Problem with gnss fusion calibration not ending

[whypushhh]

I asked a question last time, but didn’t get an answer, so I’m posting it as the main question again.

• Host configuration:
  • ROS 2 Foxy
  • zed-ros2-wrapper -b humble-4.1.4
  • ZED SDK 4.1.4

2. GPS Topic: When I check the /fix topic using ros2 topic echo, the covariance data appears to be normal, as shown below:

3. GNSS Fusion: I perform GNSS fusion by running the following command:
   ros2 launch zed_wrapper zed_camera.launch.py camera_model:=zedx enable_gnss:=true

• I modified config/common.yaml to set gnss_enable: true, but this did not take effect, so I forcibly set it via the terminal.

4. Results:

• The /zed/zed_node/pose/origin_fix topic shows the following:

• The /zed/zed_node/pose/fused_fix topic shows the following:

Although the latitude, longitude, and altitude appear to be correct, the covariance in /origin_fix is filled with -1.
5. Code Review: I reviewed the zed_camera_component.cpp code at line 8170:

• It seems that if the covariance type is COVARIANCE_TYPE_UNKNOWN, it is filled with -1. However, in my case, the type is 2, which is not unknown.

6. Logs and Timestamp Issue: I am also seeing logs indicating “covariance is small, and the timestamp is mismatched.” These logs repeat very quickly:

Calibration in progress continues without end

Questions:

1. Why is the covariance in /origin_fix filled with -1 when the covariance type is 2 (not COVARIANCE_TYPE_UNKNOWN)?
2. Could there be a configuration or process I missed in enabling proper GNSS fusion?
3. Regarding the timestamp issue:

• What might cause the timestamp mismatch?
• Is there a recommended approach to synchronize timestamps for ZED and GNSS fusion?

4. Is the continuation of calibration a timestamp issue or an inability to subscribe to the covariance value? There is no problem with the GPS values ​​I publish.

I would greatly appreciate your advice and suggestions to resolve these issues. Thank you!