> For the complete documentation index, see [llms.txt](https://teravolt.gitbook.io/teravolt/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://teravolt.gitbook.io/teravolt/gps/aeronav-mini/gnss-configuration/how-to-enable-or-disable-gnss-constellations-u-center.md).

# How to Enable or Disable GNSS Constellations (u-center)

**What You Need:**

* u-center 2 software (from [u-blox.com](https://www.u-blox.com/en/product/u-center))
* USB-to-UART adapter connected to the module’s USB-TTL port
* Module powered via 5V

**Step-by-Step Instructions:**

1. Connect the Module
   * Open u-center
   * Go to Receiver → Connection and select your COM port.
   * Wait for the GNSS data stream (NMEA or UBX) to appear.
2. Open GNSS Configuration
   * Go to View → Configuration View (or press F9).
   * In the left pane, select GNSS (CFG-GNSS).
3. Select/Deselect Constellations
   * Tick the checkboxes to enable:
     * GPS
     * Galileo
     * QZSS
     * BeiDou
     * NavIC (IRNSS) → Select L5 only
   * You can disable unused constellations to reduce power consumption or optimize TTFF.
4. Save Your Settings
   * Click the blue Send (→) button at the bottom.
   * Then go to UBX → CFG → CFG in View → Messages View.
   * Choose:
     * Save to BBR (Battery-backed RAM)
     * Save to Flash
   * Click Send again to store the configuration permanently.