Inquiry Regarding Altitude Issue on L96 M33 Module

IoT Modules GNSS Module
1

Dear L96 Support Team,

We are preparing to use the L96 M33 module and have designed our PCB according to the guidelines provided in the Quectel documentation. GNSS fix times are excellent, and the DOP values are also very good. However, we are consistently seeing an incorrect altitude value reported in the NMEA GGA sentence: it always shows a negative value (around -180 m), even though our city is located at approximately 1500 m AMSL.

We have tested GPS and GLONASS (both together and separately), but the result remains the same.

Do you have any suggestions on what might be causing this issue?

Thank you in advance for your support.

3

Dear Meysam,

Thank you for reaching out. To assist you further, could you please provide the following details:

  1. Firmware Version of L96
    You can retrieve this by sending the command:
$PQVERNO,R*3F

  1. NMEA Log Showing the period where Incorrect Altitude Issue occur
    The log file can be found in the logFile directory.

  2. Hardware and Software Details

  • Are you using your own design or an Evaluation Board (EVB)?
  • Which version of QGNSS are you currently using?

Once we have this information, we’ll be able to analyze the issue and provide accurate guidance.

Best regards