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North Korean ICBM launch detected using GPS
- dontbenebby 4y ago>Missiles make ionospheric disturbances that GPS records. The yellow ripple is the ionospheric disturbance. Where can I read more about the meta level concept of "isopheric disturbances"? (Because I suspect I'll find this has been done by military intelligence for a long time then rediscovered by so called "arms control" wonks who insist on putting their code into the public domain.)
- teeray 4y agoHam radio is actually where you’ll find a lot on the subject. “Band conditions” are determined by the amount of ionospheric disturbance present. For example, meteors entering the atmosphere produce a disturbance that can reflect radio—there are ham radio techniques that exploit this to communicate.
- krisoft 4y agoThe second tweet in the linked thread links to the paper which inspired them: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL078088 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... > who insist on putting their code into the public domain You say that as if there is something wrong with that.
- InCityDreams 4y ago" /s", spotted on my end.
- dontbenebby 4y ago>You say that as if there is something wrong with that. So to be clear, you an arms control expert public domaining code that aids totalitarians like Putin and the North Koreans has... "nothing wrong with that"? Some domain specific knowledge was meant to be esoteric* and there are a variety of better licenses such as CC-non-commercial that allow peaceful uses of the code without allowing it to be used by literally anyone on the planet. (*Unless you pay the proper fees, of course. But that's not just about money... you have to earn the right to make the purchase.)
- Dylan16807 4y agoI do not feel bad about indirectly aiding them with well-after-the-fact missile trail detection. Why should I? Why should this be difficult to do? It can be called "military" but it doesn't help with offenses and doesn't really help with defenses either.
- dontbenebby 4y ago>well-after-the-fact missile trail detection. Sorry, I missed that bit, I thought this could also be used to detect incoming missiles. I do not want my enemies to be able to detect incoming missiles. Sorry for posting so angrily.
- kadoban 4y agoTo do anything about incoming missiles, you'd need extremely low latency tracking, integrated into whatever system you're using anyway. Not sure exactly you'd be worried about even if this was near-real-time.
- rosnd 4y agoYou could probably use techniques like this to rig an early warning system on enemy territory, but there are of course better options.
- thot_experiment 4y agoWild! I don't think I've ever seen someone who thinks restricting tech like this is actually a good idea. I thought that was just like, crazy government people who don't understand technology. I'd hoped we'd moved past printing the entire code of PGP in a hardback book in an OCR font but I guess y'all still out here.
- dontbenebby 4y agoI literally had a bronze bust of JFK on my desk on k street. I’m not a government type unless I’m calling people my long haired opponent ala Hunter S Thompson running for mayor
- Xylakant 4y agoIf you follow the thread, there’s a link to https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL078088 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... which contains this introduction: ======== It is widely recognized that rocket launches can be an anthropogenic source to trigger traveling ionospheric disturbances (TIDs) by generating acoustic-gravity waves (Afraimovich et al., 2002; Arendt, 1971; Bowling et al., 2013; Calais & Minster, 1996; Chou et al., 2018; Ding et al., 2014; Kakinami et al., 2013; Li et al., 1994; Lin et al., 2014; Lin, Chen, et al., 2017; Lin, Shen, et al., 2017; Noble, 1990). The rocket-induced long-distance propagating TIDs associated with shock/ducted gravity waves and internal gravity waves were observed by using Arecibo incoherent scatter radar (Noble, 1990) and ground-based Global Positioning System total electron content (TEC) observations (Calais & Minster, 1996). Lin, Shen, et al. (2017) first reported the rocket-induced shock waves and concentric TIDs (CTIDs) subsequently using Global Positioning System TEC over California-Pacific region. They suggested that the CTIDs are the manifestation of concentric gravity waves that were originated from the mesopause region. ==== The effect seems to be proven quite a while ago. Using GPS receivers to make that widely accessible seems to be new, but I honestly doubt that military intelligence would rely on that - I’m confident they have more direct methods to detect launches such as (radar) satellites.
