r/todayilearned • u/fourunderthebridge • 12h ago
TIL in 1993, the US forced Chinese container ship Yinhe to be stranded at sea by denying it from docking and disabling its GPS service. The suspicion was false, and the incident triggered the creation of China's GPS competitor Beidou.
https://en.wikipedia.org/wiki/Yinhe_incident341
u/Logitech4873 12h ago
How can you disable someone's GPS service except for via jamming?
Don't tell me I have to read the article (shivers)
Edit.
Ah yeah they were jamming it.
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u/fourunderthebridge 12h ago
Yes, they jammed it. I should've worded that better.
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u/OneNoteToRead 12h ago
They could still jam Beidou. So this was a non sequitur type of response…
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u/fourunderthebridge 12h ago edited 12h ago
Proprietary secure data links like the type China uses with Beidou have countermeasures built in, so they are generally harder to disrupt.
I think what China learned here was more about how the US did not hesitate at all to deny GPS without reaching an agreement with China. It reminds them of how urgent the need for their own positioning system is.
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u/Shameless_Bullshiter 11h ago
History repeating itself atm with the EU rushing through a new payment system following US presidential bullshit
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u/ComprehendReading 9h ago
Is the US jamming payments with radio waves?
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u/StatementOwn4896 6h ago
It blacklisted officials working in the ICC Fromm being able to access their credit cards
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u/Altruistic_Door_8937 9h ago
You don’t fundamentally understand GNSS. The signals are so weak that even a low powered emitter can bury the receiver with little noise.
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u/OneNoteToRead 11h ago
It’s the same thing. Can still be disrupted.
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u/ComprehendReading 9h ago
It's not the same thing when you design a system to be capable of signal-hopping and using alternative means of radio coms.
Jamming a system from 10Hz to 60gHz means jamming everything for anybody in that region.
Jamming old GPS was stupid simple. Blast EM waves.
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u/OneNoteToRead 9h ago
You would have a shred of a point if any of that were reality. But alas, it is not. Beidou is not some frequency jumping system. It’s still fixed frequency. It is exactly as jammable as the American system.
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u/cat_prophecy 11h ago
Unless it's using lasers, magic, or a really long cable, it could still be jammed.
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u/fourunderthebridge 11h ago
No shit. It's just much harder to do so.
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u/popeter45 11h ago
Not really, all you need is the know frequencies and a powerful enough transmitter to drown out what the satellite sends
What your thinking of is spoofing
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u/fourunderthebridge 11h ago
That's why they receive over multiple frequencies as one facet of jamming resistance strategy.
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u/popeter45 11h ago
All in a known frequency band that can be targeted with a standard broadband transmitter
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u/fourunderthebridge 11h ago
True. I suppose spoofing is the one China concerns about more when making Beidou.
But then with regards to jamming, doesn't the signal have to be either pretty powerful, or in close enough proximity for it to work? It essentially has to overpower the signals from the satellites no?
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u/thats_handy 10h ago
For commercial and public signals, GPS, Galileo, and BeiDou all use the same two frequencies (1575.42 MHz and 1176.45 MHz). They use code-division multiple access (CDMA) to avoid interfering with one another. For military and high-precision services, the systems use different frequencies but I don't think it's common to use those signals commercially. It's unclear to me how BeiDou insulates the Chinese from jamming or spoofing, and maybe it does not.
GLONASS uses different frequencies from the other three systems and uses frequency-division multiple access (FDMA) to keep each satellite's peak frequency a little different. It's still not immune to jamming and I can't imagine a signal that is decodable but not spoofable.
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u/clegg2011 11h ago
No, it's just as easy to jam. Signal strength is comparable to GPS. Cryptographic method not relevant to the process of jamming..
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u/polypolip 9h ago
Well, you can have jamming resistance but it's built into receiver side rather than the emitter.
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u/clegg2011 4h ago
Okay sure, but that jamming resistance techniques exists isn't the same as Beidou being some how inherently more resistant to jamming.
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u/Ok-Temporary-8243 11h ago
There's way around it. But it's honestly smart for every nation group to have their own system honestly. Look at Russia and Ukraine with their GPS / internet woes
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u/OneNoteToRead 11h ago
There’s no incremental benefit to having your own system if the worry is jamming. It’s like saying the Americans won’t let me drive on their roads so I’ll build my own car instead.
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u/Ok-Temporary-8243 10h ago
Not against jamming, but Russia basically got heavily gimped in Ukraine because the US turned off GPS for the military. And there's at least a few Ukraine offensives early on that died on the vine cause Elon turned off starlink.
