AIS and GPS spoofing


It’s good we have a completely different technology like Loran available to mitigate the effects of this sort of thing. Oh, wait… :frowning:


Wow, that’s pretty scary. This is something entirely different from the kind of spoofing I’ve been talking about. I can’t see how this could be done without a distributed array, which makes it look like the work of a serious actor. I’d also expect the signal source to be relatively easy to DF, and the Chinese do run a pretty tight ship, so there’s another hint pointing straight at them.

I don’t believe in the author’s assessment that this has to do with AIS fakery. Sending a false position stream to your AIS transmitter is utterly trivial, and doesn’t require any falsification of the signal. The greatest difficulty in that is to come up with a believable position stream to begin with, which can be time consuming.

I wonder how far this will go before GPS loses its reputation for reliability? Like I’ve said before, I expect to see increasing incidence of “playful” use of SDR based spoofing. In fact I’m a bit surprised that so few malcreants have adopted the technology after it became commonly available. The time may yet come to dust off that sextant, polish those DR skills, and install a good INS system.

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I can guess of a few ways.

The Russians would transmit a false signal that would cause everyone to show at a same singular place. What about transmitting a false signal that changes to give the impression of movement (in this case a circle)?

Or transmit other ship positions falsely to others. Have a receiver listen for other ships, then repeat their data but in a false position. Maybe repeating their position milliseconds after they transmit their real position, then repeat it more than they do.

These are pure guesses.


There is spoofing other people’s GPS receivers. This is not that hard if you are close enough to them.
Then there is the totally different issue of feeding fake NMEA data into your AIS unit to appear where you are not. Cheap Chinese AIS units that take external NMEA feeds are all over eBay. See this post:

That’s how SDR based spoofing works out (which isn’t just available to the Russians but also the kid next door). It provides a signal that is coherent for a single location. Moving such a position in a circle could account for what we’re seeing, except that the article explicitly states that multiple receivers are moved simultaneously into a circular shape on the map. That sounds a lot like someone is building a local transmitter constellation, which is a pro level advanced move, so to speak. There are severe technological challenges involved (multiple systems in microsecond sync, for one thing), and it provides no benefit over the SDR based method unless you want to hit a large number of receivers at once.

That’s feasible enough, except for the Strava fitness app data, which pretty much confirms this as a case of GPS spoofing.

I was making the point that this is the likely method of choice for illegal sand miners.

What are some reasons to spoof?

  • Fake your own position. (Pretend you are somewhere you are not.)

  • Fake something / ghost ship. (Maybe for fishing to keep ships from your nets?)

  • Fake someone’s position to them. (Defense against smart weapons.)

  • Fake someone’s real position to others. (I don’t know why.)

I can think of a reason for the last one. Fishing boat A “sends” fishing boat B into Canadian waters until the Canadians come out, then move it back just ahead of being spotted. Hilarity ensues and more fish for A.

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Go down to the last post. OMFG that is bad, a whole fictional fleet.

I’ve seen that. AIS on fishing gear.

Well, this essentially gives you a remote control for ships with inattentive crews, so there’s a few usage cases. Like @yacht_sailor points out, you can use it to sabotage the competition. There’s obviously terrorism, as in putting a big ship aground somewhere awkward. Then there’s piracy, as in taking the ship somewhere it wasn’t going. I have heard that you can take a Norwegian Navy frigate pretty much anywhere you want :stuck_out_tongue:

Then there’s warfare scenarios. If you control GPS without the opposition knowing, or with them figuring it out too late, you can win any battle. This is why big resources are getting spent on figuring out new ways.

We haven’t even gotten into all the terrestrial uses for GPS spoofing. Criminal with a foot collar? Mess with The Man all day long. Bad neighbor with an insurance GPS puck thingy? Suddenly he goes speeding at night, parking his car in bad neighborhoods, etc. You have the computer hacking angle that prompted David Robinson to develop the SDR model currently in use. The list just goes on and on and on.

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Also you can have a lot of fun with airplanes, the FAA wants to move away from radar based air traffic control to ADS-B. (same basic thing as AIS)

Inertial navigation systems could help. Units today come in all sizes, costs and duration of accuracy. Found in military weapon systems to high end commercial drones, an INS could alert a ship that its own position doesn’t match the GPS position. A human could then investigate the trouble.

That would work for gross errors, but so would just being somewhat aware that Hawaii is not between Bermuda and Spain.
Civilian grade INS drifts and after a few days a subtle error like being a mile off track is far less likely to be caught as GPS error and the far more likely result is updating the INS from the GPS.

INS is only accurate for 15 minutes or so then needs an update no matter who you buy it from unless the earth and our galaxy stops moving ( correct me if there is something else)
3 of these from Honeywell and some software and you have an INS

Back In the Day before GPS airliners used INS for crossing oceans. It needed to be set accurately at takeoff and would gradually drift during the flight.
"INS accuracy will drift with time; this can occur for many different reasons. Older stabilised platform INS (1970’s and early 1980’s) may have position errors of 2 nautical miles (nm) per hour. Modern strap-down LRG INS tend to have error rates of 0.6 nm/hr. "

There are better units than that shown above, but AFAIK they are for subs and missiles and not sold to the public.

yes I asked some guys what happens over long haul flight and was told the drift still allows the plane to arrive in radar control so they dont care.
6 mile CTE error out LDN to NY I think he told me.
I worked with a guy from a Los Angles class sub, yes they had ins but it was stone age.
One you know the drift a nav computer can keep updating it which is the only way to make it work.
The all have to drift as we are referencing the earth and its moving in space.
The guys going to the moon had to do the same which I think is where they pioneered ins?
Fascinating subject then you realize DP should be based on INS but that will add $100k to the install

The issue is I set my GPS spoof machine to move you 1 mile east. You see the INS being off a mile and unless it is VERY obvious the GPS is wrong, you’ll synch the INS to “fix” it. If I set it 500 miles off you would realize the GPS is the one that is wrong.

maybe but my software monitors acceleration so before it moves it knows the gps update is wrong. Acceleration being the one job INS does very well.
That is one of the reasons it works so well for DP systems to get over multi path jumps when alongside rigs and also for solar issues you get in Brazil and West Coast Africa
The whole reason to pay for INS to is prevent your vessel from following anybodies GPS


From Popular Mechanics this month (behind a pay wall)…

Someone Is Faking the Positions of NATO Warships at Sea. It Reeks of Russia.
…In September 2020, for instance, the Royal Navy’s Queen Elizabeth battlegroup was portrayed as steaming toward the Irish Sea—yet satellite photography confirmed the aircraft carrier and her NATO escorts were nowhere near that area. Between August 2020 and July 2021, researchers discovered more than 100 instances of AIS misreporting NATO warships’ positions, creating a case of “phantom warships.”…

… In one case, the destroyer USS Roosevelt appeared to be sailing four miles inside Russian waters—a grave violation of territorial sovereignty. Of course, Roosevelt was nowhere near the reported location. There seems to be common thread, though. This June, false AIS tracks for the Royal Navy destroyer HMS Defender and the Royal Netherlands Navy frigate Evertsen mysteriously showed the two ships sailing within Russian-controlled territory

…All of the navies victimized by the spoofing belong to NATO or Sweden… Russian military and intelligence services spoof and jam GPS, and AIS spoofing that paints western navies in a bad light is a logical next step. In this case, it’s pretty clear that Russian government forces are conducting the AIS spoofing with a goal of using manufactured data to reinforce propaganda claims against western countries…

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