Don't Be Ripped Off Buying RTK GPS


If you need precise GNSS for your robots then you need RTK. If you don't know much about RTK, you may lose a lot of money (and hair) on weak RTK GNSS systems. I've written a post to show the beginner what they need for a super solid precision RTK GNSS. Included are specific companies and prices -- I've not seen this guide anywhere else.

Here's hoping it saves you time & money!



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  • In case anybody is interested we just launched the simpleRTK2B, the first low cost evaluation board for the ZED-F9P GNSS module, compatible with Arduino and Pixhawk autopilots.
    If you want to see all the details you can go here:


  • u-blox entering the L1/L2 market (via the F9P) may turn out to be a significant moment in robotics history.

    Unlike some players, u-blox generally under-promises and over-delivers.

  • Hello all!  New guy here.  Have been spending the last few days trying to acquaint myself with the tech options available for the least-expensive GNSS tracking solutions available -- still so much to learn!  Was interested in an older-version C94-M8P that I noticed on eBay, but also the single NEO M8T from 'CSG Shop'.  I have some experience connecting UBLOX GPS modules to SBCs like the Raspberry and Orange Pi computers (including PPS accurate time tracking), and was hoping for something similar for RTK position tracking.  There appear to be RTK base stations in my area (southern Manitoba, Canada), but they are all commercial.  There are public (?) government CACS base stations in my province too, but the nearest is 120km away -- so even 'post-processing' that way seems limited. :(

    In any case, I just noticed this yesterday: it it the 'game changer' that I think it is?

    ZED-F9P module
    u-blox F9 high precision GNSS module
  • Hi! I just signed up as a member on this forum, but I watch carefully, as a guest, for some time. The information you share with us are very interesting and I thank you for it. I  use from two years two 3 Advanced Phantom for surveying and I think it's time to pass on twin motors. I want to use RTK GNSS to remove GCP. We talked to gentlemen from ComNav about the K501G-RTK board. They told me that the board can connect to the hot shoe for the camera, it can connect to a bluetooth modem or 3G modem to retrieve corrections from the national system via the internet.Because I see there are users of this board I would like their confirmation in this type of work, possibly more details (in private) to decide if it is the right choice.Thank you.

  • Hyun,

    Have you inquired to Andy at ComNav directly?

    Keep in mind, if you can't get a good price on the k501g, that you can pick up Unicore's UB352 (GPS/GLONASS L1/L2 20hz) for ~600USD.


    UB352_Boards_Products_High Precision GNSS Board|GNSS Modules|GNSS Receiver
    Unicore Communications, Inc. is a one-stop provider of GNSS products, Unicore's products accuracy ranges from meter, sub-meter, to centimeter and mil…
  • Roby, I inquired four Chinese companies the price of K501G(K100G for some of them). I asked my Chinese friend in China to do that for me. None of them suggested price you noted. not even close. actually double. Price is almost same as Trimble BD970. How could you buy this at 600-900 USD? Is this real market price? I really appreciate if you let me know how to purchase at your price.

    Thanks in advance.

  • Hi Adam,

    Thanks for reading!  Few thoughts:

    Have you contacted Swift and asked for a refund?  I think you may find you'll be $1000 richer without much headache :)

    I was able to do several hours of field testing with the Reach this weekend. It's way better than the Piksi. Hope to test the M8P soon. Anecdotal evidence suggests the M8P should out-perform the M8T with RTKLib (Reach).

    Look forward to hearing your results with the Reach.


  • Hi Roby,

    I really enjoyed reading your blog post!

    Unfortunately, I also purchased the Piksi, and have not had good experiences with it. And now that both the Piksi and SBP protocol have reached their End-of-Life, I don't think there's much hope for the future. I've since opted to keep things simple by purchasing the Emlid Reach for use with PPK processing, and am looking forward to my first field trials.


  • Yes, Pixhawk w/ ArduPilot via

    ArduPlane, ArduCopter, ArduRover source. Contribute to ArduPilot/ardupilot development by creating an account on GitHub.
  • What flight controllers working on k501g? Is Pixhawk1 working on k501g?

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