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Configuring the Baud Rate of a u-blox GPS Module

Configuring the Baud Rate of a u-blox GPS Module

Background and Purpose

When a u-blox GPS module is moved between flight-controller firmware platforms, a baud-rate mismatch can prevent detection. For example, ArduPilot may change a GPS module to a different baud rate, such as 230400, while the target firmware or configuration may expect 115200. A GPS module previously used with ArduPilot may therefore be unavailable in Betaflight.

This guide explains how to use the official u-blox u-center application to set the GPS module to 115200 baud and make the setting persistent for compatibility with Betaflight and other firmware.

Requirements

Software

U-Center

Download and install u-center. This guide uses version 24.05.

Drivers

Install the driver required by the USB-to-UART adapter:

Hardware

  • A u-blox GPS module, such as MicoAir MG-A01, M10G-5883, or MG-902
  • A USB-to-UART serial adapter
  • Connection wires: 2.54 mm Dupont wires or SH1.0 terminal wires

Hardware Connection

When connecting the GPS module through a USB-to-UART adapter, cross the serial data lines:

USB-to-UART adapterGPS moduleDescription
5V5VPower
GNDGNDGround
TXDRXAdapter transmit to GPS receive
RXDTXAdapter receive to GPS transmit

Wiring diagram:

After connecting the adapter to the computer, open Windows Device Manager → Ports (COM & LPT). Confirm that the device is detected and note its COM port, such as COM59 in the following example.

Configuration Procedure

Step 1: Establish Communication

  1. Open u-center.
  2. Select Receiver → Autobauding to enable automatic baud-rate detection.
  3. Select Receiver → Connection, then choose the correct COM port.
  4. When the connection succeeds, the status-bar indicator turns green and flashes, and u-center displays the detected baud rate. The example shows 9600 baud.

Step 2: Read the Current Configuration

  1. Select View → Configuration View or press Ctrl+F9.
  2. Select PRT (Ports) in the left pane.
  3. Read and record the GPS module's current value in Baudrate, such as 38400 in the example.

Step 3: Synchronize the U-Center Baud Rate

Manually lock u-center to the detected baud rate before changing the configuration:

  1. Select Receiver → Autobauding to disable automatic detection.
  2. In the baud-rate selector on the toolbar, choose the value read in Step 2, such as 38400.
  3. Press F6 to open Packet Console. A continuously updating data stream confirms that communication is working.

Step 4: Change and Apply the Baud Rate

  1. Return to Configuration View → PRT (Ports).
  2. Set Baudrate to the target value, 115200.
  3. Click Send in the lower-left corner.
  • Note: Communication stops at this point because the GPS module has switched to the new baud rate while u-center is still using the old rate.

Step 5: Save the Configuration — Required

The new baud rate must be written to nonvolatile memory (Flash/EEPROM); otherwise, it is lost when the GPS module is powered off.

  1. In the u-center toolbar, manually change the baud rate to 115200 to restore communication.
  2. In Configuration View, select CFG (Configuration) in the left pane.
  3. Save the configuration:
    • Select Save current configuration.
    • In the Devices list, select every entry from 0 through 4; selected entries turn blue.
    • Click Send in the lower-left corner.

Final Verification

Power-cycle the module to check that the new baud rate was saved. This is a configuration-persistence check, not a GNSS cold-start test:

  1. Close u-center, disconnect the USB adapter, and completely remove power.
  2. Reconnect the USB adapter to the computer.
  3. Open u-center and set its baud rate directly to 115200.
  4. Connect to the COM port and open Packet Console with F6.
  5. If the data stream updates continuously, the 115200 baud setting has been applied and saved successfully.