back to article China claims Starlink signals can reveal stealth aircraft – and what that really means

According to a Chinese state-sanctioned study, signals from SpaceX Starlink broadband internet satellites could be used to track US stealth fighters, such as the F-22. They can claim that all they want but the reality is: It's not that useful militarily, and if it were, Beijing almost certainly wouldn't let anyone blab about …

  1. DS999 Silver badge

    I'm skeptical

    The design of stealth planes like the F22 is intended to create as small a radar cross section as possible, by avoiding large areas of signal reflection. If whatever is not absorbed is scattered widely, the amount reflecting to any one place is small and that's why stealth works. Using passive signals to track a drone, which is not designed to be stealthy in any way, and track a stealth fighter, which is, is a far easier problem. Not saying its impossible to track stealth airplanes that way, but saying "hey we did it with off the shelf drones so we bet it works for F22s also!" is a wild extrapolation.

    Seems like the sort of thing they'd release hoping to worry the US. If they really wanted to know if it worked on F22s they'd test it on their best stealth aircraft and see how much more difficult those are to track than commercial drones. Which they probably did or will do, but they'll never release the results of THAT study!

    1. Wellyboot Silver badge

      Re: I'm skeptical

      Stealth aircraft are designed to prevent returning a radar signal in the direction it arrived from, all aircraft have a large radar cross section when viewed form above*, the problem is that when flying at low level below them is an entire planet also bouncing the signal back (Doppler shift radar fixes this).

      * the only shape that will get the same radar return from any angle is a sphere.

      1. KittenHuffer Silver badge

        Re: I'm skeptical

        In a vacuum?

        1. Martin-73 Silver badge

          Re: I'm skeptical

          Moo

          1. lglethal Silver badge

            Re: I'm skeptical

            No no no, it's a sheep in a vaccum. The correct approved El Reg Soviet sound would be "Baaaa...."

            1. John Brown (no body) Silver badge
              Boffin

              Re: I'm skeptical

              In a vacuum, no one can hear you Baaaaa! So the correct "sound" is the sound of silence :-)

              1. Anonymous Coward
                Anonymous Coward

                Re: I'm skeptical

                aha hello darkness my old friend.

      2. Clausewitz4.0 Bronze badge
        Devil

        Re: I'm skeptical

        "the only shape that will get the same radar return from any angle is a sphere."

        Thank you for the physics explanation. Will work a bit on that in the future.

        * By the way, we all know F-35s are NOT STEALTH AT ALL. Amateur radio operators, it was heard in some circles, can spot F-35s easily.

        1. imanidiot Silver badge

          Re: I'm skeptical

          Compared to other fighters of comparable size, F-35s are very stealthy. They're not stealthy at all compared to an F22 or an F117, sure, but they don't need to be. Also, the vast majority of encounters the HAMs will have had with an F-35, it will have been carrying radar fences to make it less stealthy (on purpose. In peace time it's handy to be able to track your fighters on your radar screens. They were likely also just carrying a standard ADS-B transponder and sending their exact GPS location every second.)

      3. Anonymous Coward
        Anonymous Coward

        Re: I'm skeptical

        Sounds like a classic physics assumption: "Consider a spherical F22...."

    2. disillusioned fanboi

      Re: I'm skeptical

      Stealth works hard to remove direct reflection. Random scattering still works. An F22 is huge, they're saying that the drone they chose has an equivalent behaviour - who knows, but sufficiently true to look for a grant for further research.

      Distributed radar can easily locate a stealth airplane, as can a UHF radar.

      As the author suggested, you need each link of a kill chain to work to actually get a military benefit.

      So you could scramble a fighter to intercept the UFO you detected with your starlink scattering radar, and then launch heat seeking missiles at it.

      Or you could discover that someone spoofed your starlink radar and you'd scrambled planes for nothing,

      1. Roland6 Silver badge

        Re: I'm skeptical

        > As the author suggested, you need each link of a kill chain to work to actually get a military benefit.

        A military benefit can be just knowing something is there. A build up of data on routes etc. starts to give intelligence…

        With respect to the current situation, with China flying “weather balloons” over the USA, this can simply be China saying to the US we can see the paths your stealth aircraft are taking.

        1. Alan Brown Silver badge

          Re: I'm skeptical

          The US military was reportedly furious about the "discovery" of those balloons, as they'd been tracking them for years and they could no longer rely on letting the chinese see what they wanted them to see

          Balloon spying isn't exactly new. The USA and USSR were both doing it in the 1950s-80s (presuably ongoing)

      2. Richard 12 Silver badge
        Alien

        Re: I'm skeptical

        "There may be a UFO"

        It's not much miltitary use unless you can find both position and velocity to a relatively high precision.

        Needs to be enough to identify it as unnatural (eg going too fast) in a place where there shouldn't be anything according to air traffic control and your own military, quickly enough to be able to scramble your own assets to do "something" about it.

        Given that they published, this is unlikely to be able to distinguish birds from planes from toy quadcopters - could just be information warfare, perhaps trying to get the US to waste resources on a dead end.

        Or perhaps trying to convince DARPA that it is a dead end...

    3. simonlb Silver badge
      Stop

      Re: I'm skeptical

      I'm not going to trust anything released by a Chinese state sponsored agency as it's almost certainly disinformation or of marginal use at best. Also, this work was done in Wuhan, where Covid originated, but the Chinese swore blind for years it never came from there. They have no credibility whatsoever.

      1. Alan Brown Silver badge

        Re: I'm skeptical

        If you think the Chinese have a monopoly on releasing misinformation, I have a bridge with nice bascules I'd like to sell you in London.

      2. imanidiot Silver badge

        Re: I'm skeptical

        The Chinese are still swearing blind that COVID didn't originate in China. That's nothing new.

        1. StudeJeff

          Re: I'm skeptical

          Yes... and the Chicoms are liars.

    4. thames

      Re: I'm skeptical

      As mentioned by others, stealth mainly works by minimizing reflections back to the source, not by absorbing the signals. The angles are calculated to reflect the radar "pings" off in another direction.

