back to article Sad Nav: How a cheap GPS spoofer gizmo can tell drivers to get lost

Researchers have developed kit that masquerades as GPS satellites to deceive nearby GPS receivers and thus potentially trick drivers into heading off in the wrong direction. The team – a trio of groups at Microsoft, Virginia Tech in the US, and the University of Electronic Science and Technology of China – detailed in a paper …


  1. DougS Silver badge

    You could get around this with dead reckoning

    Doesn't need to be super accurate, just enough that you can't suddenly move miles away from your previous location. I suppose an attack that slowly and subtly changed your "location" would still be possible if it stayed below the detection threshold of the dead reckoning hardware, but that would require an attacker be pretty close for quite a long time - increasing the chance of detection.

    Probably would also help if cars used somewhat directional antennas that only looked up (or rather, not horizontally) While technically GPS satellites can be used anywhere above the horizon, in practice its designed so you don't need the ones that are very low on the horizon so throwing out results that are less than 10* above it should be fine. Then you'd just need to worry about attackers following you in a drone...

  2. MNGrrrl

    Easy solution

    Modern cell towers use beam forming. There are numerous apps already out there which can navigate by non-GPS means, usually to an accuracy within 20 meters. It's enough to say what street the device is on, just not which building. This is *not* difficult to do. accelerometers are indeed not reliable *unless calibrated*. The very same sensors in cell phones are used in inertial guidance systems on planes. They're not accurate enough to be used for reduced separation approaches but they'll get a plane lined up on the ILS even if GPS is completely out from takeoff to approach 700 miles away. A car won't have the same accuracy due to sudden high g-forces from vibration (like driving over a pothole), but combined with trilateralization it will be accurate enough to navigate the roadways and distinguish between parallel roads.

    1. werdsmith Silver badge

      Re: Easy solution

      A car won't have the same accuracy due to sudden high g-forces from vibration (like driving over a pothole)

      Not done much flying in smaller aircraft in rougher weather then ?

    2. Anonymous Coward
      Anonymous Coward

      Re: Easy solution

      Fairly sure they are not the 'very same sensors' - INS sensors are at least 2 or 3 orders of magnitude better than your phone. There was a nice write up of a couple of guys trying INS on a phone They had drift of several metres a minute with the device stationary on a desk, so better hope that ILS approach you need to hit to 20 metres is no more than about 5 metres away.

    3. theModge

      Re: Easy solution

      With good quality sensors (i.e. better than is in a phone) it's possible to be really very accurate with a combination of accelerometers and gyroscopes. ~1m accuracy in the applications for which I've seen them used.

      1. TRT Silver badge

        Re: Easy solution

        My vehicle already uses wheel rotations and steering wheel angles to work out where it is along with the GPS signal. It increases the accuracy of the system to the point where I found I could drive (albeit it incredibly slowly) using the turn countdown indicator at night in a sudden fog so thick that you could only see a car length ahead. It was enough to get me onto a side road where I knew I could find a space to park up until the fog thinned a bit a couple of hours later.

  3. Haku

    Thanks for the tip off.

    I'll be sure to make & use one when I 'borrow' vehicles with GPS trackers.

    1. Anonymous Coward
      Anonymous Coward

      Re: Thanks for the tip off.

      Meh, overkill. A cheap Chinese GPS jammer will achieve much the same for a tenth of the cost.

      1. Haku

        Re: Thanks for the tip off.

        A GPS jammer just makes it 'disappear', a GPS spoofer could send them on a wild goose chase round the M25 on a loop.

        1. CrazyOldCatMan Silver badge

          Re: Thanks for the tip off.

          wild goose chase round the M25 on a loop

          Or, more accurately, a slightly-annoyed-duck stop-and-start round the M25..

          (Anyone else remember the old days when people could use the M25 for illegal races to circumnavigate London? I suspect they'd be lucky to get 5 miles now..)

      2. CrazyOldCatMan Silver badge

        Re: Thanks for the tip off.

        A cheap Chinese GPS jammer will..

        ... end you up in $LOCAL_PRISON if you get caught..

    2. Anonymous Coward
      Anonymous Coward

      Re: Thanks for the tip off.

      Handy if you have one of those insurance black box trackers too - just set it to show you never exceeding speed limits and driving like a saint.

  4. Shadow Systems Silver badge

    I thought this was another Microsoft story...

