GPS Without GPS

Open Electronics just released a neat little board that can place you on a map without using GPS.

The board works on the basic principles of a cellphone network – the ‘cell’ network is a series of towers that are placed more or less equidistant to each other. Save for the most desolate parts of the country, a cell tower usually communicates with a phone one or two miles away. Usually, several cell towers can be seen, so the position of a cellphone can be pinpointed to within 200-350 feet. Translating cell towers to latitude and longitude is easily done by querying a Google database that was created for the mobile version of Google Maps.

The board itself is a PIC18 microcontroller and a SIM900 GSM module. The firmware available at Open Electronics is pretty impressive – all communication to the board is handled through SMS and the phone can report it’s location to 8 other phones.

It’s pretty impressive to think the same technology that caught [Kevin Mitnick] is now available to the masses. We’re wondering what Hack a Day readers would use this for, so if you have an idea leave a comment.

32 thoughts on “GPS Without GPS

  1. Vodafone has something similar in Romania. They use the “cell broadcast” (“cell broad”, “broadcast”, “cell info”, cell info display”) function of the phone.
    You get the name of the town you are in, or the name of a street if you are in a big city.
    It’s not very exact, but sometimes it’s useful :)

  2. Not nearly precise enough for most applications I would think. I wonder if you absolutely need an active account or if the modules can pick up on what towers are in the area without an active sim. Obviously you’d have to have a local copy of the cell tower database. I imagine something similar could be done with a wifi finder and a local copy of a wifi database.

  3. Not precise enough? I disagree. This is great for tracking, anti-theft, and lower power applications. Low power especially, as instead of waiting for the gps lock and keeping that running, you can wake up, snap a shot of the surrounding towers, and power down.

    This is great for applications that require infrequent updating or ones that only need to have the location data downloaded after the fact. Also, applications that may not have even a practical line of sight to the sky, maybe.

  4. So it’s less accurate than GPS, costs to send SMS and for data rates to access the google database… How is this ever going to be a beter solution than a GPS module? They only cost $10-$15 these days and are far more accurate, smaller and quite frankly, mose useful…
    Am i just missing something here? I don’t like to complain about other peoples projects, but i would honestly like to know what the season for this project is/was/will be becasue i can’t see any use for it at all

  5. You guys have no imagination. It would be useful at least for a ballpark ‘where am I?’ in the case GPS goes down or is experiencing interference. On a navigation device it would at least show the map segment you are in and hopefully you’re not too stupid to navigate given a small map section.

    I imagine it wouldn’t work very well higher up in altitude, like in a plane where you are going to receive more signals from more cell towers than on the ground.

  6. Now if they just start installing those cheap atomic clocks they are now making in the cell towers we could have a much more accurate cell based positioning system that would even work in buildings well. The only problem is the cost of the clocks and that it might be too accurate.

  7. You would need an activated sim card for this to work, right? I mean, you need to have a payment plan with some service that permits the device to receive and send texts, and access the internet to query google maps for coordinates, right? And you’d receive the coordinates on another phone. So, you need at minimum, two contracts with cellular phone services, like Verizon or what not, right? I’m just wondering if this would be cheaper than one of those Insignia Little Buddy things.

    Would there be a way to receive the coordinates, instead of on a cell phone, on a computer? You know, so I don’t have to hold up my phone, and copy the long coordinates into Google Maps for every single text message?

  8. Sorry, but as far as I know, Mitnick was using an AMPS phone when was caught… And the device that tracked him was similiar to a bird tracking device (setorial antennas and pwr meters).

  9. Interesting project and supprising to see that the cost of GSM modules make it possible.

    For a ‘low jack’ implementation could you just SMS the tower data back home and then look it up independantly – this wouldn’t require the module to have a GPRS account…

  10. Hey Ned,
    GPS modules for $10 -$15? Where? I agree I do not like the payment for the service, but I do find it really useful. How? well not exactly the way it is described but
    a) It can be used as logger for free (cell info can be read from the phone). No need to pay for SMS or GPRS. Store cell info in storage on the micro and retrieve it later.
    b) Simple tracker. Keep a small database of cell id’s in the micro. Just the local database every-day kind of a thing. Report (via SMS to an external phone) any time the phone goes to an
    unknown cell ID.
    c) On demand. Wait for a SMS from a number to trigger the retrieval of info via SMS from the device (retrieve current, past locations or both).

    In all cases there is a need to look it up from another device (receiver) that it is assumed to have internet connection.

  11. In the CCC 27 (27c3) GSM cracking demonstration they had software to track this also. It was fairly accurate. It couldn’t get GPS precision but it wasn’t off by more than 100ft or so.

  12. @Carlos;
    Here is a link for a GPS module for $14.30 including shipping
    I know they are a shit module, but will get better positioning data compared to cell tower triangulation.
    I see that it is kinda usefull, but for a few extra $$ you could have used a GSM module with a GPS receiver built in or added a stand alone GPS module and this project would have been infinitely better.
    I would just hate to have to pay for data to figure out where i am.
    Also; i’m assuming using it as a logger like you used as an example will require a lot more memory in raw data compared to a 8 bytes for a GPS location..

    I also read that you say GSM is smaller and less bulky? How do you figure? I’m using the Venus chip in my projects and granted it costs $25 in single quantity so it costs a bit more but it is only 10mm2 in size so even smaller than your PIC right?

    I like the project, i really do, i just fail to see where it would be useful…

  13. This is akin to LORAN. Three radio towers with three freqs. As long as you have three towers to get a fix the system should be fine. But, like LORAN if you get into hilly country or coverage is sparse your accuracy will go away.

  14. has anybody considered a project using both GPS and GSM in one tracking device? say if the GPS can’t get a lock in XX minutes then text back home the GSM’s best guess. since the GSM would not be as accurate you could even have the GPS try again in a short period of time. therefore your odds of getting an accurate hit quickly after the target leaves the zone of interference are much higher, and that would let you refine your estimation as to their location

  15. This is a nice and compact tool which can be used to keep track of elderly people, childeren, and pets if the risk of getting lost is present!

    Just built it into some sort of bracelet, and you can build a tracing system.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.