A method for determining a relative dielectric constant of a ground to be searched for mines using a detector including at least one detection coil and a ground penetrating radar including at least one transmitter antenna and at least one receiver antenna and a detection method for detecting metal and non-metal objects in a ground using a mine detector including a metal detector and a ground penetrating radar, wherein the metal detector includes at least one detection coil with a coil plane which is moved parallel to the ground during detecting, and wherein the ground penetrating radar includes an antenna arrangement including at least one transmitter antenna and at least one receiver antenna. The method according to the invention for determining a relative dielectric constant enables a user to calibrate the detector quickly and in a known manner with respect to ground properties of the ground to be searched.