Patent ID: 8433545
Filing Date: 2013-04-30
Classification: G05F

Abstract:
1. A system for compensating electromagnetic interfering fields of objects to be protected, comprising: two triaxial magnetic field sensors configured to output real sensor signals (S); six compensation coils arranged as a cage around the object to be protected and actuated individually; and a control unit with control loops, the control unit having a digital processor, six inputs, and six outputs, the digital processor receives the real sensor signals (S) at the six inputs and processes the real sensor signals into real control signals (O) for the six compensation coils, wherein the real sensor signals (S) are converted to virtual sensor signals (V) by a first matrix multiplication to map interfering fields at a location of the object, whereupon the virtual sensor signals are made to modified signals ({circumflex over (V)}) by the control loops, wherein the transition from the virtual sensor signals (V) to the modified signals ({circumflex over (V)}) is described by multiplication of the virtual sensor signals (V) with a matrix (Ω) such that {circumflex over (V)}=Ω·V, wherein the modified signals ({circumflex over (V)}) are converted to the real control signals (O) by a second matrix multiplication, the real control signals (O) being individually fed to the six compensation coils at the six outputs.