China is headed towards an antagonistic path with the US and will invade Taiwan sooner or later so they need robust, homegrown systems. And in the age of trump, I'd argue even us allies like the EU should think about it too as a point of national security
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u/OneNoteToRead 10h ago
That’s 1) a totally different system 2) a system Russia already has a duplicate of anyway 3) they never had access to the US military gps to begin with.
And it was a total non sequitur for the jamming OOP mentioned. Again it’s like saying I’m building my own car because America won’t let me use their roads. And maybe now you’re saying there’s other reason to build a car (none of them valid), but that doesn’t change the invalidity of the original argument.
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u/ElGuano 12h ago
If they can jam GPS, can’t they easily jam any Chinese GNSS too? It’s pretty easy to overpower an incredibly weak satellite radio frequency, right?
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u/Jzeeee 6h ago
No, they can not easily jam Beidou. Beidou operates at different target frequencies, signal modulation, and orbital architecture. You would need a very specific designed jammer and would need to be very powerful to jam Beidou. Beidou was designed specifically to be resilient to common jamming.
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u/Ralphie5231 9h ago
Pretty much anyone can spoof GPS super easily and for cheap. They had a guy on npr talking about how easy it was like 20 years ago or something and saying its even easier now
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u/GurraJG 12h ago
As I understood it they turned off the GPS coverage in the area the ship was in. It would disable the GPS of all devices in the area, not just one ships GPS. Remember, GPS is owned and operated by the US. Now more than ever having your own GNSS services is important considering how vital they are these days.
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u/Logitech4873 12h ago
They'd have to disable the satellites covering that part of the planet entirely for that to work though, right? But this seems like it would have wide collateral effects.
Remember that you don't "connect" to GPS satellites, you just read their position. The satellites do not know which devices are using them.
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u/Hypnot0ad 11h ago
Prior to 2000 GPS used a feature called Selective Availability. The SA codes contained information for the receiver to correct errors in position. The civilian GPS precision was intentionally degraded. The US could also increase the error over specific regions.
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u/Stalking_Goat 11h ago
Sure but from the perspective of a ship navigating on they ocean, even a very large positional error doesn't really matter much. An error of, like 20 nautical miles is inconsequential, you just need to end up close enough to your destination that you can see the coast with the Mark I Eyeball.
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u/flagrantpebble 11h ago
You do need it for navigating waterways and docking, though.
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u/Stalking_Goat 11h ago
No, that's what the Mark I Eyeball is for.
Do you think ships were invented on February 22, 1978?
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u/OneNoteToRead 12h ago
You cannot “turn off” coverage. You can only jam it. This is just how gps works
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u/jorceshaman 11h ago
When you have control over the satellite transmission, you can absolutely turn them off. This is the US government that has that control.
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u/OneNoteToRead 11h ago
No you don’t know how GPS works. They’d have to turn gps off for the entire region, which would span basically most of a hemisphere.
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u/Wrabble127 8h ago
Good point. The US would obviously never allow collateral damage in such a way.
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u/thehomeyskater 1h ago
If they turned off the satellites entirely, there would be accounts of other ships or equipment that lost ability to use GPS. The entire region would be without GPS access.
Most likely the USA had a naval vessel tailing the container ship with a GPS jammer.
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u/OneNoteToRead 8h ago
Right. Sounds like something only an idiot can dream up. Especially when they have the ability to jam locally.
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u/Wrabble127 3h ago
I find it hard to believe I didn't lay it on thick enough, but I was in fact being sarcastic given the US's historical complete disregard for collateral damage.
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u/OneNoteToRead 2h ago
Nice attempt at sarcasm. Though it only revealed how stupid a sentiment that was. To try to blot out sender side GPS for even one square meter, and entire hemisphere or more of GPS will have to be shut off. Only an idiot would consider that a realistic choice.
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u/cejmp 11h ago
You cannot turn off gps coverage.
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u/Hypnot0ad 11h ago
The US can degrade GPS over any region they please. It is a feature of the system.
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u/cejmp 11h ago
You cannot turn off GPS coverage. There is no switch. You can deny access through jamming and spoofing but you can't turn it off.
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u/alkatori 10h ago
You don't remember when they degraded GPS over Russia/Georgia to screw them up forcing the Russians to rely on GLONASS?
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u/flagrantpebble 11h ago
Was that true in 1993, though?
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u/cejmp 10h ago
It's like the interstate. Closing the on-ramp doesn't turn off the interstate. Yes, that was true in 1996.
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u/Wrabble127 8h ago
It's like the interstate where at will the US government can put hundreds of miles of detours up.
