | missile has that already, but it's ground-to-air missile). | Traditionally IR is used only in short-range missiles. You | direct the missile to approximate position and then it uses IR | and radar together to remove stealth. | jandrewrogers wrote: | The launch platforms can feed the necessary positional data | to the missile, which can switch to IR search mode as it | approaches the area of the target. Most newer US platforms | use a mix of inertial and IR imaging guidance. Even the | longer range radar-guided missiles typically don't turn on | their radar until they are relatively close to the target; | effective long-range radar has power requirements that don't | fit in a missile very well. | | The dual-mode terminal guidance on the Chinese missile may be | a response to the fact that the US has very good | countermeasures for IR terminal guidance. IR guidance is | cheap but it may not be reliable against some advanced | targets. | angry_octet wrote: | The diameter of the missile also imposes significant | limitations on the RADAR. IR sensors couldn't be in the | nose cone, it's hard to see them being very sensitive or | capable against active decoys. | | In contrast, the AIM-120D has bidirectional data link, so | it can feed it's RADAR picture back to the launch platform. | p_l wrote: | Or it could be something they picked up from Soviet defense | forces, where the doctrine was to fire long range missiles | in pairs - first an IR seeker then radar one p | sandworm101 wrote: | >> and then it uses IR and radar together to remove stealth. | | So what happens when the dual seekers give different results? | If there were three seekers then you could ignore one, but | with only two you cannot check one against another. What if | the radar says turn left but the IR says turn right? Having | two seekers may make the target's life easier: defeat either | seeker and you defeat both. | nradov wrote: | It's like any other sensor fusion problem. You take a | weighted average of the detected target bearing based on | whatever data you have. Even if the target manages to | completely "defeat" one sensor by somehow becoming | invisible it doesn't mean that sensor will report a totally | spurious bearing; you just won't get any meaningful data at | all from it and thus ignore it. | sandworm101 wrote: | Left + Right /2 = Strait = Miss. | | Small errors count. A few degrees off and your missile | doesn't get to the target. Any averaging will probably | result in a miss. In such cases a single sensor would be | better, or two different sensors on two different | missiles. | | This comes up in all manner of flight systems. Take | altitude. If one sensor says you are at 1000feet and | another says 10,000, the one thing everyone should agree | is that you aren't at 5500. One of the sensors is wrong | and needs to be ignored, but how do you pick between the | two? | nradov wrote: | That's not how modern sensor fusion algorithms work. It's | never a simple average calculation. The inputs from | various sensors are weighted based on confidence levels. | In extreme cases sensors reporting bad or inconsistent | data are ignored. | travisjungroth wrote: | > One of the sensors is wrong and needs to be ignored, | but how do you pick between the two? | | What did the sensors say one minute ago? There's no | reason this has to be Markovian. | sandworm101 wrote: | Because, in a jamming/deception scenario, the jammer | acting on a sensor won't just introduce a false reading. | It will gradually transition from a true to false state | in a manner that looks natural. The jammer will attempt | to capture the sensor's attention and then shift its | attention away from its target ("seduction"). In such | cases it is very difficult/impossible to tell which is | true based on past readings from the sensor. Google | jamming and "capturing the gate" or "doppler pull", | techniques specifically to defeat countermeasures | dependent on past readings. With two sensors against a | jamming target, the sensor with the clearest signal/most | confidence is probably the one being most jammed. (IR | flares do similar things too.) | rocqua wrote: | For others, OTH is Over The Horizon. It uses stratospheric | scattering, much like extra long range radio. | sobriquet9 wrote: | You don't need to go to HF to detect stealth aircraft. Even VHF | will work. But it's not going to be accurate enough for | targeting. | | Another approach is to passively listen for reflections of cell | tower or FM radio signals. Stealth aircraft do not reflect much | radio energy straight back at the source, but they do reflect | it in other directions. | sudosysgen wrote: | VHF is now accurate enough for two-stage targeting. Basically | you guide the missile close enough for its own | radar/camera/ir sensor to lock on. | | VHF is inherently too inaccurate for a lock either. It just | scales with how big the radar is. | touisteur wrote: | So called 'passive' radars. FM radio, cell towers, and also | dvb-t. Wonderful tech. Is there an actual (not toy or PoC) | operational system deployed anywhere? | sobriquet9 wrote: | There is no way to know. An actual operational system | deployed anywhere would be impossible to detect. It does | not transmit anything, and can use existing antennas for | receiving the signals. Can be as simple as software update. | milanmio2 wrote: | anecdotal: friend serving "mandatory" (last) year in Slovak | army during NATO "humanitarian" bombing of Serbia operating | Czech passive radar Vera in east Slovakia could locate B-2's no | problem.It was banned by US to export to China. | 2OEH8eoCRo0 wrote: | Define locate. | belter wrote: | Interesting. It seems the US "took over" the radar. | | https://www.army.cz/scripts/detail.php?id=6159 | hawski wrote: | Interesting, but what does "took over" mean? | totoglazer wrote: | I think it means they bought a set. | _kbh_ wrote: | I thought most OTH can see stealth planes because they usually | aren't optimised for being scanned from the top, but rather | more front, back and bottom face scanning. | | I don't know much about stealth though so I could be completely | wrong. | WJW wrote: | There are many variables involved in radar target detection | and usually "stealth" planes only have the possibility to | optimize for a few of them. As a simple example, radar | absorbing paints usually only work well in a few frequency | bands so using a radar outside that band gives a much higher | chance of detection. Using "blocky" designs reduces the | chance of detection from one angle (typically the front, | since that is where the target is) but at the cost of higher | detectability from another angle. And finally you will almost | always have problems with infrared visibility from some | angles, for a jet airplane it is almost impossible to hide | the exhaust plume when looking from the rear of the aircraft. | | In any case, you are right that OTH skywave radars like the | Nostradamus usually have a pretty good chance to detect | stealthy planes. However due to the frequency bands involved | such detections are typically more of the "there is something | in this cubic kilometre" type and not of fire-control | quality. You need much more accurate systems to actually | guide a missile. Still, it is pretty cool. There are also | "passive" systems which use the reflections of waves from | normal civilian radio stations and a phenomenal amount of | signal processing to determine the position of thousands of | targets simultaneously, although I'm not aware of any in | active service yet. Like fusion power, this type of | "multistatic" radar seems to be perpetually 30 years away | from practical use. | | Source: Used to be a weapons engineer for the Dutch Navy, at | one point specializing in advanced radar systems. | [deleted] | noir_lord wrote: | Wouldn't surprise me - it's the eternal cat and mouse game | between defense and offence and stealth as a concept isn't | _new_ anymore. | | It's not about been totally hidden (sans a cloaking device that | is never going to happen) it's about been _less_ detectable | after all. | | If the distance the stealth platform can see you from is | greater than the distance you can reliably detect them from you | are already dead - the missile simply hasn't arrived yet. | deathhand wrote: | So then this logic brings us to space platforms, anti-space | platforms, and observservations of space platforms. | | Everyone is probably already arming space to the teeth. I | guess it's better than mutually assured destruction? | the_duke wrote: | And stealth space platforms. | | There might already be stealth sats in orbit. | | A curious case was the Zuma satelite [1]. | | Classified payload. Ostensibly failed to detach from the | payload adapter, as claimed by anonymous sources... Lot's | of speculation that this was a media charade to sow | confusion about a stealth sat. | | [1] https://en.wikipedia.org/wiki/Zuma_(satellite) | nradov wrote: | There