youtube name: MicWro Engr

Note that these videos contain theory learned from Michael's reading.
He does not have any demonstrable hardware or software.

\https://youtu.be/LjeFZetmfYc?si=fNag0weh7Y1BTe6-

Inertial Reference Frame
Earth-Centered Inertial Frame, ECI Frame

IMU = accelerometer + gyroscope + (optional) magnetometer

measures angular rotation rate in radians per second or degrees per second
has bias and drift

bias
when the sensor is stationary, the measurement is non-zero.
this means that the measurements are off-center.

drift
when we calculate the angles of the current orientation, by looking at the measurements over time, the bias in those measurements leads to drift in the current position angles.

summary: gyro bias causes gyro drift

how to eliminate bias and drift: Extended Kalman Filter

measures linear acceleration in 3 axes: x,y,z

four accelerations: linear, gravity, coriolis, centripetal

measured acceleration = linear and gravity - coriolis + centripetal

coriolis and centripetal acceleration depend on earth's rotation, velocity, and position
These are fine measurements relevant only to high-precision sensors.

by looking at acceleration due to gravity, we can estimate roll and pitch
roll, phi, φ
pitch, theta, θ

integrate acceleration to velocity
integrate velocity to position

accelerometer also has bias which leads to drift in velocity and position
Extended Kalman Filter can be used to eliminate bias

accelerometer also has noise, due to vibration
Low-pass filter can be used to eliminate noise.

Note: do NOT use a low-pass filter on gyroscope readings

IMU grade and accuracy