      Newer submarines such as the German 212 CD are starting to do the same thing for sonar. They have long used acoustic tiles to try to absorb signals, but this is much less effective than reflecting the sonar pings away in another direction (the new submarines of course will use both methods). These newer submarines use a diamond shaped outer hull instead of a cylindrical one conforming to the shape of the pressure hull.

      The idea of using separate transmitters and receivers for radar in order to detect stealth planes is not new. This is called bistatic radar (an old idea which has become new again) and has been known about for years and has been tested with things like television and cell phone tower signals. They look for the "holes" in radio signals rather than looking for reflections.

      What these Chinese scientists have done is shown a proof of concept that it can be done using Starlink signals. Other satellite constellations of course could be used as well.

      I have to disagree with the author of the Reg story however with regards to whether this is useful. If you know that something is there and have a rough location and direction of a target, you can start to bring assets in such as fighters or drones to pin point the location and use other shorter ranged detection means for terminal homing. The big problem has been knowing whether there is anything there to find, and this area of research (and other people are working on the problem as well) tries to address that.

      It's like the situation with over the horizon radar. It can't be used for targeting either, but that doesn't mean that it's not extremely useful. This is why many billions of dollars are still being spent on it today.

      One other advantage of using satellite signals (or other bistatic radar systems using ambient signals) is that they are much harder to knock out because they don't transmit, they just receive. American air warfare doctrine for example places heavy emphasis on suppressing enemy air defences as the first step in any war, and a big part of this is finding and destroying all radar transmitters when they turn on. Using ambient radio transmissions for air warning throws a wrench into the works in this regards. This is the aspect of bistatic ambient radar that really has people interested.

      1. Mishak Silver badge

        Cell phone tower signals

        I was told by someone who was there this was used at the Farnborough Air Show many years ago to allow a ground-to-air missile system to track an F-117.

        I do not know if that was just a story and I can find no evidence to support the claim, but it is plausible.

        1. thames

          Re: Cell phone tower signals

          This was a US B2 bomber which was tracked by a British Rapier surface to air missile system as it flew over Farnborough Air Show. They detected and tracked it using their infra-red sensors built into the launch system. Because the missile was command guided it didn't need a radar return signal to home in if it had been launched.

          In the version of the story that I read about the Rapier vendor (BAe originally, now MBDA) recorded the tracking incident and were playing it on continuous loop at their sales booth until the US made a big fuss with the air show hosts and had the latter make them stop.

          Again, what I heard was that they "cheated" a bit because they knew where to look in the first place and so could point the missile launcher (which had the sensor system built in) in the right direction to pick it up.

          And this is why a radar system that can't be used to provide terminal homing signals is still useful. If you can tell that something is there and give a rough location, you can then start working on the problem of find tuning the location using other sensors that have a much narrower field of view.

          1. Anonymous Coward
            Anonymous Coward

            Re: Cell phone tower signals

            > they "cheated" a bit

            This reminds me of one of my favorite stories. The USAF did SR-71 interception exercises with F-15s. The F-15 squadron was all "we're sooper leet SR-71 killers!" until one exercise where the SR-71 blokes DIDN'T say exactly when they were coming. Result: no more interceptions and the F-15 guys were all crying about how mean and unfair that was.

        2. Dr Dan Holdsworth
          Boffin

          Re: Cell phone tower signals

          Many, many years ago during the first Gulf War the phenomenon of radar reflections from cell phone towers was reported, presumably with the adjunct that Iraqi gunners were insufficiently advanced to be able to do much with the occasional flashes of radar reflected from Allied planes.

          Researching the phenomenon for something entirely different, I have found that this phenomenon has been known for almost as long as there have been "stealth" aircraft. Researchers at the secretive Roke Manor site have been using this sort of thing for ages; a modern society creates so much noise in the microwave spectrum that almost anything flying over a modern city will be visible from backscatter. All the Chinese are doing is blowing smoke and reporting a well-known phenomenon from a different source.

          1. John Brown (no body) Silver badge

            Re: Cell phone tower signals

            From the article, it's doesn't seem to be anything to do with (back) scatter. They are monitoring the Starlink transmission beams and looking at variations when "something" passes through it and causes a disturbance in the "force". With enough sats, and there a lot and numbers rising, triangulation should be possible with some fairly wide error margins. And even it was using that same phenomenon you describe over cities, it's using an in orbit source that could work everywhere, not just over relatively few and far between ground sources, ie cities.

            I fully agree with the article that if this was genuinely useful, they'd not be publishing, but it does seem to be something different and "unique". Is USPO terms, it's easily unique enough for a patent or three :-)

            1. Alan Brown Silver badge

              Re: Cell phone tower signals

              And by publishing, they've just prevented any USPTO attempts...

              ...supposedly

          2. John Smith 19 Gold badge
            Unhappy

            "a modern society creates so much noise in the microwave spectrum that..

            ..almost anything flying over a modern city will be visible from backscatter."

            Not just cities.

            Several groups have used GPS signals to get data on sea state (far out to sea) using special receivers (and lots of post processing).

            I always through this especially impressive as the GPS signals spread their power over a very wide bandwidth in order to be very difficult to jam.

            IIRC several of them have flown on satellites, including cube sats.

            The alternative is an active sensor which is going to be much more expensive and need a frequency allocation valid across the whole planet. Making sense of GPS signals seems quite simple by comparison.

            1. I could be a dog really Bronze badge

              Re: "a modern society creates so much noise in the microwave spectrum that..

              I always through this especially impressive as the GPS signals spread their power over a very wide bandwidth in order to be very difficult to jam

              You need to lookup a bit more about how they work. Yes, they use spread spectrum, which if done carefully can mean your signal is actually below the noise floor. But once your correlator is locked to the spreading signal of the transmitter, it suddenly becomes a high power, narrowband signal.

              And in one of those "who'd have thought it" things, it's something Hedi Lamar (yes, the actress) tried to interest the US military in - but they didn't see any value ! https://www.aps.org/archives/publications/apsnews/201106/physicshistory.cfm

              1. John Smith 19 Gold badge
                Thumb Up

                "it suddenly becomes a high power, narrowband signal."

