Configuring the GPS receiver

At this point, the GPS receiver is connected to your PC through the USB port and is ready to configure and verify that all is working OK.

Ublox provides a nice evaluation software package for Windows called u-center that makes this very easy.  You can download it for free from here.  It makes it easy to explore all the configuration options for your receiver and make sure everything is working properly before we move to RTKLIB.

After you have downloaded the program and started it up, use the “Port” option in the “Receiver” tab to select the USB port that the receiver is connected to.  It will probably be the only option, and in my case it is “COM3”.

[Update 11/27/16:  If you don’t see your receivers listed in the Port menu it is probably related to some recent windows driver changes from COM ports to location sensors.  See this post for details]

You should see the connection status box at the bottom of the window go to green and list the baud rate that the receiver is configured for, probably 9600 baud if you haven’t changed it.  If everything is working properly, you should now be able to click on the various display icons and see sky positions, signal strengths, status, etc for all the satellites the receiver is tracking.

To configure the receiver, select the “Configuration View” from the View menu.   All of the receiver configuration options for this receiver will appear in the menu and you can read what the currently is set to with the “Poll” button or change the configuration by changing the settings and hitting “Send”.  For details on what all these settings mean, see the Neo-M8 Receiver Description.

I recommend first increasing the baud rate to something faster than the 9600 default.  I found 115200 worked fine with my setup.  To do this, select “PRT” from the “Configure” window and set the “Baudrate” field to 115200, then  select the “Send” button at the bottom of the page.  You may need to re-select the port to let the eval software match its baudrate to the receiver.





Next, select the “Messages View” from the “View” tab.  From here, you can see which NMEA messages are enabled and being output by the receiver.  The enabled messages are displayed in bold.  You may want to disable all of them to reduce unnecessary information from being continuously transferred over the serial port.  We will be using Ublox specific binary messages for RTKLIB so do not need any of the NMEA messages enabled.  Be aware, though, that the eval software is using these messages, so if you disable them, the display windows will stop updating.  To enable or disable a message, right click on it and select the appropriate action.

Once you have the receiver configured properly, you will want to save the settings to the on-board flash.  Do this from the “CFG” menu item on the “Configuration View” by selecting “Save current configuration” and then the “Send” button.

We still need to enable the raw receiver outputs for pseudorange and carrier phase, but since they require using unsupported commands, we will do that from RTKLIB.

8 thoughts on “Configuring the GPS receiver”

  1. hi I have a question I cant understand this paragraph:”We still need to enable the raw receiver outputs for pseudorange and carrier phase, but since they require using unsupported commands, we will do that from RTKLIB.”
    dont we have access to the raw data for m8t ublox officially?
    I’m new to this and my questions answer may seem obvious but please help me


    1. Hi Hadiseh. This post was from a few years ago and I was referring to the u-blox M8N rather than the u-blox M8T, although that is not obvious when reading this post without first reading the previous one. You are correct that the M8T does officially support raw data and this can be enabled from u-center. By the way, the unsupported debug commands on the newer M8N modules have been encrypted so this post is also out of date in that regard.


  2. Tim, just a heads-up that ublox changed their u-center and now the View > Configurations option is gone. Version 18.08 of u-center only has a View > Generation 9 Configuration menu, which looks significantly different.


    1. Hi Felipe. Yes, I’ve seen this too … I guess I will need to update some of my posts and tutorials. It is still possible to use the old configuration messages from the “Message View” and go to the UBX-CFG message but it’s probably better to get used to the new interface.


  3. I’d like to see if you’d like to be involved with a robotic mowing project. Over a decade ago, I have a scag walk behind doing a good job of mowing with the Satloc rtk single frequency. I was getting cm accuracy and no sync losses.

    Your consulting page has no contact info and neither did Linkin for non premium members.

    I got a system working with the ublox M8T gy-gpsv3 board. I believe I configured it according to your recommendations,not very good results . The boards don’t appear to have the antenna power connected. I am using $25 3Dr radio pair for the baseline coms and they seem to be working well. (1000+ meters)

    The project can be found at

    We are attempting to get several local courses to belly up to the bar to chip in a small amount each month to help fund this.

    Our goal is to perform data fusion with inertial sensors, 3D mapping landmarks, deep learning, k-means edge detection, etc. We believe we can use deep learning to train the mowers with precision RTK and these other sensors, then the trained version should be able to do precise mowing just a single camera and maybe an inertial sensor.

    Please give me a call.

    Peter James
    240 938-8439


    1. Hi Peter. I have not worked with M8T gy-gpsv3 boards but if there is no antenna power I would expect very poor results. I have used M8N GYGPSV5 boards in the past and these did have the power connected and gave quite good results.

      My contact info is on my “About” page but I have just added it to the consulting page as well to avoid confusion. I’d be happy to discuss potential consulting opportunities with you and will give you a call.


  4. OK, now its work. After Load config file in RTKNAVI I need to change the Base station config for “Average for Single Position” and #Ave for 1. Now its work well.


  5. Valente

    Hello, your page is very nice. Congratulations!!
    I’m just start a project a low cost rtk gps. I bougth two u-blox M8T from CGS shop, two Reach Emily and two NavSpark. First I start u-blox M8T and I will try to do with a BeagleBone Black. But for start, I see this post to configuring GPS receiver M8T, but as you recomend, I can’t find “Next, select the “Messages View” from the “View” tab. From here, you can see which NMEA messages are enabled and being output by the receiver.” Could you please help? I try use both in pc with RTKNav but its not work, maybe its a problem in configuration.


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