Big drift in openIMU300ZI yaw angle

Hi, recently i bought an openIMU300ZI IMU for outdoor ugv nagivation. I have a problem with the heading.

I am currently I using the VG_AHRS application, but the problem is, even when the robot is not moving, the value either keeps increasing or decreasing. For example, let's say that the current heading is 30 degrees even without moving the robot, overtime the value keep increase or decrease until it have a significant dift it would became 60 or 70. and even when moving the robot. the dift keep happening.

This is my first time to use openimu products, I am seeking your assistance.

Hi @Abdelrahman,

1. Please use AHRS application in low distortion magnetic environment, as mag sensor is very sensitive to magnetic interference.
2. Please apply magnetic alignment (as below screenshot) in no magnetic distortion environment at first and check if initial heading is correct.
   
3. If it takes long time to convergent correct heading in static condition, as AHRS is an open-source app, customers could try to adjust “gKalmanFilter.R[STATE_YAW]” (as below screenshot) to lower values, like 1.0e-3, 1.0e-4, 1.0e-5 … in their customized applications.
   
4. Could you help to collect some field test data? This might require using a custom FW to collect all the information required for the algorithm to do post analysis. Test data should include accel, raw gyro, raw mag, corrected mag data, roll, pitch and heading data at 100Hz message rate from power on, as well as hard and soft iron parameters shown in above screenshot.

Thank you for your reply. I will try to modify this part of the code and update u.