Patent ID: 8494793

Claim:
A process that measures a gradient (n=1), or an n-th order derivative with n greater than 1, in a direction z or x, of a component Hx of a magnetic field, the component being invariant, at least locally, in a direction y (x, y, and z being perpendicular two by two), the process comprising: a) positioning of N (N≧n+1) elementary field sensors in a zone in which the magnetic field component is invariant in a direction y, and each sensor being offset, in relation to the preceding and/or following sensor: along y, by a distance T y , along the z axis by a distance Δz, or along the x axis by a distance Δx; b) measuring the field by each of the N sensors; and c) calculating, by a computer, a processor, or an integrated circuit, a value of a gradient, or the n-th order derivative, as a function of the measurement values of the field obtained during the measurement, and using, by the computer, the processor, or the integrated circuit, the value of the gradient or the n-th order derivative to determine an electrical current flowing in a conductor external to the N sensors.