    My screen reader said "sad nav" as if it were "SatNad" (the popular euphamism for Microsoft's big cheese) & all I could think was "MS renders something else FUBAR, so what else is new?" Then I RTFA & realized my error in parsing something, forced a character step through the title, & found out where I went wrong. Still, dodgy receivers, obscenely easily hacked devices able to be spoofed with an R'Pi, & user's lives being given ulcers... That sounds like about right. =-J

  5. ida71u

    Self Drive Cars ! Yeah Right :(

    So GPS jamming can be built for (or possibly even with) Peanuts ! Now you can have GPS diversion control. And they want to introduce self driving cars that rely on GPS for location info & routing, even if its not strictly necessary for it to move ! I can see the sh!ts & giggles coming that sitting on a city street corner with either a jammer or a diverter will cause for any teenage miscreant that wants a bit of fun while watching the hapless autonomous vehicles driving in circles, with a passenger that has no control. Priceless :)

  6. Giovani Tapini

    To be honest

    My experience of sat nav's is that they do this all by themselves from time to time, without all that tedious mucking about with Pi's.

    I have been told I am driving in Brussels while driving in the UK countryside. I have seen it stall (usually just before a complex junction) and resurface just in time to tell you to do a U turn. In some cases almost maliciously sending me down a road only to come back past it later.

    Anyone who trusts their computer blindly will be the one parked on the railway track...

    1. Christoph Silver badge

      Re: To be honest

      A friend woke up one morning to find that according to his satnav his house was doing several hundred miles an hour across the North Sea. Though that was the morning after the 9/11 attack so probably intentional scrambling.

    2. CrazyOldCatMan Silver badge

      Re: To be honest

      I have been told I am driving in Brussels while driving in the UK countryside

      Manchester City Centre has some interesting GPS blackspots (or did 5 years ago) - one of which caused my GPS to insist that I was suddenly in Leeds..

  7. Spanners Silver badge

    James Bond had one of these

    In "Tomorrow Never Dies", a dodgy newspaper owner uses one of these things. That character was a mixture of the late "Sir Bob" and some dodgy Australian dude.

    Sir Bob is no longer around but we need to make sure that the other guy never lays his hands on one of tese things!

    1. Aladdin Sane Silver badge

      Re: James Bond had one of these

      It did give us Teri Hatcher as a Bond girl, so, y'know, swings and roundabouts.

  8. Thoguht Silver badge

    Built-in car satnav systems only use GPS as a sanity check, they mainly use the inputs from the road wheels and electronic compass.

    My old car had persistent problems with water getting into the antenna assembly and rusting things up, so I was completely without GPS signal on several occasions. Did it make any difference? None at all if you were in a city because every time you turn the system is able to recalibrate your position.

    1. Anonymous Coward
      Anonymous Coward

      Are you sure? I can't find any references to this actually happening? I think most car sat navs are basically just sat navs - the clever bit is the 'sanity check' inherent in the built in software and maps that keeps you locked to roads.

      1. Baldrickk Silver badge

        I don't know about "Mainly" but our Discovery 3 falls back on inertial guidance when it loses GPS.

        It's accurate enough to show your rough position while in a tunnel, or get you past a junction in a black spot, but the accuracy degrades pretty quickly beyond that.

        It fixes itself once it starts getting updates from GPS again.

        1. Anonymous Coward
          Anonymous Coward

          I bet it doesn't use INS - I think it probably just uses an 'if road = tunnel then {assume I'm moving at the same speed along the road I was on when I lost sat nav signal}" function

          1. onefang Silver badge

            "'if road = tunnel then {assume I'm moving at the same speed along the road I was on when I lost sat nav signal}"

            Which wont work too well in the labyrinth of roads under the city centre where I live.

  9. Eclectic Man

    Knowing where you are is not the same as not being lost

    I worked for a large company in a building next to the M3 motorway in Hampshire, England. We had visitors who would drive there for meetings, and we always told them NOT to use SatNav but to follow the map we sent them. Otherwise they would get the message "You have reached your destination" as they drove past the site on the M3, to much consternation on their part. Frankly it should have been in a Mr. Bean film. It usually took them another half hour to negotiate the minor roads from the next motorway exit, taking directions by phone.

  10. Mystic Megabyte Silver badge


    I picked up a hire car at Cardiff airport at night and wanted to go west. I had imagined that I would be on the motorway pretty soon but it was not to be. The SatNav took me down single track lanes and I'm sure at one point I went through a farmyard! However it got me to my destination OK.

    P.S. Going west on the M4 near Cardiff there's a big sign saying "Cardiff International Airport".