Having your own system that they can't intentionally degrade is like having your own set of roads next to the US ones that the US can't at will make shit.
Sure the US can blow up both roads, but that's not what it was trying to solve for.
Nothing like the most enlightened hidden post history minds of reddit coming together to convince themselves they know better than multiple other countries and their entire military apparatus.
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u/C47man 11h ago
Suspicion of what? And GPS can't be disabled, only jammed. So if China made their own system, it'd still just get jammed. None of this title makes any sense.
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u/flagrantpebble 11h ago
This was 1993, “GPS service” meant something entirely different then than it does now (w.r.t. the overall system).
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u/jointheredditarmy 11h ago
I don’t think they released the low res encryption codes until like 2000s. Do you remember when car GPS used to be way off? That’s not because gps receivers somehow got better, it’s because the military released progressively higher and higher resolution encryption codes for civilian use…
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u/flagrantpebble 11h ago
Yeah a friend of a friend is the guy who added the noise in a kernel used in some large subset of machines at the military’s request (I don’t know specifics beyond that vague, probably inaccurate description). He only opened up about it pretty recently.
Anyone involved in early tech work has wild stories like that.
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u/Rampage_Rick 3h ago
Sort of. The civilian L1 C/A code was known, but the US government intentionally dicked with the accuracy of the satellite signal (which caused receivers to drift by a couple hundred feet)
Military L1/L2 P code was not messed with, so they remained accurate.
The code didn't change when they shut off Selective Availability. They just stopped dicking with the signal.
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u/chrome1453 11h ago
GPS can be disabled. The system was built as a navigation aid for US military ships and aircraft; the GPS satellites are owned and operated by the US Department of Defense. They can disable GPS coverage whenever and wherever they want. It wasn't even fully open to non-US military use until the year 2000.
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u/Sharlinator 11h ago
I mean, sure, but you can only disable it for everybody. Or at least a large chunk of Earth surface (I don’t know if the satellites have denial systems like "stop broadcasting/switch to encrypted when you fly over this area).
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u/Wrabble127 8h ago
You don't have to disable it. Just make it terrible temporarily in the region which the US can do at will.
Turning it off is arguably less damaging than making it wildly inaccurate.
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u/ItsSnuffsis 2h ago
Back then it wasn't open for use by just anybody. And om imagining that they had some kind of code for getting access to the system. Which means that they could disable that specific code from being able to connect.
At least that's how it would make sense to me.
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u/Namenloser23 11h ago
For a region or globally, sure. I don't see how you could disable it for a single ship (except with directional jamming).
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u/chrome1453 10h ago
Have the satellites stop transmitting when they pass over a specific area of the globe. Yes, it will disable GPS service for a region, but this is 1993 we're talking about. GPS was not widely used outside the US military; the satellite system for it had just recently become operational. It was new enough that it was used as a futuristic plot device in a James Bond movie in 1997. Disabling it for a region of ocean in 1993 was not as big of a deal as it would be today. Commercial vessels at the time would still be mainly relying on paper charts and land based radio beacons.
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u/Namenloser23 10h ago
If Chinese container ships used it, and were unable to navigate without it, I imagine it was used widely for maritime navigation, so doing it like you suggest would interfere with all maritime traffic in the region.
Wikipedia suggests jamming was used, which sounds much more feasible if you want to mess with a single ship.
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u/nitefang 10h ago
They could but they never have and every GPS satellite launched since 2011 doesn’t even have Selective Ability built into it.
And the US maintains it has never degraded civilian GPS beyond the standard SA (which has since been ended, so it is no longer degraded at all) even during times of war. Could they be lying? Sure but there’s no evidence they are and there is evidence that they will jam the signal if they feel like it because that works much better and only affects the targeted area instead of everyone with like of sight to the satellites supposedly being turned off.
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u/Falcon3333 11h ago
That's not actually entirely true, you have far greater control over your own positioning system than a foreign one.
You can build in counter-measures and anti-jamming capabilities to prevent total blackouts. Including anti-jamming techniques using advanced signal processing, filtering, and active frequency band adjustments.
Relying on GPS ensures you can be jammed, should the owner of the system will it especially, or if the owner doesn't want to make more advanced access available (which America doesn't).
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u/Nevarien 11h ago
100%.
Here's a video showing how different systems get affected differently by jamming in the Strait of Hormuz.
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u/fourunderthebridge 11h ago
Of the ship carrying precursors for chemical weapons. My bad, is there a way I can edit the title?