are no stealth satellites. It's impossible to hide | in orbit due to power and cooling requirements. | | http://www.projectrho.com/public_html/rocket/spacewardete | ct.... | wyager wrote: | This is a funny claim to make given that the US literally | has stealth satellites. | https://en.wikipedia.org/wiki/Misty_(satellite) | | Just because it's physically challenging to avoid having | some blackbody emissions or whatever doesn't mean you | can't evade modern sensors in practice. | nradov wrote: | What's your point? Those satellites were detected. They | weren't actually stealthy in any meaningful way. Very | minor signature reductions at best. | angry_octet wrote: | While amateurs can do an amazing job of detecting | satellites, I think it is pretty likely that there are | smaller satellites which are operating in extreme low | power mode, waiting until a conflict where they are | required. Whether there are enough to replace GPS and | comms lost due to anti-satellite attacks and resulting | debris is a bigger question. | nradov wrote: | It isn't physically possible to get useful GPS service | from a small satellite. This is just basic physics. | Calculate the power required to transmit the necessary | signals. You need some fairly sizable solar panels. No | way to hide those. | mlyle wrote: | I get crummy GPS fixes inside my house with 30dB+ of | attenuation of the signal by structure and parts of the | sky absolutely masked, while using absolutely crummy | antennas. | | To me, this seems to imply you could make a useful system | today with orders of magnitude less transmit power. | orestarod wrote: | Maybe I do not understand something. But you get these | readings, through all these conditions, with the help of | the present, powerful and energy hungry satellites. A | mini, less powerful satellite would not perform the same | under the same conditions. | sciurus wrote: | The military doesn't need GPS to work from inside a | house. | wyager wrote: | "That launch deposited a payload into geosynchronous | orbit but, given the stealth/deception hypothesis, there | remains the possibility of other, undetected payloads" | nradov wrote: | There remains a "possibility" that dinosaurs aren't | extinct and they're hiding somewhere. Just because | civilian astronomers haven't found such payloads doesn't | mean those payloads actually exist. And hypothetically | even if those payloads do exist it doesn't mean other | nations haven't tracked them. | | Wikipedia isn't a reliable source for this stuff. Look at | the basic physics involved. | simonh wrote: | Space based weapons are extremely limited in practice. The | problem is that at any given time 90% or more of your | orbital assets are over the pacific ocean, or the arctic, | or antarctic, or anywhere other than where you want them to | be and you can't change that very easily. | the_duke wrote: | A LEO sat at 300 km altitude does a full orbit every ~90 | minutes. | | Put a few hundred missiles in orbit, give them enough | spare fuel to travel a decent distance on their own, and | you have a pretty substantial worldwide strike | capability. | treeman79 wrote: | Meanwhile opponent straps nuclear hand grenadines to a | few thousand drones and flies them to your bases. At a | fraction of the cost. | hungryforcodes wrote: | And they are not doing that now, because... | catillac wrote: | This handwaves a lot of stuff. The least of which is that | with the way satellites orbit, even though they orbit in | 90, they're not over the same ground track again for like | 12 days. It's not the case that a weapon used satellite | would have a firing solution every 90 minutes. | nradov wrote: | What's the point of that when you can have an even more | substantial worldwide strike capability at far lower cost | with ground-based missiles. | laverya wrote: | Do you know what the difference is between an ICBM and a | warhead predeployed in orbit? | | The ICBM can hit anywhere (instead of just where the | orbit track happens to pass), in less time (or at most | the same time, since deorbiting takes around half an | orbit) with a better mass fraction (since it doesn't have | to reach orbit and then deorbit afterwards) while being | more accurate (you know exactly where the launch platform | is, while satellites are harder to locate) and less | vulnerable (you can harden an ICBM silo far more | effectively than a satellite). | | Really, it's hard to think of something that satellite | anti-ground