                I am aware, but when you're looking for sea state conditions you're looking to use it like radar, very much not what it's designed for. Hence the remark about "lots of post-processing".*

                And yes I was aware of Hedi Lamar's work in spread spectrum. AIUI what she came up with was "Frequency hopping" SS as opposed to the code diversity form that GPS uses.

                What impressed me was the lateral thinking involved. Lamar turning music into a form of covert communication and the weather people repurposing the GPS signals for far-out-to-sea wave monitoring.

                Years ago I came across possibly one of the first "software radios" in some back issues of Electronics and Wireless World that used a Transputer for decoding. I thought the idea of generating a single "average" GPS code and using that to flush out which satellites were in view was pretty smart.

                *Of course with Amazon and Microsoft offering virtual cores the cost of that processing has dropped substantially. Not to mention that 1 hours processing in 1970 is about 1 second in 2024.

        3. Dave@Home

          Re: Cell phone tower signals

          Pretty sure it was a variant of that approach used by the Serbs to drop a F-117 back in the late 90s

          1. Alan Brown Silver badge

            Re: Cell phone tower signals

            The Serbs knew what path the F117s were repeatedly flying and pointed their missiles in the right direction to pickup a strong reflection when the bomb bay doors were opened and then home in on weaker reflections thanks to the stealth coating being partially compromised by rain

            They knew when to expect the aircraft thanks to civilian observers phoning in the takeoffs from Italy

            In other words, the USA failed badly in several aspects of security and intelligence, leaving themselves wide open to being nerfed. Hubris leads to Nemesis, etc

            1. TheMeerkat Silver badge

              Re: Cell phone tower signals

              Actually no.

              They tracked the aircraft visually and switch on the radar just before they launch the missiles thus avoiding the radar to be destroyed if it constantly emitted before that. The Soviet-made missiles were designed to be guided by a radar so they would not otherwise hit the target.

        4. Alan Brown Silver badge

          Re: Cell phone tower signals

          Stories of such things should be taken with a grain of salt

          When flying in "friendly" skies, "stealth" aircraft usually deploy surface mounted radar reflectors (Lunberg lenses) both in order to prevent the other side characterising their real radar profiles and to enable tracking by civilian radar systems

          1. Jellied Eel Silver badge

            Re: Cell phone tower signals

            When flying in "friendly" skies, "stealth" aircraft usually deploy surface mounted radar reflectors (Lunberg lenses) both in order to prevent the other side characterising their real radar profiles and to enable tracking by civilian radar systems

            That sounds like something air forces could have some fun with. Vary the profile of the Lunberg lenses regularly, and randomly and really confuse the opponents. Shape-shifting F-35s FTW!

      2. Ken Hagan Gold badge

        Re: I'm skeptical

        " If you know that something is there and have a rough location and direction of a target, you can start to bring assets in such as fighters or drones to pin point the location and use other shorter ranged detection means for terminal homing. "

        On the other hand, if you can impersonate an F22 with a toy drone then the technique is fairly easily and cheaply rendered militarily useless. Just put several thousand "F22"s into the air and let the other guy try to figure out which one has the pointy sticks attached.

    5. I am David Jones Silver badge

      Re: I'm skeptical

      I understood it as sensors on the ground measuring disturbances in the signal coming from Starlink satellites. However stealth an aircraft is, EM signals won’t pass through it (yet!) and apparently this can be detected.

      Maybe it is a bit like detecting planets passing across their stars? That’s always seemed a bit black-magicky to me, measuring such small differences.

      1. Alan Brown Silver badge

        Re: I'm skeptical

        If you've ever watched VHF analog TV in a fringe zone using rabbit ears, you'll know how moving around causes the picture quality to vary wildly

        It's more or less a more complex version of using that to trangulate the source of the disturbance (or trangulating the source of a ghost image on TV by calculating the time offset of the ghost on a couple of receivers)

    6. Number6

      Re: I'm skeptical

      There might be something in it. In the early days of stealth technology there were moves to create a stealth warship[*], but one of the limitations was that while you couldn't see a positive return from the ship, what you ended up with was a hole in the general noise caused by the returns from the sea. So if you were paying attention, you could deduce the rough location by where there wasn't such a noisy return. It's quite possible that the same trick could be applied to an F22 - if everything around it is providing a good return then it's sitting in the quiet hole in the middle. A lot harder to do, of course, because a warship tends to be a lot bigger than an F22.

      [*] I know they have improved the warships to reduce the returns, if you compare a modern one with a WW2 destroyer and all those random reflecting surfaces, they're a lot harder to spot directly, and looking for the hole is going to be a lot harder.

      1. I am David Jones Silver badge
        Happy

        Re: I'm skeptical

        Are you sure a warship is bigger than an F22 and not just closer?

        1. jake Silver badge

          Re: I'm skeptical

          "Are you sure a warship is bigger than an F22 and not just closer?"

          Yes, I am certain. Putting it in IT terms, it turns out that radar is inherently a very good TDR.

          Yes, I know, some purists still call it RADAR. So shoot me. Written English mutates as technical acronyms pass into common usage. Even kinda-acronyms.

      2. jake Silver badge

        Re: I'm skeptical

        Sea Shadow (see Wiki for more) was very stealthy.

        She had one major flaw ... Like all boats, she left a wake behind when moving. Granted, the wake was quite minimal for a vessel of that size, but it was very visible on radar nonetheless.

