How Cell Phones Reveal Your Location – Computerphile

How Cell Phones Reveal Your Location – Computerphile

Many of us use Location Services & GPS on smartphones but Cell Phone Companies have been able to track us for a long time. Professor Derek McAuley explains.

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This video was filmed and edited by Sean Riley.

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50 Comments

  1. sparrtak on November 21, 2019 at 7:46 pm

    What about 3g or 4g? Does UDP or TCP pass location data?



  2. Deep Sheep on November 21, 2019 at 7:47 pm

    So, we can expect speeding ticket on our cell phone bills in the near future. Good to know.



  3. fernantyty on November 21, 2019 at 7:48 pm

    If I disable the GPS on my phone, It still can give me an approximation of my location. Is this approximate location based of the technology you show in this video ? 



  4. Sonofawil on November 21, 2019 at 7:50 pm

    Question: If you wanted to create a local network to position your phone/tablet to within a 10 cm and determine its orientation how would you go about it?



  5. wexer82 on November 21, 2019 at 7:51 pm

    first of all, thanks for approving this comment. secondly, great video.



  6. Tte. Damian on November 21, 2019 at 7:54 pm

    I always thought it was a triangulation thing done with various antennas



  7. David Scott on November 21, 2019 at 7:55 pm

    I didn’t realize that the cell tower data could be used to estimate traffic congestion. That’s neat.



  8. frollard on November 21, 2019 at 7:56 pm

    Good video but it doesn’t address how towers use differing signal strength from various different antennae at different sites to triangulate the signal.  We (emergency services) use the azimuth from a tower location when other location services fail to give a line of probability, and if it intersects a major roadway or location of interest we can start there.  



  9. Yuri Aps on November 21, 2019 at 7:59 pm

    Please, put the subtitles!!!!



  10. Yevhenii Diomidov on November 21, 2019 at 8:00 pm

    Ok, the phone needs to know the distance. By why does the tower need to know it?



  11. Sea Wolf on November 21, 2019 at 8:01 pm

    I am sorry i am lazy as truck. So is it right in the movies, they pop the battery out or change the sim, does this stop them from finding you?



  12. Necuno on November 21, 2019 at 8:02 pm

    very cool



  13. tobortine on November 21, 2019 at 8:02 pm

    Professor McAuley should be hailed as a whistle blower for informing us about how the phone suppliers sell our locations to the shop keepers. He’s probably packing for a flight to Moscow right now.



  14. rinu123 on November 21, 2019 at 8:03 pm

    I’ve used a positioning service to locate my phone when I lost it. It was available at my mobile operator’s website. It must have been about 5 years ago.
    The accuracy was terrible.



  15. isgdre on November 21, 2019 at 8:05 pm

    hey, No brown paper.  Good replacement though given the channel.  



  16. kingamongpawns1 on November 21, 2019 at 8:05 pm

    i dont own a smart phone. my phone doesnt have wifi internet or a camera. all it does is text and call. like he said tracking is a given when u have a cell phone. its how they work. my whole life is not  in my phone just a few numbers & i normally only call my wife. that info is worthless…. have at it hoss 



  17. Jason B on November 21, 2019 at 8:07 pm

    We should know that they could track us through your phone. There are many free aps and games in which you must agree to allow location services. By loading these freebies, we give permission for them to track us.



  18. papst97 on November 21, 2019 at 8:09 pm

    What about triangular tracking with 2 or more towers???



  19. ZER0 on November 21, 2019 at 8:09 pm

    There have been many times when Ive woken up after a heavy night and would love my mobile to tell me where I was.



  20. kasuha on November 21, 2019 at 8:10 pm

    It’s not all. If you’re talking or transferring data, not only your current station knows in which sector and how far you are, it even knows how strong signal your phone has to other nearby stations. The phone measures it and reports it to the station so it can decide when you should switch to another station. That also allows to pinpoint your position rather precisely. When the phone is just switched on, though, it talks to the station very rarely and does not send those measurements. Then the station just knows you’re somewhere within its area and does not even know the distance since you may have moved significantly since last time it talked with your phone.



  21. skyler Amato on November 21, 2019 at 8:10 pm

    what about texts, is it transmitted the same way?



  22. Larry Bolan on November 21, 2019 at 8:10 pm

    One of my EET professors actually does cell phone forensics in court cases… this is pretty powerful (albeit usually circumstantial) evidence when properly presented.



  23. Anders Öhlund on November 21, 2019 at 8:11 pm

    At 4:15 This speed limit is also the main reason cellphones had to be turned off on airplanes. Not because of air safety but because it confuses the GSM network. Also way up in the air it is hard to determine what cell tower below is closest to your phone which further confuses the system.



  24. MADagain on November 21, 2019 at 8:13 pm

    If the phone companies are monitoring me and knowing that its me… i think this is a hugeee invasion of privacy… good thing i never use my phone and its always at home 🙂



  25. tokfrans on November 21, 2019 at 8:14 pm

    I don’t care at all if I’m being watched. I haven’t done shit so why even bother caring lol



  26. salat on November 21, 2019 at 8:14 pm

    No word about handover/cell roaming ?



  27. SkiBaBopDiBop on November 21, 2019 at 8:15 pm

    But if your phone’s off than they can’t do anything.



  28. T Orrent on November 21, 2019 at 8:15 pm

    "Big brother" was never the danger. The danger is the big bully trying to steal your lunch money. Corporations want to know everything about you so they can nickel and dime every nickel and dime out of your pockets. The 1%ers want to know everything about you so they can own everything.



