Pypilot yaw reading

[baltika_no_9]

System is Pi4 4GB, 64bit OS, All latest updates to OS and Openplotter, Pypilot 3.2.13. i have a Waveshare 10DOF sensor consisting of an MPU9250 and a BMP280. I've also tried a GY-91 MPU9250/BMP280 with the same results.

I've gone through (fairly quickly!) the calibration routine in Pypilot, IMU only. I see data in Signal K:

navigation.attitude - shows roll, pitch and yaw
navigation.headingMagnetic - shows the heading in Radians

However the figure for heading and the figure for yaw are identical to 15 decimal places. As I move the sensor the heading changes but so does the yaw. I can understand that yaw corresponds to a rotation about the vertical axis and that a change of course is the same but I am trying to understand exactly why those two figures are identical.

I'm sat at home doing this so maybe that isn't realistic.

Can anyone help me understand this?

Thanks

[seandepagnier]

The value is the same, what did you expect?

[baltika_no_9]

Ah OK, I've asked a stupid question, please accept my apologies.

I think I was expecting a value of yaw that represented either the angular displacement from a notional heading, or more properly, the angular rate of change of any rotation about the yaw axis measured in Radians/S. What we have is simply the absolute heading measurement so it puzzled my why we want to report that separately and call it yaw when it is already reported as heading. That did not accord with my understanding of the term yaw but there again I don't really know much, that is clear.

May I ask what are the units for roll, pitch etc that are being reported by Pypilot into Signal K?

Thanks

[ironman]

All units in signalk are SI units; for angles, it's radians. Divide by pi and multiply by 180 to convert to degrees.

[baltika_no_9]

Deleted as there's no need to make another statement of the bleedin' obvious