    7. Alan Brown Silver badge

      Re: I'm skeptical

      It's widely believed that HF Over-the-horizon systems like Jindalee are more than capable of viewing "stealth" aircraft due to the "top down" angle they provide

      Jindalee had sufficient range and resolution when first commissioned in the 1980s to be able to demonstrate to journalists live views of it observing aircraft landing/taking off at Singapore's Changi airport - a distance of nearly 4000km

      Such claims have subsequently disappeared from the records but are still preserved in print media of the time (Electronics Australia and ETI are 2 examples)

      Stealth is a nice marketing term for "low observable", but the reality is that whilst these aircraft are geared for minimal reflections and IR emission, it's difficult to prevent them causing "distubances in the ether" (changes to the overall electromagnetic spectrum as they pass) or to mask them at HF

      That said, whilst HF radar might tell you a stealth aircraft is in the area, it can only give a very general idea of "where in the area" may actually be. It's not so much about being "invisible" as being difficult to pinpoint (It's also worth noting that most "stealth" aircraft coatings don't work well in the rain and require constant reapplication in order to be effective)

      1. thames

        Re: I'm skeptical

        Over-the-horizon systems like Jindalee are high frequency by OTHR standards, but they're still very low frequency by conventional radar standards. Since low frequency conventional radar can detect stealth aircraft just fine, it's theoretically possible that Jindalee can as well, although I haven't read anything which states that specifically.

        Present day stealth doesn't work when the radar wavelength is a significant fraction of the size of the entire aircraft, as the whole aircraft becomes the reflector rather than individual parts of it. This is why supposedly "obsolete" radar systems which some countries which couldn't afford new ones have can detect stealth aircraft.

        However, antennas get bigger as frequencies get lower, and you can't fit an antenna for such a radar into a missile to use it for conventional semi-active or active homing (where the missile uses the radar reflections directly to home in on the target). This is what is meant when people say they "can't be used for targeting".

        However, military radars are not all used for targeting anyway. There are warning, search, and targeting radar systems, and they tend to operate on different frequencies and have different roles in the overall process.

        The Jindalee system cannot be used for targeting against any aircraft, stealth or non-stealth, but that doesn't mean that it hasn't been something very useful for Australia to have in order to see whether something is coming their way from the northern direction.

        Canada uses OTH radar as well, pointing off the east coast and has been developing one which can work in Arctic conditions. In the latter case interference from the Aurora Borealis has until now prevented OTH radar from working in the Arctic to detect Russian bombers coming over the north pole, so Canada operates a chain of conventional radar stations in the Arctic for that purpose (the North Warning System), and they are coming up as due for replacement. However, Arctic OTH is now apparently solvable with enough computer processing power and so an Arctic OTH radar is close to deployment.

        The issue with using passive radar based on ambient radio signals has face the similar problem of requiring massive amounts of signal processing in order to make it work. This sort of signal processing is however now practical according to various reports. Lots of people are doing research into this area, and what these Chinese scientists have done is to show that Starlink satellite signal may be viable as one such source of ambient radio.

        1. David Hicklin Bronze badge

          Re: I'm skeptical

          > However, antennas get bigger as frequencies get lower,

          So we need to resurrect the British Home Chain RDF from ww2 complete with huge towers then ?

    8. Robert 22

      Re: I'm skeptical

      This is basically a form of bistatic radar. Such a radar is distinguished by the location of the transmitter and receiver at different positions. Here there is the further twist that a signal from a transmitter intended for an unrelated use is being opportunistically exploited. The idea has been around since the earliest days of radar. The Japanese used bistatic radar systems in WW2. They were used in Canada after WW 2 for a period in the north (the McGill Fence/ mid-Canada Line). More recently, it has been realized that they have potential advantages for detecting stealth aircraft since one of the stealth techniques is to scatter the reflected energy in many different directions.

  2. bartsmit

    Starlink? What about starlight?

    How is this problem specifically from LEO satellites? I would think that most spaceborn EM radiation is from sources which have been there for eons.

    1. Wellyboot Silver badge

      Re: Starlink? What about starlight?

      Starlink constellation uses a small set of frequencies and provides a near continuous level of transmission with a reasonably small power fluctuation, it's a far better starting point for backscatter filtering than anything else.

    2. thames

      Re: Starlink? What about starlight?

      This was an experiment to show that Starlink satellites in particular could potentially be used as sources of ambient radio signals for passive radar. If there are also other signal sources which could also be used, then that would have to be a different experiment.

  3. 42656e4d203239 Silver badge

    old news...

    Wasn't there a B-2 downed in Croatia/Serbia the other year becasue it was tracked by disturbances in the force (mobile phone towers) and a fair bit of luck?

    I guess if your signal processing is fast enough you might be able to work out a track/target from Starlink scatter in perfect conditions - in practice I think "Eve" will be able to say "oh look it took that route to that target" rather than "it's over there - get it! Quick!".

    1. Xalran

      Re: old news...

      It was a F-117, and it was always following the same flight path in and out of the area... so good old Mk1 eyeballs and a flak cannon were enough to put it down.

      Now the use of telecom towers to track planes has produced several papers, bu so far, officially, nobody has developed a system to use that possibility.

      ( otherwise there's very good chances it would already be in service in Ukraine... just to make sure it works in a real environment )

      1. EvilDrSmith Silver badge

        Re: old news...

        upvoted but a minor correction - it was actually an (obsolescent*) surface to air missile system that was used for the shoot down.

        [*or perhaps not, given it shot down a F117)

      2. Anonymous Coward
        Anonymous Coward

        Re: old news...

        I thought the US lost a stealth bomber over former Yugoslavia because the bomb bay door was open and that made it appear on radar?

        https://en.wikipedia.org/wiki/1999_F-117A_shootdown

        https://theaviationgeekclub.com/an-in-depth-analysis-of-how-serbs-were-able-to-shoot-down-an-f-117-stealth-fighter-during-operation-allied-force/

    2. Brave Coward

      Re: old news...

      One newspaper in my country had quite an excellent cartoon about it, in those days. It would depict two Serbian soldiers, guns still smoking, standing in front of the wreckage and looking quite embarrassed. One of them saying:

      «We’re sorry. We didn’t knew it was stealth.»

    3. ITMA Silver badge
      Devil

      Re: old news...

      Isn't this not too dissimilar to how a group claim to have been able to track Malaysia flight MH370 after it had dropped off radar and effectively "went dark" using WSPR?

      https://www.airlineratings.com/articles/mh370-ground-breaking-report-reveals-location

  4. lglethal Silver badge
    Go

    Conspiracy Theory Time

    The release of this Info comes at a time, when China is starting to release it's own constellation of LEO Comms satellites (i.e. competitors for Starlink).

