MPU-9150 DMP: Disabling Gyro Calibration Ignores Existing

Hi there,

I am using the MPU-9150 DMP with MotionDriver 5.1.2 to get 6-axis Quaternions. I have noticed that if I disable the Automatic Gyro Calibration feature (DMP_FEATURE_GYRO_CAL), the DMP then ignores any biases already pushed down to the DMP memory - reverting to '0' calibration. This effectively renders the DMP Quaternions useless due to drift from the Gyro Bias.

The reason this is a problem for us is that we want to use the MPU-9150 as part of our marine propulsion control system - and if we enable the Calibration then a boat drifting in a fixed current will get that movement calibrated out after 8 seconds. This is very undesirable. Basically we want to calibrate ONCE and then use those biases from that point on - but the software is forcing us to either calibrate continuously, or not at all.

Is there a way to get the DMP to use the Gyro Biases that have been pushed down to it BUT NOT re-calculate them after 8 seconds of what it thinks is "no movement"?

Alternatively could anyone provide a bit more information about what is classed as "no movement"? Will a boat undergoing a fixed rate of rotation due to a steady current qualify as "no movement" and so get erroneously calibrated? Or not?

I can't believe I'm the first to notice this. My problem is similar to that described here - viewtopic.php?f=3&t=393.
This did not appear to get resolved.

Unfortunately we are on the other side of the world and could not make it to the Developers Conference to ask anyone in person. Any help will be greatly appreciated.

Cheers and Have a Good Day