  29. EcceJack on November 21, 2019 at 8:15 pm

    I recall that at least two of my old mobile phones (cell phones, or however you decide to call them) had shown, on the main screen, just under the network name, or clock, or something, a rough location. And I found it quite interesting. That was back in Slovenia, and I’m not sure how the privacy things are sorted out there, but even here in the UK the phone was at least able to give me the area code (say 01223 when I was in Cambridge) – you as the end user still need a map of area codes to work out your location from that (and the accuracy is much lower than for the other system), but it does seem that it’s possible – at least in principle – to have some of this location info available for the end user.

    ……Mind you, my shiny new smartphone isn’t as smart as that and can’t figure out its location without GPS or at least WiFi.



  30. Be Cu on November 21, 2019 at 8:16 pm

    GOOD



  31. itsThe1300 on November 21, 2019 at 8:16 pm

    Very interesting video! I had never really thought about the base stations splitting their reception into time windows for each phone but it makes perfect sense. Very informative! Keep it up!



  32. MrTheAer on November 21, 2019 at 8:19 pm

    Ey, what about triangulation?!



  33. Dhaval Srivastava on November 21, 2019 at 8:20 pm

    So this is how Google locates us without GPS? Also gives us traffic information (where it’s slow or normal) ?



  34. Cuca Belludo on November 21, 2019 at 8:23 pm

    If take the battery off they still can track??



  35. The other John Smith on November 21, 2019 at 8:26 pm

    The problem is that phone companies *can’t not* know where you are, becasue it’s instrinsic to the system. This must include 3G and 4G connection as well.

    If I’m not mistaken, 3G and 4G cell antennas have a shorter range, because of the frequency being higher. Shorter range means it’s possible to serve more phones at once, but it also means those phones can be geographically located to a finer degree…

    Scary. Because I have no way of knowing what my phone company does with my location. And turning it off is impossible. And there’s no opt-out – there couldn’t be.



  36. Ian Rose on November 21, 2019 at 8:27 pm

    Nice voice!



  37. RogerWilco on November 21, 2019 at 8:29 pm

    This is how the original iPhone figured out your location, before they built in GPS with the iPhone 3G. It was pretty accurate given the limitations of the technology.



  38. TechyBen on November 21, 2019 at 8:30 pm

    I actually had a friend complain about his hands free cutting out while driving. Then I reminded him he was talking on a wireless device, with someone 100 miles away, while driving at 70mph past multiple towers and everyone else possibly doing the same. It was amazing that he could do all this in the first place. 🙂



  39. Vladimir Georgiev on November 21, 2019 at 8:31 pm

    What about your location in case of NO GPS and airplane mode.
    Just go home and turn on the WiFi only. Then start Google Maps. You will wonder that Google know your exactly location. Please, note that you can not find your location based on your IP address using any web page…
    Then how Google know where you are ?



  40. Oussama Kassah on November 21, 2019 at 8:33 pm

    I think you can also triangulate the position by using 3 towers and their relative distances to the mobile phone.



  41. ZipplyZane on November 21, 2019 at 8:34 pm

    So nothing about triangulation, using two or more cell towers to narrow down your location even more?



  42. GaryKildall on November 21, 2019 at 8:34 pm

    We live in a Big Brother world. And we enjoy it until it is too late. There is no return. It is just a matter of fact and time before we are judged without law.



  43. Karmic Beats on November 21, 2019 at 8:34 pm

    The accuracy of location data from cell phone towers is increasingly coming under fire. It turns out that they cannot give a very accurate information. This is becoming an issue in legal cases where that info is used to try and say where someone was a certain time. In one case someone was convicted of murder. On appeal they proved their innocence as a call just minutes prior to the incriminating call, showed them 20 miles away. That is one call showed them in the area of the murder, while a call a few minutes earlier showed them 20 miles away.

    Cellphone tower data is completely unreliable for pinpointing persons location even to a large general area.



  44. Pontus Welin on November 21, 2019 at 8:36 pm

    What about triangulation? If you are close enough to two or more towers, can’t they get a very exact position?



  45. thejumperkin on November 21, 2019 at 8:37 pm

    Beautiful explanation of something I was very interested in.. At least the mobile phone communication part (hadn’t considered that many factors on mobile communication at all..). Such an informative video
    Wondering why Youtube took so long to suggest it to me lol

    Thanks <3



  46. NumptyGrumble on November 21, 2019 at 8:39 pm

    With the ethernet systems the length of cable was limited (eg 200m for 10Base2) and terminated with a set impedence to prevent reflections which is why collision detection was practical. With radio waves its not possible to do this and signal strength will vary depending on local conditions like surrounding hills/buildings and the weather (eg raining). Satellite systems have the same problem. Think there were plans to produce a mobile network based on Satellite network in the 90s. Kind of interesting to speculate how the owners of of the satellite network would do with location data at a global rather than national level.



  47. Stephen Mortimer on November 21, 2019 at 8:41 pm

    I am shamed! A guy somewhat my age has a grasp on all of this! Brady this is somewhat damaging for my ego!!



  48. Zach Hale on November 21, 2019 at 8:41 pm

    I think this is one of the most nerdy, information packed YouTube channels I’ve ever come across. I love it!!!



  49. shortstack on November 21, 2019 at 8:43 pm

    This is why I walk around with a tinfoil hat 0_o lol



  50. veran on November 21, 2019 at 8:44 pm

    Would be interesting to see how the Computerphile professors react to Watch_Dogs similar to how the SixtySymbols professors reacted to Portal…