    By making such claims, China might be hoping to whip up a bit of US congressional hysteria, which might lead to investigations and restrictions on Starlink being imposed, or just hampering their nominal operations for a while. Which would naturally give the Chinese competitors a bit of a helping hand...

    If this had ANY military significance, this paper would not have seen the light of day, since naturally you absolutely dont tell anyone you can track their stealth jets. That would encourage them to go out and build new and better ones. You would keep that Info a TOP TOP TOP Secret...

    1. Alan Brown Silver badge

      Re: Conspiracy Theory Time

      "If this had ANY military significance, this paper would not have seen the light of day, since naturally you absolutely dont tell anyone you can track their stealth jets. "

      On the other hand if the Chinese know that the USA is already doing this (and they probably are), you just punched a hole in their advantage

      We know you know we know you can track our jets and we can track yours

      The problem with "stealth" is that it's always had an (undetermined) expiry date and once rendered obsolete you have a bunch of (hugely expensive) airframes with compromised performance that just lost their primary battlefield advantage

      Incidentally, with "AI" type systems, "stealth" may not be enough. There was a story a long time ago in Aviation Weekly about the new prototype Nimrod systems being asked to scan the ocean and find "anything which doesn't look like sea". It instantly picked up hundreds of fishing net floats and other detritus across several thousand square miles of water - something that was pointed out would be a boon in SAR applications but also works well for ground based systems being asked "show me anything that doesn't look like sky"

      1. I ain't Spartacus Gold badge

        Re: Conspiracy Theory Time

        Alan Brown,

        Stealth doesn't become obsolete, because it's not magic. It's radar signature reduction. Basically it's gaining an advantage over non-stealth aircraft. But how you use it also matters. And that includes the whole environment, including the use of electronic jamming, and planning your flights carefully to minimise your exposure to radars you can't either jam or destroy. It's an expensive tool in the toolbox - but not the only one. Sometimes the best way to avoid detection will be a cruise missile that blows the radar up, or some sort of attack on the target's entire radar network or decoys, or some other thing.

        Short of some change in the laws of physics, stealthy aircraft are going to be harder to kill than non-stealthy ones of a similar type.

        Also harder to counter. They cost more, but if they reduce detection ranges, the enemy now needs to have many more radars to cover a similar amount of sky than they used to. Or leave dangerous gaps in their coverage.

    2. jake Silver badge

      Re: Conspiracy Theory Time

      "If this had ANY military significance, this paper would not have seen the light of day"

      The paper itself has military significance.

      It was written to spread FUD, and probably is specifically targeting the over-reactive, hysterical useful idiots in the US Congress.

  5. Aladdin Sane
    Trollface

    The easy way to know where stealth aircraft are is to wait for shit to blow up with nothing in the airspace.

    1. I ain't Spartacus Gold badge
      Happy

      The easy way to know where stealth aircraft are is to wait for shit to blow up with nothing in the airspace.

      T'his fails for a couple of reasons. Firslty, it's not terribly pro-active. Militaries like to be all can-do!, gung-ho! and all that malarkey. Sounds exhausting...

      Secondly, things might be blowing up because say, you bought your latest batch of pagers from an extremely good new sales guy with some amazing special offers. Or your military base might be near a volcano? Or you have engineers with a tendency to smoke on duty. Or you've annoyed somebody with good special forces troops and they've just paid you a visit.

      Oh, and suicide mice.

      1. EvilDrSmith Silver badge
        IT Angle

        Exploder Lemmings....

  6. xyz Silver badge

    I have oft wondered...

    How much of a "hole" anything flying between my Starlink dish and a Starlink satellite would e-create.

    1. Pope Popely

      Re: I have oft wondered...

      The hole on a single frequency, with 3 objects (transmitter, receiver, reflector) will be caused by the reflector on the surface of one of some rougly egg-shaped space around the line of sight of transmitter and receiver, where the reflected wave arrives at (multiples of) 180° phase shift compared to LOS transmission, causing some cancellation of a portion of the direct wave energy (destructive interference). Several transmitters, same reflector and same receiver at the same time, those possible areas might overlap somewhere. And this is only the beginning. There is constructive interference, Doppler shift, too...

      Best regards,

      about every experienced ham radio operator.

      1. sitta_europea Silver badge

        Re: I have oft wondered...

        "... Best regards,

        about every experienced ham radio operator."

        I was going to mention meteor-spotting but I guess I've been Ninja'd.

        73 de MSEG3

    2. Alan Brown Silver badge

      Re: I have oft wondered...

      It won't. Fesnel calculations apply and the "hole" which needs to be blocked is several hundred metres across at altitude

      (Source: I had to do such calculations regularly in a past like working out microwave propagation profiles. The ones across tidal paths (ie: over the sea) were particularly painful). Interestingly you can use geographical features such as nearby hills to IMPROVE the signal by positioning the antennas such that the antiphase parts of the signal are masked out)

      Add to that that the satellites are moving extremely quickly across the sky and such a hole would only be seen by the antenna on the ground for a few milliseconds at best

  7. STOP_FORTH Silver badge
    Black Helicopters

    GEO tracking

    I heard a rumour about 25 years ago, that Western governments were experimenting with DTH satellite systems. You blanket a country with Ku band satellite broadcasting. Then use the installed base of millions of receivers to report any sudden drops in signal.

    Doesn't matter how stealthy the blighters are, they still leave a fast moving shadow.

    Then it's just Sherlock Holmes analysis. Remove all the shadows due to commercial aircraft. All the remaining holes are military ones. Remove all the holes that show up on radar, then Bob's your uncle.

    Of course, you'd need an amenable broadcaster with modem/PSTN links to all of their STBs.

    I don't even own a tinfoil hat!

  8. HammerOn1024

    Dear China

    It's called EMCON... i.e. EM transmitters are shut off when things are about to get messy.

    1. Alan Brown Silver badge

      Re: Dear China

      Which in itself is a heads up warning

  9. Marty McFly Silver badge
    Facepalm

    Head games

    China: It may be possible, in theory, to track F22's with Starlink, but we don't have the resources to test. So let's just start a rumor.

