Calibration of start orientations of the inertial motion capture system devices

We present a way to calibrate start orientations of inertial measurements units of the motion capture systems. In this article we described two inertial motion capture systems and reasons of need of a calibration process of start orientations of their devices. Algorithms of the calibration for devices of one inertial motion capture system: three algorithms without using of additional data and two - with - are described. For each described algorithm and for each calibration pose advantages and disadvantages are described.