- EmilioMartinez 4y agoWhat does "gravity waves" mean in this context?
- yongjik 4y agoProbably this? https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave Not to be confused with https://en.wikipedia.org/wiki/Gravitational_wave https://en.wikipedia.org/wiki/Gravitational_wave
- krisoft 4y agoHere is the code which generated the linked video: https://github.com/tylerni7/missile-tid https://github.com/tylerni7/missile-tid
- amelius 4y agoI'd like to see the amount of false positives/negatives, rather than just data of one day.
- krisoft 4y agoThey don’t really seem to have a detector. They have a thing which makes visualisations, and it seems it should be possible to build a detector on top of that, but that doesn’t seem to be done yet.
- tylerni7 4y agoOh hey I wrote this! Yeah, we had a detector with some ML stuff, it worked okay, but the main issue is there isn't much training data. Overall the false positives are quite low (visually, which is hand wavey, of course). I've not really seen a big event that was not real. I ran it for a while 24/7 and while there are "scintillations" there aren't any circular waves. False negatives are a much bigger issue. Something like an IRBM or SRBM doesn't really show up, and those are much more common. Fwiw, this uses a bandpass filter to look for the ripples, which filters out a ton of noise. Looking at ionospheric depletion would be good and probably more sensitive, but it requires accurate models of what the ionosphere ought to do. I've tried a few things there with mixed results.
- krisoft 4y ago> Oh hey I wrote this! I’m amazed by your project. Thank you for sharing it with us.
- beardyw 4y agoIs it possible someone could explain as if to a small child what data can be collected from GPS which shows this effect. I don't understand.
- chmod775 4y agoI don't think I could explain it to a small child, given that I don't have a great understanding of it myself. But here's what I could scrape together based on a linked paper[1]: You use GPS receivers to detect ionospheric disturbances. Ionosphere, coming from the word "ionized", means it consists of charged particles, positive or negative. (Missile) exhaust is mainly neutral molecules, creating a "hole". These ionospheric holes can be detected through the Faraday Effect[2]. By measuring the Faraday rotation of radio signals (like GPS), you can detect these holes. I think this is similar to how polarized light 3d cinema systems work, except it's the radio spectrum instead of light. [1] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010JA015531 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... [2] https://en.wikipedia.org/wiki/Faraday_effect https://en.wikipedia.org/wiki/Faraday_effect
- krisoft 4y agoGPS signals go through the ionosphere on their way from the satelites. The ionosphere causes distortions in the signal. If you want to achieve the best navigational accuracy you need to account for these distortions. These distortions are not constant. They change from time to time. There are many different ways to account for them. One of the most accurate solution is to keep a GPS receiver on a well known location. Since you know that this receiver haven’t moved you can use the signal measured to estimate the parameters of the ionosphere between that station and the satelite. Normally these signals are used to correct GPS navigational solutions. You take the closest station to your moving receiver and assume that whatever way the ionosphere was distorting for that station will do the same for your receiver too. This is valuable so there are network of such GPS stations in a lot of places. Here they use the data collected by these stations differently. Instead of correcting a navigational solution they visualise the measured state of the ionosphere as seen by a bunch of these stations.
- 4y ago
- H8crilA 4y agoIsn't the ionosphere already past the burn-out phase of a ballistic missile? I.e. by the time the rocket gets there it is just a glorified harpoon. Or perhaps that doesn't matter as anything of this size travelling at this speed would cause detectable disturbance?