    US: OMG! They may be tracking the F22 with Starlink!! Let's do some testing.

    Months later...

    China: Hey, we go the results back from the testing done in the US....

  10. Jonathan Richards 1 Silver badge
    Mushroom

    Easy fix

    In any foreseeable situation where the USAAF is trying to fly an F-22 into Chinese airspace without being detected, the proverbial has already hit the fan, and Starlink has been turned OFF.

    1. Tom Chiverton 1 Silver badge

      Re: Easy fix

      As we've seen from Ukraine, any large invasion will coincide with massive malware attacks on infrastructure, civilian or not. I'm sure cable cuts would be in the agenda too.

      Russia barely has a space program, so denying GEO and going full Kessler is probably a win for them...

    2. CowHorseFrog Silver badge

      Re: Easy fix

      The UKR invasion has taught us the age of the fighter plane is over. There have basically been zero fights between UKR and R, because why would there be any ? THis aint hollywood. Both sides want to send bombs to destry the other side, they arent putting on a show for hollywood.

      Fighters are basically useless, its far better to spend the money on missilesand for the cost of the F22, 100 long range missile would do far more damage than a single F22 ever could.

      1. Anonymous Coward
        Anonymous Coward

        Re: Easy fix

        Duncan Sandys' Defence review in 1957 said the same thing. Which led to all the British aircraft manufacturers closing down.

      2. ChrisC Silver badge

        Re: Easy fix

        No, the reason for the lack of dogfights over Ukraine is more due to the nature of that particular war, in particular the limited capability Ukraine has for suppressing Russian surface to air threats, combined with the number/capability of those surface to air systems that Russia is able to field.

        Ukraine aren't going to send their almost equally limited number of fighter pilots and airframes into a situation where they'd be likely to be shot down, unless it offered them a genuinely golden opportunity to strike a serious blow against Russia. Being able to down the aircraft lobbing missiles/glide bombs in the direction of the nearest shopping centre/hospital/school/other targets of similar military value, whilst something they'd dearly LOVE to be doing on a regular basis, is still too risky for the reward on offer, hence why we sadly don't see it happening, and why they're having to deal with that threat in different ways (targetting the missiles after launch, or targetting the bombers on the ground using drones).

        It's also rather important to bear in mind that the Ukraine war is only teaching us things from the specific perspective of a war between two, initially and on paper at least, significantly unequal forces, with limited support from other nations. In another war, fought under different circumstances, the capabilities required may well be quite different. The one thing we CAN learn from previous wars is that we can't predict what the next war will require, which is why presuming that a given technology or capability is now obsolete, dead in the water, a complete waste of time and money to maintain, is a dangerous path to take.

        To take your Hollywood comment - whilst most people might just think of Top Gun as being a work of film-making fiction, being aware that the US actually DOES have a real Top Gun training programme, and understanding what led them to set it up, might in turn help in understanding why it's so dangerous to dismiss things as being of no value in future wars.

        1. CowHorseFrog Silver badge

          Re: Easy fix

          ChrisC: No, the reason for the lack of dogfights over Ukraine is more due to the nature of that particular war,

          cow: Nature ?

          Basically NO dogfights over Iraq 1 or 2, None over Afghanistan, None in Ukraine and barely a few in the Falklands.

          There will never be a dogfight between Russia and NATO or USA and China, because they will be firing missiles.

          So who exactly is going to do dogfights ?

          If you are big enough to have a reasonable Air forec you probbably have missiles which would do a better job. Thats the reality.

          ~

          Chris:

          in particular the limited capability Ukraine has for suppressing Russian surface to air threats, combined with the number/capability of those surface to air systems that Russia is able to field.

          cow: Exact;y so why would there ever be dogfights ?

          1. ChrisC Silver badge

            Re: Easy fix

            "because they will be firing missiles."

            Bear in mind that a dogfight is considered to be any air-air engagement carried out at short range with the aircraft maneovering around one another to try and establish a firing solution against your opponent, or avoid the opponent establishing one against you. Some people might therefore choose to believe that this implies dogfights and missiles are mutually exclusive, but those people would be wrong - once you're close enough such that you can no longer simply point your nose roughly in the direction of the target, pull the trigger and wait for your missile to do its job, then you will want to have at least *some* basic menu of maneouvres available to you so that you can still get into the right position to make use of those shorter range missiles and continue to avoid having it degenerate into a "whites of their eyes" gunfight.

            And even with the advent of more capable short range missiles offering off-boresight targetting, such that you may no longer need to maneouvre into a position where the target is somewhere in front of you, even these missile systems have their limitations, and there will always therefore still be scenarios where, no matter how capable your missiles are, being untrained in the art of dogfighting will put you at a disadvantage. Which is the polite way of saying your life is now in the hands of your enemy being even less competent than you...

            So yes, if you feel supremely confident that,

            your BVR missile systems are capable enough to kill targets regardless of a) how well trained their pilots are in evasive maneouvering and b) how effective their ECM systems might be, AND you're also confident that every air-air engagement will occur within scenarios where use of such missiles is permitted and possible,

            OR if you're then at least supremely confident that, should killing them with BVR missiles be a non-starter for any reason, your shorter range missile systems will then still be sufficiently capable such that you STILL don't need to bother with any of that maneouvering dogfighty nonsense,

            THEN you might, possibly, start to consider that continued investment in dogfight training and weaponry is a complete waste of time and money.

            That's a far easier consideration to be making if you're doing so from the comfort of an armchair as opposed to an ejection seat - I rather suspect that if YOUR life was on the line here, and you were being thrown into a combat scenario where you risked death because someone else had glibly dismissed the need to give you a fully rounded training programme, you might be somewhat more conservative in your expectations re how well the stuff you had been trained on might actually perform in a real world encounter against an enemy whos capablities your own side can only estimate, and who isn't going to want to make it an easy win for you.

