ADIS16497 gyro bias instability after power-on


We use ADIS16497-1 IMU in inertia navigation project.

But I can observe the following....

After power-on from a cold condition (internal temp about 22 C) all gyro outputs exponently changes from its initial values (about -0,13 deg/s for X, 0,18 deg/s for Y, -0,05 deg/s for Z) to target stable values (about 0,02 deg/s). This process take a time within a 15 mins. Internal temp of IMU changes for 4 degs. All accelerometers works perfectly.

After hardware reset of IMU all gyro outputs saves a stable values.

After power restart (10 sec pause) gyro outputs changes from a 0,01 to stable values.

After warm start (15 min pause in off condition) gyro outputs runs from a 0,1 - 0,15 deg/s to stable values. Internal temp changes from 28 to 33 deg C.

It's worth noting that axis Z has a better temp stability and has a minimal power-up changes.

Transient power voltage of IMU was within 20 mV. Temperature instabilities (for stable condition of gyro bias) was measured in temperature band from 15 to 65 C and not exceed values of 0,02 deg/s.

In datasheet rev.D for ADIS16497 Power-On Start-Up Time is a 265 ms and not include some aspects, which can affect overall accuracy.

Please say something more about start-up process in gyro. How long time needs for initial gyro stabilization process? What is the cause of the instability of the initial zero offset of gyro at power-up time?

Best regards,