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Differential GPS? — Parallax Forums

Differential GPS?

Christof Eb.Christof Eb. Posts: 1,161
edited 2024-05-21 15:17 in General Discussion

once again I am in the process of thinking about doing a DIY lawn mower robot. I did think about this several times over the years and meanwhile you can buy them everywhere, so it's a fun and learning project....
My question now is the following:
Is it possible to use 2 lower cost standard GPS- receivers like NEO-6 modules in parallel with a wireless link. One of them at a fixed place, one of them on the robot to calculate the difference of positions? (You can buy RTK systems, but they are much more expensive.
Repeatability of position for this project has to be <5cm, I think.
Thanks, Christof


  • SavageCircuitsSavageCircuits Posts: 235
    edited 2024-05-21 16:26

    My experience with GPS is that the best you can hope for is up to ~2 meters or less of accuracy for a given position. Navigation systems make it look better because they have the "map" data and usually snap to that when the signal drifts off the road.

    Have a look at these options: GPS receiver capable of,, and Galileo (Europe).

  • tritoniumtritonium Posts: 542
    edited 2024-05-21 16:32

    This guy seems to think you can, with an esp32..

    Determine your location to the centimeter around the globe? For everybody, not only for the military? Only with an ESP32 and a decent GPS receiver module? Not possible! Wrong; it is possible by using real-time kinematics. You can even earn money by building a base station and connecting it to a global network (Decentralized physical infrastructure network)!.
    When I got a board from Michael, a viewer of this channel, I was hooked on trying to understand this relatively new technology. Are you interested, too? Then, follow along.


  • As long as I can wear that cool hat and goggles ... smirk

    The 'key' is the "decent GPS receiver module" ... the ESP32 could be a hill of beans for all that would really matter.

  • Thanks for the good inputs! Helps me getting into this.
    For the Ublox brand there seems to be a clear distinction between "standard precision" and "high precision" modules, which can process correction data streams and have the necessary phase detection.
    Neo M8-T seems to be something in between. I have the impression, that it contains the hardware but not the software for RTK but outputs raw data.
    Hm, will have a look onto other navigation methods...

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