Sensor x y z coordinate frames

[adam-at-epsilon]

Determine how x, y and z axes are oriented for gyroscope, magnetometer and accelerometer, whether they are in agreement or need rotation before use.

[adam-at-epsilon]

The coordinate frame of our quadcopter fuselage is:

Positive x points forward between M1 and M2 arms. Positive y becomes starboard. Positive z is down.

See Flight Dynamics

[adam-at-epsilon]

Gyro & accelerometer analysed (they have their axes according to their respective datasheets, but not aligned)

In progress.

[adam-at-epsilon]

[adam-at-epsilon]

The inclination of earth's magnetic field in Malmo is high, about 70 degrees. The declination (horizontal offset) seems to be near zero (see isoclinic map links in link below).

The magnetometer shows positive values for magnetic north (cross-checked with actual compass).

This link has further links to maps showing inclination and declination of earth's magnetic field. http://gravmag.ou.edu/mag_earth/mag_earth.html

[adam-at-epsilon]

This is hopefully clear how the sensors are orientated with respect to the quadcopter body frame.

@DanielStenis Is the STM32F3 orientation correctly depicted (i.e. the "diode circle" points ahead?)

[adam-at-epsilon]

done with commit referenced just above. Diagram of coordinate frames added to wiki page "Sensors"

[stenbergd]

Looks right!

Maybe we could make an enum struct that makes it possible for us to redefine the coordinate system relative to the board?