An inflator that supplies gas in the event of a vehicle emergency and a curtain airbag that is inflated and deployed by gas introduction from the inflator are included. The method consists in subjecting the output signals ym from the sensors to complex weights w, said weights w being calculated by maximizing the directivity factor Fd under constraints at low frequencies and in the near field. To this end, a number of next subsequent groups are determined, which fit completely into a FEC frame.