weaponry does _better_. | rocqua wrote: | Detection? | | There is a lot of icbm detection. Unplanned rocket | launches could lead to global nuclear annihilation. What | happens if something seems to deorbit above the US? How | much early warning and procedure is there? | | Especially if you want to deliver conventional munitions | to a non-nuclear power, a system like this seems better | than an ICBM. | iso1210 wrote: | Tungston rods. Would you even detect the deorbit burn? | dredmorbius wrote: | A/K/A "rods from God" / orbital kinetic kill. | | https://en.wikipedia.org/wiki/Kinetic_bombardment | | Possible, though problematic. | [deleted] | hawski wrote: | I guess it is a question of what type of warhead is there | and how many of them are there. | imtringued wrote: | It's actually about capability inflation. You can counter any | tech but new tech makes old tech obsolete. | | An army consisting exclusively of F-35 vs old generation jets | could decimate all enemy jets without losing a single F-35. | | It's the same with modern tank vs old tanks. Those old tanks | can't penetrate the armor of modern tanks. | sandworm101 wrote: | >> An army consisting exclusively of F-35 vs old generation | jets could decimate all enemy jets without losing a single | F-35. | | Maybe ... in the air ... if the numbers are the same ... if | all of those F-35s are able to fly ... if the other side | doesn't have a significant SAM capability ... if if if. In | a realworld battle between armies the air-to-air capacity | of fighters is a small part of the battle. Most will try to | defeat the other's aircraft using ground assets, | missiles/manpad. Ideally you take out aircraft in their | hangars. A single well-placed artillery shell can take out | a dozen F-35s in a hangar. A single frogfoot can destroy | any F-35 that is low on fuel/ammo/speed after engaging a | couple flankers. Realworld combat is messy. A pack of crows | can take down an eagle. | belter wrote: | You sure about that ? Because at least in dogfights the 40 | year old F16 seems to win.. | https://arstechnica.com/information- | technology/2015/07/disas... | [deleted] | wil421 wrote: | The F22 would probably be the one engaging F16s. | Regardless if you are dogfighting in an F22 or F35 | something else has gone wrong. The stealth planes sneak | in and shoot enemy planes from far away. | belter wrote: | I am afraid they tried that also.The F22 lost against | German pilots on the Eurofighter Typhoon: | | https://abcnews.go.com/blogs/headlines/2012/07/f-22-fight | er-... | wil421 wrote: | The article hits on my point about dogfighting. I don't | think most US modern planes except the F16 were designed | for it. IIRC they weren't even going to include guns on | the F22. | | > while the planes own the skies at modern long-range air | combat | gpderetta wrote: | Any scenario in which American F22s would participate in | combat action against European Eurofighters is far | fetched, dogfighting or not. | | In fact I would say if such an encounter were ever to | happen, due to rule of engagements, a dogfight would be | more likely than a BVR engagement (and likely to end | without a single shot fired). | knowaveragejoe wrote: | "Old school dogfighting" is just that - a thing of the | past. | elygre wrote: | The premise was "consisting exclusively of F-35". you | might have wanted F22s, but they are not available in the | scenario. | stouset wrote: | This is irrelevant. The exercise was dogfighting, a phase | which the F-16 would never be able to reach against an | F-35 in combat without a multitude of things going wrong. | | The F-35 can see and shoot down the F-16 with radar- | guided missiles in BVR well before the latter is even | aware the F-35 is in the area. | | Dogfighting is minimally relevant to modern air combat | for nuclear-armed nations. Things would have to be going | extraordinarily badly in a war for the brass to start | deciding to send their exceedingly expensive fifth-gen | stealth fighters into dogfight coin tosses. | | Hell, even an A-10 is a surprisingly effective dogfighter | against modern fighters. The fighters have speed but the | Warthog has an extremely tight turning radius and far | better low-speed maneuverability, both of which allow it | to stay inside the opponent's "bubble" (the area inside | which a turning jet can't ever manage to point its nose). | If the A-10 can keep it to a one-circle fight it will win | handily. A fighter will often have to rely on a "boom