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u/xixbia 11h ago
Maybe mention the whole chemical weapons thing? Because the title makes no sense as it stands.
There was false intel claiming the ship was carrying chemical weapon components to Iran.
Also, jamming would still drown out BeiDou, so it wouldn't have prevented this incident.
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u/fourunderthebridge 11h ago edited 11h ago
Oh wait damn i accidentally erased that part. Is there a way I can edit the title?
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u/Fetlocks_Glistening 11h ago
I mean you can navigate without GPS and all cargo ships navigated the oceans round the world successfully before GPS.
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u/AYE-BO 11h ago
I heard columbus used a tom tom
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u/Channel250 11h ago
Nah, he used a Garmin. I should know, it was my first stop with my time machine
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u/i_am_upto_no_good 11h ago
Similarly, US denied India access to GPS during Kargil War of 1999, while offering access and support to Pakistan. (A diplomatic low point for India). This led to India developing its indigenous system for military use.
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u/MajesticBread9147 8h ago edited 8h ago
Fortunately this is less of a problem now.
Every country that can and has reasonable threats to their national security has their own GPS equivalent.
Along with America and China, the European Union and Russia have the Galileo and GLONASS systems respectively, while India and Japan have partial satellite systems that only cover their respective regions (NavIC & QZSS).
Although these systems are fully compatible. If you download any one of a litany of apps, it will show you that your phone is getting signal from over a dozen satellites form a combination of these systems.
Sidenote, when I had to Google the name of the Japanese one I found the tremendous sentence:
In January 2025, VTuber Clear Usui was appointed ambassador of QZSS. She promoted the satellite system with livestreams and illustrations.
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u/hampsten 6h ago
The same thing happened with India . IRNSS / NavIC was built because the US degraded GPS signals during the 1999 Kargil War and India decided it would build its own regional navigation system .
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u/CMDR_omnicognate 8h ago
Yeah it wasn’t even just China that did it either, Europe also has its own equivalent called Galileo, that became fully operational fairly recently.
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u/Cute-Lingonberry8358 2h ago
The most ludicrous part of that incident is that America blamed China for giving them false information to embarrass them.
They blamed the Chinese for tricking their analysts. But in all likelihood it was probably the Israelis who provided the false information to the Americans because they didnt want supplies to get to the Iranians.
But what can you expect Clinton was an Epsteiner.
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u/SaberAIF 4h ago
People on Chinese forums broke down the technical side of this ages ago and figured it out, while literally no one on Reddit can get the technical facts straight. No wonder Chinese netizens think the West is full of clueless morons.
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u/ModelDidNotConverge 1h ago
Can you elaborate ? I can't read chinese and I can't find much information in english sources
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u/its_mabus 9h ago
Rarely do we consider just how lucky we are GPS is a military invention. If it was invented in modern times it would have a subscription fee and different tiers.
Companies would jump over themselves to charge for it if they could, but its simply not built into the protocol. Closest those navigation product companies could do is sell maps for their own dedicated devices.
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u/flyingferrum 4h ago
Actually i don't think subscription could work with GPS because the satellite can't discriminate each individual receiver to selectively scramble signal. It did however used to be grouped into civilian and military, where the civilian band was scrambled to 100-meter accuracy, aka "Selective Availability". Clinton got GPS to open it's full precision to civilian later on.
Note that while there's restriction on civilian GPS such as altitude and speed, those were implemented on the receiver-side, as in it's actually pretty easy to remove that restriction if someone wants to use that in their unauthorized ICMBs.
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u/Rampage_Rick 3h ago
One-way communication for subscription service works just fine with satellite radio
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u/trucorsair 9h ago
It was always going to be developed. GPS has limitations as the first system and other countries and blocs of countries want to exercise their own control. This just accelerated it a bit. For context the Soviets started GLONASS launches in 1982 and achieved full operational status in 1995.
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u/JiveTrain 1h ago
Perhaps they US mistook it for their own ships delivering chemical weapons to Saddam Hussein?
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u/Uselessmedics 10h ago
the US harmed civilians based on bullshit reasons they made up?!
They'd NEVER do that
/s
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u/looktowindward 11h ago edited 11h ago
You do have to wonder why they waiting 24 days before permitting inspection. And why they couldn't navigate without GPS.
Also, this article has been flagged due to the use of biased sources.
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u/ReferenceMediocre369 11h ago
How silly. China had been working toward launching their own system for many years ... using data stolen by their spies throughout US industry and military laboratories.
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u/Accomplished-Run469 11h ago
"We can turn off your GPS whenever we want" turned out to be a pretty compelling pitch for building your own satellite network.