    Going east there's a sign with an aeroplane symbol and "Penarth". Thinking that this was a tiny aerodrome meant that I overshot the airport by about 10 miles and was back at Cardiff. WTF is that about?

    1. herman Silver badge

      Re: Cardiff

      Penarth is Welsh for Cardiff International Airport, didn't you know?

      1. Mystic Megabyte Silver badge

        Re: Cardiff

        I bow to your superior knowledge <insert funny emoticon here>.

  11. Andrew Moore Silver badge

    Not new...

    It's not new- I had something like this 15-20 years ago to test GPS signals back when you had to use a special almanac to work out what time of the day you could use your GPS receiver.

  12. Wingtech

    GPS - Not in Rural Areas

    Here in Cornwall it is the non-locals using GPS who end up asking the way.

    Our Postcode is pretty large and has several farms and a Solar Farm in it. The trouble is you can't reach the solar farm from the centre of the PostCode. Since that is mostly trucks, and even articulated lorries, on occasion, it causes much humour seeing them trying to reverse up single-track roads with high banks. I found a driver outside once with his artic. He had clipped a tree down the lane and got it stuck horizontally between cab and trailer. It stuck out 1 metre either side. For much of the last 500 yards he had had 50 cm clearance. What a mess. He was in tears!

    Part of the problem is that even transport firms are not equipping lorries with satnavs which know about such issues. Another is the relatively coarse nature of the Postcode system in the countryside. I wonder which comany might be the first to licence the 3-word navigation system. ( Different codes for front and side gate, for example.

    1. tiggity Silver badge

      Re: GPS - Not in Rural Areas

      You can get specialist HGV specific satnavs / routing systems - not sure how good they are as I do not drive a lorry

  13. Richard Gadsden

    So, can I set up a more powerful version of this and reroute all the traffic down a different street so I can get a quiet night's sleep?

  14. Christian Berger Silver badge

    Well actually that's trivial to detect

    Such a spoofer simulates all satellites with one antenna. So all receiving antennas will get the same signal (but delayed by different amounts).

    So if you use multiple receivers at the corners of your car, you can either compare the time the receivers believe (should be different when spoofed) or you can simply compare the position the receivers report (should be the same when spoofed).

    Of course simple plug in navaids don't have that possibility. For vehicles like planes it should however be utterly trivial to detect spoofing.

  15. Anonymous Coward
    Anonymous Coward

    Trivial = Expensive

    I am sure that threats like this are 'trivial' to defeat - the problem is that you now have 4 sat nav receivers, and they have to be linked (so now we have a new vector for introducing bugs). Meanwhile the 'baddies' will have moved on, found something else - (I suggest a constellation of 4 drones in formation 'simulating' a real sat nav constellation - done right I think that could be made indistinguishable from reality, as they could drift across the sky in appropriate spots on a line of sight between target vehicle and the real satellite. You could have another set of drones spoofing the cell phone towers. Having watched several realistic documentaries about such impossible missions, all that you need is a bright 16 year old hacker, a handful of off the shelf hardware, sticky back plastic and a pizza.

    1. Christian Berger Silver badge

      Re: Trivial = Expensive

      Well the "16 year old hacker" is not the problem here, those understand ethics and therefore won't do any intentional harm.

      BTW using drones for this makes the effort explode. Not only would you need n-times as many transmitters, you'd also need drones which would have to be fairly far away from the receiver, moving at potentially impossible speeds, transmitting at powers which would get noticed.

  16. Richard Pennington 1

    I don't use SatNavs ...

    I am from a generation which learned how to use (and memorise) maps. I do not use (or possess) a SatNav. That said ...

    I live near Farnborough, and it is now Airshow season. The local council has reconfigured the local roads and put up signs "TURN SATNAV OFF", because the roads don't go where (or in the direction) SatNavs think they do.

    In a past life, I was on a project in the Netherlands, and we regularly used to take a taxi from our hotel to the project office. Once the taxi driver took a wrong turn, and his SatNav insisted that he correct the mistake ... by turning right into the local canal.

    For the same employer, but a different location, I had occasion to take a taxi from central Paris to a factory in one of the less salubrious arrondissements. The factory address did not appear on the taxi SatNav, so I had to instruct the driver to go to another address nearby in the same street, and then follow my verbal directions to the factory.

  17. jon honeyball

    GPS transmission kit has been available for not too much money for quite a while

    The LabSat kit from RaceLogic is excellent. I have several of these boxes here at my lab. Battery powered too, so you could drive around with it transmitting that you are in the middle of Milan at 3.25pm last Thursday doing 40kph down a particular street.