and | zoom" tactic (where it disengages, gains distance, and | turns back around for a guns pass) but that can be quite | low probability of kill and still be relatively risky if | the A-10 has friendlies in the area feeling it location | information. | | But just like the situation already being discussed, this | is for all practical purposes completely irrelevant. A | flight of F-16s would engage and destroy a flight of | A-10s from miles away with AMRAAMs and it would never | have a chance to transition to an up-close dogfight. | valec wrote: | > The F-35 can see and shoot down the F-16 with radar- | guided missiles in BVR well before the latter is even | aware the F-35 is in the area. | | what's stopping the f-16 from turning around and going | cold as soon as it hears a lock or senses enemy radar? | orestarod wrote: | I believe missiles have a certain range at which, when | fired, the kill is ensured. The F35 would not need to | fire the missile at the absolute possible range the | missile can fly to, but at the range the kill is | guaranteed. | the__alchemist wrote: | Sort of. You can get to a range where kinematically | defeating the missile is unlikely / impossible, but it | still might fail due to any number of problems that can | happen during the intercept. | wearywanderer wrote: | The rules of the wargame, which are invariably rigged for | the most expensive toy. | [deleted] | tynpeddler wrote: | The linked article is out of date and cites "War is | Boring" which is notoriously anti f35. Here's something a | bit more recent. The english translation is at the botom: | https://nettsteder.regjeringen.no/kampfly/fagprat/f-35-i- | nae.... | canadianfella wrote: | Been? | aparsons wrote: | Cat and mouse games lead to very surprising innovations. | | During the Sri Lankan civil war about 10 years ago, the Tiger | rebels had acquired Zlin Z 43s, modified them to carry | several bombs [1], and were bombing targets left and right, | including the country's capital. | | The populace was increasingly pondering why the country's | well-trained air force, with modern fighter jets with years | of scrambling experience [2] could never seem to shoot these | slower planes down. In fact, there were no confirmed kills | during the conflict. | | It was later revealed that the rebels knew the capabilities | of the enemy Chengdu J7 and MiG 29 interceptors, and had | modified their own aircraft engines with anti-IR capabilities | [3]. Complex IR jamming equipment was suspected, but the | country's PM later said that the rebels had simply redirected | the exhaust fumes from the back of the aircraft to the front, | throwing "unlockable" heat signatures [4]. | | By the end of the war, the rebels had actually "won" the war | in the skies by destroying over 30 aircraft and losing 2, | despite ultimately losing. | | [1] https://en.m.wikipedia.org/wiki/Zl%C3%ADn_Z_43 | | [2] The government's prized jet fighters were stationed in | the capital, about 400 km from the main conflict zone. In | 2000, the rebels launched a devastating offensive and the | government held on by a thread due to their ability to | scramble ground attack craft to battles in 7 minutes. It's | said that had they lost that battle, all hopes of winning the | war would have been lost. | | [3] http://www.sundaytimes.lk/081102/Columns/sitreport.html | | [4] https://www.dailynews.lk/2020/01/18/local/208783/slaf- | most-e... | jFriedensreich wrote: | would have loved to have audio examples for the article. as it | reads the audio feedback to pilots is not a database of warning | tones but a direct translation of the received radar spectrum to | something audible. if someone has a good link it would be | appreciated. | the__alchemist wrote: | The info in this article mainly applies to mech-scan radars; many | fighters from all over the world now use AESAs[1] (This includes | 5th gen, and upgraded 4th gen). These don't have the distinction | of "track" and "search" modes; the radar maintains high-quality | tracks of multiple targets in the radar coverage, and the crew | can select which ones to target. | | [1] | https://en.wikipedia.org/wiki/Active_electronically_scanned_... | dogma1138 wrote: | AESA radars very much do have track and search mode, it's just | not mechanically controlled so they can track more targets | however once you lock on a target(s) the beams are still | focused on them which is why you still have a limit and that | limit is dependent on the size of the target