> For the complete documentation index, see [llms.txt](https://drotek.gitbook.io/rtk-f9p-positioning-solutions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://drotek.gitbook.io/rtk-f9p-positioning-solutions/tutorials/change-gnss-constellations.md).

# Change GNSS constellations

**This step-by-step tutorial will let you to manually change the GNSS constellations for the Base and the Rover.**

First, connect your GNSS device to a computer using a USB micro cable.

![](/files/-LdEnYZLwhXVFEwUuCNY)

Now start the U**-**blox “u-center” software. Then on the top left corner of the screen, left-click on the reversed tiny black triangle to select the COM Port related to your GNSS device. (it may differs from COM7 as shown in pictures)

![](/files/-LYbIddBqnC-aXKJ1bxh)

Make sure the connection icon is blinking in the bottom state bar. It indicates that the serial communication between the computer and the GNSS device is working.

![](/files/-LYbHSKTiJZ0j0qAf-5e)

Next go to ‘View’ then click on “**Generation 9 Configuration View**”

![](/files/-LYbUsIAWEUg8JmCOVN6)

 A new window showing by default “**GNSS Configuration**” opens.

1. So first, if GNSS configuration is not displayed, then click on “**GNSS Configuration**”.
2. You can now have access to all the GNSS constellations and frequency bands.
3. Tick or Untick the GNSS systems as you wish keeping in mind that Nav Update Rate may be affected by the number of GNSS systems activated.
4. Click consecutively on **RAM**, **BBR** and **Flash** to write changes into RAM and both non-volatile memories (BBR and Flash)
5. Click on ‘**Send Configuration**’

![](/files/-LZ5--juD8GAE3118zYL)

{% hint style="success" %}
You have successfully set the GNSS constellations !
{% endhint %}


---

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