A method for locating an object relative to an array of magnetic sensors in an environment in which there is present a noise signal having a fundamental frequency f_NOISE, includes generating one or more magnetic signals by means of one or more magnetic emitters mounted at known locations on the object during an integration time T. The one or more magnetic signals have one or more frequencies. The one or more magnetic signals and the noise signal are detected at six or more magnetic detectors. Relative amplitudes of the magnetic signals are determined. The one or more frequencies of the magnetic signals are substantially equal to frequencies at which a power spectrum of the detected noise signal has zeros.