you track as well | as it's range and not just the radar itself. | | An AESA radar that can track up to 5 targets for example might | still be limited to a single target with a low RCS because more | of the array has to be focused on it. | the__alchemist wrote: | All valid points. In practice for non-stealth fighter-size | targets, (Depending on the software/UI) you can park the | radar in a general-purpose mode, and get decent-quality | tracks for many contacts. Turning them into higher-quality | "weapons-quality" tracks (eg for shooting) taxes the radar | more. The more you ask of the radar (More wpns-quality | tracks, SAR mapping etc), the poorer its performance. | ilovwindows wrote: | I have always wondered, wouldn't it be pretty easy to create a | missile that follows a radar wave to it's source? A fighter plane | could use this very missile to shut down a fighter plane chasing | it or a ground radar scanning it. | kop316 wrote: | Yep! | | https://en.m.wikipedia.org/wiki/AGM-88_HARM | | https://en.m.wikipedia.org/wiki/Wild_Weasel | byteofbits wrote: | This is essentially how HARM (Anti-Radiation) missiles work | [https://en.wikipedia.org/wiki/AGM-88_HARM] | mardifoufs wrote: | It already exists! Also works against ground radar. It's | actually one of the best ways to clean up enemy air defenses | before an invasion | | https://en.m.wikipedia.org/wiki/Anti-radiation_missile | scottLobster wrote: | Yes, term you're looking for is anti-radiarion missiles, | they've been around for a little while | https://en.wikipedia.org/wiki/Anti-radiation_missile?wprov=s... | muro wrote: | Some loitering ammunition also do that. It waits in the area | until SAM battery turns on their radar, then it knows its | position and destroys it. | Buttons840 wrote: | After going down the rabbit hole of combat flight simulators | (Falcon BMS), I learned about Suppression of Enemy Air Defense | missions. Fly to a spot, fire off a few radar seeking missiles | at an area, the missiles are programmed to hit any radar they | detect. The missiles go in a straight line for several minutes | watching for radar, and will quickly fly towards any detected | radar and blow it up. So, to support nearby missions you just | put out a few of these missiles over and area and then nobody | dares turn on their ground radar. | skhr0680 wrote: | I recall Serbia having some success baiting anti-radiation | missiles with tactical microwave ovens | varjag wrote: | It's a successful urban legend. | abandonliberty wrote: | Like carrots being good for your eyes. | des1nderlase wrote: | This statement is quite on spot, as carrots were used to | cover radar tech. | | https://www.livescience.com/38861-carrots-eyesight-myth- | orig... | magicsmoke wrote: | Seems like this could be mitigated by having a network of | radar emitters that periodically turn on and off while | sharing targeting information through the network to non- | emitting missile launchers. Maybe the emitters could also be | mobile and drive away to deter inertial-based targeting. | Seems almost like a shoot-and-scoot artillery system except | with radar instead of rounds. The concept would also work by | networking the radars of a flight of fighters together so | none of them would have to continuously transmit while also | allowing fighters to illuminate targets from multiple angles. | stouset wrote: | This is precisely how modern IADS (Integrated Air Defense | Systems) work. You have long-range search radar deep in | your territory which can alert to contacts entering your | airspace and feed that information to tracking radar | located nearer to the front lines. Tracking radar only | needs to fire for as long as necessary to get a lock, fire | on an aircraft, and allow the radar-guided missile to | establish its own lock. | | Missile launch sites are located separately from radar | sites so they can't be targeted (since they have no radar | emissions themselves) and so that pilots don't know ahead | of time where to look for missile plumes for visual | indicators of a launch. | | All of these sites are networked so can feed information | across a large region and back to a hardened command center | far away. Sharing information this way allows minimizing | the amount of time between a vulnerable front-line system | revealing its location and launching a missile at its | target. Tracking radar and missile sites can even wait to | become active until a hostile aircraft is over or even past | them to defeat