Patent ID: 7855555

Claim:
A method of measuring the value of an external magnetic field by using a magnetoresistive sensor, the method being characterized in that it comprises: a first step consisting in applying, in situ, prior to each measurement of the external magnetic field, at least one additional magnetic field pulse in the space containing the magnetoresistive sensor, said first step itself comprising a first substep consisting in applying a first additional magnetic field pulse presenting a first value of positive polarity and of magnitude sufficient for saturating the sensor, and in measuring the maximum value at high saturation (R max ) of the resistance of the sensor, and a second substep consisting in applying a second additional magnetic field pulse presenting a second value having negative polarity and magnitude sufficient for saturating the sensor, and in measuring the minimum value at low saturation (R min ) of the resistance of the sensor; and a second step during which a predetermined value of said additional magnetic field is applied that does not saturate the sensor, and in which the effective resistance (R eff ) of the magnetoresistive sensor is measured and the measurement of the effective resistance (R eff ) is automatically calibrated using the maximum and minimum values at high and low saturation (R max , R min ) as previously measured in order to determine a corrected resistance value (R cor ) from which the value of the external magnetic field is determined.