    Not that I'd ever do that when stuck in traffic, cos it would be bad and wrong.

    (interesting to note that iPhones and cell-enabled ipads take their date/time from GPS, not from cell network or IP clocks)

  18. Anonymous Coward
    Anonymous Coward

    I don't need a gadget to confuse my GPS..

    .. I have a Mercedes.

    Bought brand new, the map that came with it (which you can only get upgraded if you pay even more money) was of the same age as the rest of the in-car tech: at least 2 years old (I'm being polite here, I was actually surprised the documentation didn't come on parchment).

    In some places it thinks I'n in a meadow, because roads have appeared since. Roundabouts make random occurrences, and its traffic jam detection system is so good that it will give an immediate heads up - if you're in it.

    I also have a phone with the TomTom app, which is marginally better at all of the above. So that's what I ended up using - and I am grateful it's a company car. I now would not buy a Merc at 50% discount unless I had someone I disliked to sell it on to.

    1. batfink

      Re: I don't need a gadget to confuse my GPS..

      It's ok AC - for only several hundred of your English Pounds each time, your local friendly Merc dealer will sell you the annual updates. Bargain!

      Or, as a cheaper option, buy a brand-new TomTom every year and throw away the old ones...

  19. onefang Silver badge

    I'm with the "I don't use GPS" crowd. I'm very good at reading maps and navigating my way around city and bush with just a quick glance at the relevant map.

    I do however regularly turn on the GPS in my smartphone, for when I use Google Daydream, coz Google insists. Daydream wont let you actually use it until you turn on the phones GPS. For those of you not up on the ins and outs of VR headsets, Google Daydream is what is known as a 3DoF headset, with a 3DoF controller (3 Degrees of Freedom). That means it knows about you rotating your head / controller, but has no clue if you move them up / down / left / right / forward / backward. Yet for some add reason, Google Daydream needs to track every single change in position of your head via GPS as you sit on your chair and rotate. Google Daydream actually claims it's using GPS to track the controller, a small BlueTooth thing with a trackpad and a few buttons. Maybe there is a GPS satellite in each end of the controller, and that's what it is tracking? Though you would think that if this is true, it could actually track position as well as rotation of the controller. I smell BS.

    Maybe Google think that when you are in VR, you need to be reminded that you are not actually on the planet Skaro battling hordes of Daleks, you are actually at home in inner city Brisbane, so it can pop up a notification that says "GPS says you are safely at home. Keep calm, and carry on blasting pretend Daleks.", at least until the Cybermen arrive.

    I also sometimes turn on GPS for those tracking style dating apps that tell you "This hottie is 0.4 kms away, perhaps you should run out the door and say G'day to her right now."

    I don't turn on GPS for any other reason. I dread the day the Cybermen use this GPS spoofing, Google Daydream, and a dating app to get me into an awful lot of trouble.

  20. JeffyPoooh Silver badge

    Dead Reckoning

    The better GPS chips, e.g. uBlox NEO line, have wheel pulse input pins so that the car navigation can continue even within tunnels. I have a old Mercedes that successfully noted that I took the left option in a tunnel under a harbour.

    It wouldn't be all that difficult for future chips to alert the user that the GPS signals are seemingly unreliable.

    1. gnasher729 Silver badge

      Re: Dead Reckoning

      Your car should always know its speed, and an iPhone has a built-in compass. Should make it quite hard to misguide you _if these were actually used_.

  21. Anonymous Coward
    Anonymous Coward

    Dear Sirs,

    I am always intrigued by the number of techno-phobes who comment within your forums (normally eschewing such new fangled inventions such as smart phones, sat navs, cruise control etc.). It seems unlikely that they are browsing and responding on a computer. Would I be right that you offer a bespoke internet to parchment transcription service and can you please tell me the correct postal address for my witty interjections, should I commit ink to paper?

    Yours Sincerely,

    A.Fuddy-Dudd Esq.

  22. JohnLH

    What's supposed to be new about this?

  23. Tom -1

    I don't understand why anyone thinks that spoofing is required to get GPS to take you the wrong way. It's famous for it.

    Personally I look at Google Maps if I don't know the route and then while driving watch for signs that indicate problems. Unless I want to wander around pretty much at random and find new places (but still reading signs), which happens from time to time. I haven't yet found myself looking at a cliff or a four fathom deep water passage, but people who trust GPS have told me they hit those problems.


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