wild-weasel style tactics. | | Both tracking radar and missile sites are also often mobile | so once they've disclosed their location by using radar | and/or firing a missile, they can quickly move to a new | location to avoid retaliatory strikes from anti-radiation | missiles and regain the element of surprise. | parsecs wrote: | This is pretty much what they do nowadays. Look at patriot | or S-400: the launcher, fire control radar, acquisition | radar, are all mounted on trucks that can drive around. The | radars do indeed share information with other assets like | that. However anti radiation missiles ("ARM") are still a | threat as the system won't function if all the radars are | out | stouset wrote: | This is the principle behind anti-radiation missiles like the | AGM-88 HARM. It's impractical for A2A combat because in this | situation, the enemy missile is _already_ fired at you and all | else being equal will hit before yours does. | | https://en.m.wikipedia.org/wiki/AGM-88_HARM | belter wrote: | Already exists. Meet the AGM-88: | | https://fas.org/man/dod-101/sys/smart/agm-88.htm | kevin_thibedeau wrote: | The British ALARM is more interesting as it has a loiter mode | where it can fly up, deploy a parachute, and wait for a radar | site to turn on. | | https://en.m.wikipedia.org/wiki/ALARM | imtringued wrote: | It's basically a flying naval mine with an active tracking | mode. | Tycho wrote: | The way the target can "hear" the radar lock seems very | equitable. As if the nature of arial combat is the product of | balanced gameplay mechanics. | nazka wrote: | Or you can use the thermal mid range missile for Sukhoi that | the Russians love and you never have any detection warning | ever. From lock to impact :) | | I love those in DCS. | | https://youtu.be/YCrrmL8GlSY | vmception wrote: | Would be interesting if computer games accurately did lock on | and detection | | Right now it just seems like aiming reticule edge detection | sitzkrieg wrote: | falcon 4.0 is unmatched. they actually had too much and were | forced to redact and simplify some mechanics before release | nazka wrote: | Was about to say it. Get Falcon 4.0 then do the Massive! | Free! update named Falcon BMS. They really coded the radar, | emissions, warming detectors, etc.. Not just a if locked | then give a pin/warning lock to the target type of logic. | Super impressive stuff and we are not even talking about | the dynamic campaign and how all ground radar and ground to | air missile platforms work together for instance. There are | so many things. And I play DCS a lot. But Falcon BMS is | unbeaten for that. | kortex wrote: | I played Descent in the 90's and there was missile lock. It | would trigger when a homing missile had a line of sight to | your ship, and the frequency of the beeps indicated | proximity. It's not the aiming reticle, cause bots could get | you around corners with homing missiles. | | The homing is probably done exactly like graphics, with ray | tracing. | zokier wrote: | Simulators, DCS in the forefront, have somewhat reasonable | radar modeling, both in terms of radar warning systems and | target acquisition. | LightG wrote: | Microprose F-15 Strike Eagle in the early 80's did a decent | lock on and detection! | scottLobster wrote: | There are simulators that do that, but it does take away from | the "Maverick/Top Gun" escapist fantasy most games with | fighter jets strive for when you can't even see your target, | so it's a much smaller market | m12k wrote: | I guess the "gameplay" is somewhat self-balancing in the sense | that as soon as one strategy becomes dominant, there's that | much more incentive to come up with a strategy that counters | it. For that reason alone, in nature, and our mimicry of it, | "it's a tradeoff" or rock-scissors-paper-like scenarios are | much more likely than "one strategy to beat them all". | wyager wrote: | That's why it's so interesting that only humans came up with | the absolutely game-breaking OP strategy of being smarter | than everything else. | des1nderlase wrote: | Not sure that it's game-breaking, depends on how you define | the game. For example, I think that humans can't | exterminate all insects [1], or bacteria[2] alive. However | the other way around I'm not so sure. | | 1. https://www.si.edu/spotlight/buginfo/bugnos | | 2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991899/ ___________________________________________________________________ (page generated 2021-06-12 23:00 UTC)