The advantages of the GPSplus systems and the RPS system are combined in the DPS system, which offers the highest detection probability at the lowest possible false alarm rate. The system is based on the measurement of pressure differences in the soil which arise when intruders approach and cross the premises. This is combined with the change in the accumulated electromagnetic field caused by the movement of people or vehicles. Detection therefore takes place in a variety of ways, with the signals being processed by the special microprocessor with 'fuzzy logic'. The system is even able to store specific intrusion patterns in its memory for verification. The DPS system can be installed in any soil type except concrete.