Electromagnetic emitter emitting simultaneously along three orthogonal axes to detect object position and orientation

Abstract

An electromagnetic emission device for helmet position detection systems includes an electromagnetic emitter and control electronics, the emitter comprising three windings arranged perpendicularly, the processing electronics comprising three electronic chains each associated to a given winding and working simultaneously. Each electronic chain comprises closed-loop control means arranged such that the related signal generated comprises three analogue components: a first component, being the stimulus component, modulated at an 'emission' frequency of the winding, each of the three emission frequencies being different from one winding to the next, and a second and a third component, referred to as correction components, modulated at an emission frequency of another winding, the phase and amplitude of which are calculated such as to compensate the parasitic signals received by said winding from the other two windings. Each winding in steady-state only emits electromagnetic radiation at its own emission frequency and at a predetermined phase and intensity.