            "so why would there ever be dogfights"

            Because the Ukranian Air Force isn't the only one on the planet who may, at some point, end up going up against Russia or an equivalently-equipped adversary. And at least some of the others who may end up having to do it in the future DO have rather better SEAD capabilities either natively or collectively via whatever alliance they'd be operating in at the time, which means their ability to make more use of their own aircraft in the offensive rather than defensive roles is in turn rather better. And as soon as you make it more likely that air-air encounters will take place, it's only a matter of time before you have an encounter where it's something other than a BVR-missile-based turkey shoot with your pilots all making it back home in time for tea having barely broken into a sweat.

        2. CowHorseFrog Silver badge

          Re: Easy fix

          chris: To take your Hollywood comment - whilst most people might just think of Top Gun as being a work of film-making fiction, being aware that the US actually DOES have a real Top Gun training programme, and understanding what led them to set it up, might in turn help in understanding why it's so dangerous to dismiss things as being of no value in future wars.

          cow: yes i know that, that doesnt change the fact that its all a big show for nothing.

          1. ChrisC Silver badge

            Re: Easy fix

            "i know that, that doesnt change the fact that its all a big show for nothing."

            If I promise to stop giving you a hard time over this subject, will you promise to give me the winning lottery numbers for this weekends draw? Because, as someone who must have the ability to see into the future in order to be making such bold claims over the future usefulness of this particular aspect of military training, you'd have no difficulty in providing said numbers, or indeed any similarly accurate details about any other event yet to occur...

    3. CowHorseFrog Silver badge

      Re: Easy fix

      Secondly an F22 doesnt even have the rnage required. From Japan or Taiwan it basially runs out of range before it has too turn around. THeres no way it could possibly hit any actual targets in china. The smart money is to buy lots of missiles.

    4. ChrisC Silver badge

      Re: Easy fix

      You're ignoring the equally forseeable situations where the US (and BTW, unless we've time-jumped back to the 1940's then the F-22 would be wearing USAF, not USAAF, markings...) is attempting to penetrate Chinese airspace after China has set up something for which IT controls the off switch.

      And I'm not talking about them needing to have developed and launched a full Starlink-like equivalent system - all it needs is to have some suitable RF energy being emitted from a suitable relative position to the aircraft being detected - so as we know the Chinese are fond of sticking things on high altitude balloons for example, one might perhaps ponder how many such balloons might be needed to provide an equivalent detection capability if said capability was the *only* thing they were trying to achieve, vs it just being a bonus extra feature of whatever capability the transmitters were actually there to offer...

      1. CowHorseFrog Silver badge

        Re: Easy fix

        chris: You're ignoring the equally forseeable situations where the US (and BTW, unless we've time-jumped back to the 1940's then the F-22 would be wearing USAF, not USAAF, markings...) is attempting to penetrate Chinese airspace after China has set up something for which IT controls the off switch.

        cow: Removing markings from a plane doesnt change the basic fact that fighters do not have the range required to fly from JP or TW to china, destroy some targets and fly.

        Stop talking shit, the problem with fighters is not stealth its range.

        1. ChrisC Silver badge

          Re: Easy fix

          a) The markings comment was just a sidenote - I blame continued exposure to the USAAF name via WW2-era dramas etc. for people still making this mistake despite how long it's been since the first A was dropped from the name.

          b.1) Just limiting ourselves to present-day capabilities and bases, Taiwan to the adjacent coastal region of China is roughly 250km and South Korea to the adjacent coastal region is around 415km. Even if air-air refuelling wasn't an option, then both of those distances are within the publically stated combar radii of several land-based fighters such as the F-22.

          b.2) As we're actually however hypothesising a future war between the US and China, there's no reason to believe the US would be limited to launching strikes from airbases it *already* has access to, as opposed to being able to launch strikes from airbases closer to Chinese airspace that it (either via agreement or by force) has access to *then*

          b.3) Still hypothesising, who's to say we're even talking about flight distances to the *present day* borders of Chinese airspace?

          1. CowHorseFrog Silver badge

            Re: Easy fix

            chris: b.3) Still hypothesising, who's to say we're even talking about flight distances to the *present day* borders of Chinese airspace?

            cow: The western world only has two enemies that really count, Russia and China.

            Who else is there ?

            Both are large countries, technical superiority and stealth dont help, because of range problem.

            There is no-one else to dog-fight, thats a fact.

            Feel free too share with me who exactly is the F35 going to dog fight today or tomorrow ?

          2. CowHorseFrog Silver badge

            Re: Easy fix

            Chris: Even if air-air refuelling wasn't an option, then both of those distances are within the publically stated combar radii of several land-based fighters such as the F-22.

            cow: Refueling ?

            A F22 and an airtanker is close several hundred million.

            THen theres the problem of mating both planes and flying significantly slower during the refuel, posing a significant easier/larger target.

            Why would you risk all that money and people when you fire dozens more missiles .

          3. CowHorseFrog Silver badge

            Re: Easy fix

            Chris: b.1) Just limiting ourselves to present-day capabilities and bases, Taiwan to the adjacent coastal region of China is roughly 250km and South Korea to the adjacent coastal region is around 415km.

            cow: F22 only has a range of 1000kms. So a roundtrip from SK to China is 830km that barely leaves 5 mins of loiter time. If the F22 did try and have a dog fight it would nt have enough fuel to get home.

            Chris: Even if air-air refuelling wasn't an option, then both of those distances are within the publically stated combar radii of several land-based fighters such as the F-22

            Cow: Thats right they only have enough fuel to fly there and back, theres no time for anything else.

  11. Diogenes

    According to Mentour Pilot, they have been able to track MH370 using WSPR, references in the description

    https://www.youtube.com/watch?v=Y5K9HBiJpuk&ab_channel=MentourPilot

  12. steviebuk Silver badge

    Anything that comes from the...

    ....CCP and/or CCP shills/Wumaos is bullshit.

    1. James Anderson

      Re: Anything that comes from the...

      However much you dislike their cruel and authoritarian government you cannot deny that the have one of the richest and technically advanced economies in the world.

      They are pretty good a techie stuff and are improving all the time. Western economies are caught up in short term capitalism that sees real research ( as opposed to market research ) as a waste of money.

