UAS/Notes/IMU

Inertial Measurement Unit (IMU)

The IMU was are going to create will consist of an 3 axis acceleration, a 3axis gyroscope, a 3 axis magnetometer, and a barometer. These combined will give us 10 degrees of freedom.

6 dof algorithm
Here is what our algorithm will do:
- accelerometer tells us: "You are now at position Racc"
- we say "Thank you, but let me check",
- then correct this information with gyroscope data as well as with past Rest data and we output a new estimated vector Rest.
- we consider Rest to be our "best bet" as to the current position of the device.

some algorithum i found

• Read the 3 axis magnetometer data

• Calculate the "tilt compensated" x and y magnetic component (standard formulation):
  • CMx = mag_x*cos(pitch) + mag_y*sin(roll)sin(pitch) + mag_z*cos(roll)sin(pitch) CMy = mag_y*cos(roll) - mag_z*sin(roll)

• Calculate the magnetic heading with this compensated components:
  • MAG_Heading = Atan(CMy/CMx)

http://code.google.com/p/sf9domahrs/ might have the code we are looking for.