How to Optimize the F9P's Navigation & Measurement Rate (Frequency) – u-blox Services

When increasing the CFG-RATE-MEAS and CFG-RATE-NAV settings, it’s crucial to adjust other configurations to ensure optimal performance. Improper setup can lead to buffer or memory errors, impacting performance and use of PointPerfect corrections. Use the UBX-MON-COMMS message to verify that the module is free from such errors after updating these settings.

Before You Start

Review the F9P Data Sheet: Consult the relevant section, “1 Functional Description,” to understand the module’s performance limitations. Link to F9P Documentation & Resources
Familiarize Yourself with Configuration Tools: Refer to the Documentation & Resources and the u-center Guide for configuration instructions.

Step-by-Step Optimization

1. Maximize the Baud Rate

Set the baud rate to 921,600 or the highest value your hardware supports.
Higher baud rates ensure sufficient data throughput, especially when operating at high navigation rates.

2. Configure GNSS Constellations

Enable Only Necessary Constellations:
- For PointPerfect, ensure the GNSS signals specified under the PointPerfect specification are enabled.
- Disable non-major constellations like SBAS, QZSS, IMES, and NAVIC.
For Higher Rates Limit Constellations:
- To achieve rates above 10 Hz, reduce the number of enabled constellations to fewer than four.
- Note: Disabling constellations used by PointPerfect may decrease accuracy and prevent achieving a PPP-RTK Fixed solution.

3. Disable Unnecessary CFG-MSGOUT Messages

Minimize Message Outputs:
- Disable all unused message outputs, even if their corresponding protocol (e.g., I2C, SPI, UART1, UART2, USB) is not in use.
Example Configuration:
- If you only need GGA messages over USB, disable all other messages and outputs for protocols like UART or SPI.

4. Verify and Monitor Performance

After increasing the navigation rate, use UBX-MON-COMMS to check for:
- Buffer overflows (txBufFullError: yes)
- Insufficient memory (memAllocError: yes)
- Ports with 100% usage
Adjust configurations and retest if any errors are detected.

By following these steps, you can maximize the F9P’s navigation and measurement rates while maintaining stability and performance.

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