      1. CowHorseFrog Silver badge

        Re: Anything that comes from the...

        THeres one thing that the war in UKR has taught us. There is MORE value in having your enemy think and overrate your weapons than actually show them to be a POS as we have seen from R. We all now know their equip from missile defense systems, planes, tanks, ships and everything in between is a joke.

        We can also see from Biden's decision to deny UKR rights to fire AMERICAN missiles into UKR that America also doesnt want a full of display so the world particularly china can see how good or bad their missiles are. SO yes the west is better than R or C, but its not perfect because if it were then Biden would let UKR have full authority.

        1. Jellied Eel Silver badge

          Re: Anything that comes from the...

          We can also see from Biden's decision to deny UKR rights to fire AMERICAN missiles into UKR that America also doesnt want a full of display so the world particularly china can see how good or bad their missiles are.

          Or German, British/French missiles. Or the small matter of 'what missile?'. There doesn't seem to be much in the (known) inventories that could be supplied to Ukraine that they could use, and haven't already used.

        2. I ain't Spartacus Gold badge

          Re: Anything that comes from the...

          We can also see from Biden's decision to deny UKR rights to fire AMERICAN missiles into UKR that America also doesnt want a full of display so the world particularly china can see how good or bad their missiles are

          CowHorseFrog,

          This argument is silly. There's no reason not to believe that the reason the US haven't allowed things like ATACAMS strikes in Russia is their stated one - that they're worried about upsetting Russia and getting escalation. Ukraine are already allowed to use them in Russian-occupied areas of Ukraine, so we already see how they work and Russia will have already captured ones that failed to go off, for analysis. Significant sections of the US government are more susceptible to Russian threats, from what I've read Jake Sullivan (Biden's National Security Advisor) is one of the most cautious.

          There is MORE value in having your enemy think and overrate your weapons than actually show them

          This is probably not right either. Had Putin believed that Russian weapons were rubbish, Western ones were way better, and that we'd give Ukraine those weapons - he might not have started the war. NATO doctrine in the Cold War was to convince the Soviets that we were equipped with good weapons, that we were fully trained to use - and therefore that attacking NATO was a bad idea. Had we armed Ukraine more in 2015 (rather than mostly just giving training) - it would have upset Russia, but might have avoided the war - and for much less than we've spent providing weapons since 2022.

          However, you might not want to get the very shiniest kit captured. It can be learned from and copied. If, for example, we gave Ukraine Meteor missiles to fire from their F-16s - they could introduce a lot mroe danger into Russian air attacks into Ukraine. However, Meteor is expensive, the F-16 probably isn't equipped to operate it and so we've equipped them with cheaper and more plentiful AMRAAM. Sadly with a much shorter engagement range.

          Storm Shadow / SCALP are 20 years old (though they've had updates), and are being replaced with a new system in the next couple of years. That's the latest cruise missile we've given. There are plenty of more modern ones, but again more expensive, more tech to give away fewer spare, and low production rates.

          Two areas where the West have given Ukraine the latest and greatest is in SAMs and artillery. You only fire, relatively simple shells, the guns don't get captured too often. And SAMs being a mostly defensive weapon are harder to capture and reverse engineer. But also Ukraine's need was greatest in air defence and there weren't many alternatives to do the job. Apart from old Hawk batteries, there wasn't a bunch of old but still serviceable stuff to give, so it had to be the best.

          1. CowHorseFrog Silver badge

            Re: Anything that comes from the...

            iaint: This argument is silly.

            cow: Because you are an authority and your opinion is fact ?

            How about you give actual reasons instead of demanding your opinion is right because.

            ~

            spartacus: Had Putin believed that Russian weapons were rubbish

            cow: The answer to WHY Putin believed he would be successful is also answered my observation that its all about perceptions and beliefs and not based on facts.

            I have answered this in another post a week or so back, Putin believed UKR would not fight and simply surrender, just like they did nothing when Russia took Crimea.

            His arrogance was that he never guessed UKR would fight and he never thought there was a chance that his Russian military would be tested.

            Again its all about perceptions not actually measuring or testing the reality of his true strengths or weaknesses. Its all mind games.

            ~

            spartacus: Storm Shadow / SCALP are 20 years old (though they've had updates), and are being replaced with a new system in the next couple of years. That's the latest cruise missile we've given. There are plenty of more modern ones, but again more expensive, more tech to give away fewer spare, and low production rates.

            cow: So what if they are ? F22 are also 20+ years old. These things take time. Nobody is going to deploy a brand new untested major weapon just to be shamed. Even Putin knows this just look at the T14 tank - new and no show, because it would be even more shameful to see it fail.

  13. Anonymous Coward
    Anonymous Coward

    I used to think that radar was pretty simple and that I understood it, having seen it in the movies with an arm sweeping a green circular screen and some dots showing where the enemy are.

    Then I happened upon an interesting looking book in a bargain bin, "How to use radar". It's about how to use small maritime radar sets for navigating small boats.

    It turns out that the reality of using radar is a LOT more complicated than I thought it was. Really interesting read though, even though I don't have a boat or a radar.

    I recommend it to anybody interested in the subject.

  14. CowHorseFrog Silver badge

    Is this the same china that keeps building highways , trains and builders that just fall over every other day ?

    1. O'Reg Inalsin

      All of them?

      1. CowHorseFrog Silver badge

        It doesnt have to be all of them, just too enough ...

        Nobody would go on a plane from any manuf that had too many fails.

  15. Paddy

    Fund me, please!

    "The researchers chose the drone as they estimated it has the same radar signature as a modern F-22 fighter."

    "Is it enough to get further academic funding?", Not "Does it track F-22's"

    1. CowHorseFrog Silver badge

      Re: Fund me, please!

      Thats the chnese government way, bullshit is more important than honesty.

  16. Jaybus

    Other passive sources

    Why rely on Starlink? There's always the sun for passive radiation "disturbance" detection, at least in daylight hours. It is more or less tracking its shadow, or well, somethings shadow, which tells them that something is there, somewhere in the sky.

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