A METHOD OF CALIBRATING AN INERTIAL MEASUREMENT UNIT

A method of calibrating an inertial measurement unit comprising a plurality of accelerometers, a plurality of gyroscopes, and a plurality of magnetometers, the method comprising: collecting data from the inertial measurement unit, while stationary as a first step, in a local environment where the inertial measurement unit is anticipated to be used post calibration; collecting data from the inertial measurement unit while repositioning the inertial measurement unit around three orthogonal axes of the inertial measurement unit as a second step in the local environment; calibrating the plurality of gyroscopes using the data collected during the first step and the second step; calibrating the plurality of magnetometers using the data collected during the first step and the second step; calibrating the plurality of accelerometers using the data collected during the first step and the second step; where calibrating the plurality of magnetometers includes forming a cost function using deviations in data, from the plurality of magnetometers, from an assumption that at least one of an angle and a length of each of the plurality of magnetometers are identical; and, where calibrating the plurality of magnetometers includes establishing a threshold for the cost function beyond which an unaccounted for magnetic distortion exists.