Sensor system comprising offaxis insensitive multipole magnet

A sensor system comprising:

• a magnetic field generator;
• and
• a sensor device arranged at a distance from said magnetic field generator and adapted for measuring or determining at least one magnetic field component (Bx, By, Bz) and/or at least one magnetic field gradient component (dBx/dx, dBx/dy, dBy/dx, dBy/dy, dBz/dx, dBz/dy);
• said magnetic field generator comprising a multi-pole magnet having a number N of pole pairs that are axially magnetized to generate an N-pole magnetic field that is substantially rotationally symmetric around an axis, said magnet comprising a plurality of grooves and/or elongate protrusions that are arranged in a rotationally symmetric pattern around said axis and that are shaped and sized so as to provide a substantially constant magnetic field gradient in a central region around said axis.