- perihelions 4y agoRelated: last month's [0] gamma-ray burst also had interesting, measurable effects on the ionosphere, https://gcn.gsfc.nasa.gov/gcn3/32744.gcn3 https://gcn.gsfc.nasa.gov/gcn3/32744.gcn3 ("GRB221009A: Detection as sudden ionospheric disturbances (SID)") https://www.qsl.net/df3lp/grb221009/KLM_grb221009a_magnitudes.png https://www.qsl.net/df3lp/grb221009/KLM_grb221009a_magnitude... (from the above link) http://abelian.org/vlf/grb221009a-DHO.png http://abelian.org/vlf/grb221009a-DHO.png http://abelian.org/vlf/grb221009a-NAA.png http://abelian.org/vlf/grb221009a-NAA.png http://abelian.org/vlf/grb221009a-NSY.png http://abelian.org/vlf/grb221009a-NSY.png [0] https://news.ycombinator.com/item?id=33215572 https://news.ycombinator.com/item?id=33215572 ("Record-breaking gamma-ray burst possibly most powerful explosion ever recorded") This was detected with VLF radio, but I wonder if this kind of event also has an effect on GPS signals? The time-of-arrival of astrophysical gamma rays isn't uniform across the earth.
- ransom1538 4y ago
- rafael09ed 4y agoThat question implies that they couldn't land a nuke in Japan or South Korea currently. I think their current rockets have that capability.
- germinalphrase 4y agoThey do - but that’s only part of the risk. The logistics around nuke delivery is more complicated (or course). For the interested: “Arms Control Wonk” podcast and blog with Jeffery Lewis and Aaron Stein are good resources.
- mikeyouse 4y agoThey very likely already have that.. they’ve detonated >50kt nukes and have mobile ICBM launchers that have demonstrated rockets with thousands of miles of range. They could almost certainly detonate a nuclear weapon in Korea or Japan. I’d put even odds on a strike on Guam, but probably not quite capable of hitting Western US.
- NikkiA 4y agoThey've put stuff in orbit before, so I'd wager they could hit the continental US, but probably without any accuracy beyond maybe picking a state.
- ilyt 4y agoThat's one of most impressive examples of essentially "passive radar" I"ve seen!
- darepublic 4y agoAfter-effects of WW2 still posing existential threat to us all..
- gregfjohnson 4y agoWhat I wonder about is all of the technologies that go into ICBM's with nuclear weapons. My layman's guess is that there is active support and collaboration of the NK nuclear program from outside. North Korea is a headache for the US and other western powers, one more thing to consume policy bandwidth and military preparedness. This would seem to be in the interests of China and Russia, and perhaps others. I don't worry too much about the threats that periodically emanate from North Korean; if they start to exceed their utility from the perspective of China and Russia, the needed resources to maintain a viable nuclear program can be quickly shut off. I do hope that I will live to see a "1989" moment in which the North Korean regime is overthrown, and relegated to a horrible and sad footnote in human history.
- laurencerowe 4y agoWhile Russia and China don’t want to see North Korea collapse as existing nuclear powers they don’t especially want to see other countries acquire nuclear weapons. Active support and collaboration came from Pakistan, Iran and Libya who were all trying to develop nuclear weapons of their own. https://rusi.org/explore-our-research/publications/commentary/aq-khan-dead-long-live-proliferation-network https://rusi.org/explore-our-research/publications/commentar...
- walrus01 4y agoGoogle "aq khan pakistan north korea" https://www.google.com/search?client=firefox-b-d&q=aq+khan+pakistan+north+korea https://www.google.com/search?client=firefox-b-d&q=aq+khan+p... https://en.wikipedia.org/wiki/Abdul_Qadeer_Khan https://en.wikipedia.org/wiki/Abdul_Qadeer_Khan Yes there was a great deal of outside help with their enrichment and weapons design.
- aredox 4y agoBoth nuclear weapons and ballistic missiles are technologies from the 1940's. They don't need outside help.
- spookie 4y agoWell, these are multiple times more powerful. Not exactly last century's tech. There are other factors too, like the sanctions these countries are under. One might say that some friendships were harnessed over common enemies, but I digress.
- noobhack 4y ago
- jjk166 4y agoFun fact: the arecibo radio telescope was funded to study ionosphere disturbances so the US military could explore the possibility of detecting ICBMs passing through the ionosphere. To my knowledge no such system was actually built but apparently it wasn't as ridiculous a proposal as I thought.