FREMGANGSMAATE OG ANORDNING TIL PAAVISNING AV FARTOEYER.

摘要

If operating noise radiated from a ship is received and stands out against a general background noise, a ship is detected. A problem is presented by detection at low signal-to-noise ratio. In order to achieve a greater reliability of detection even in that case, a method is provided in which the noise received is examined in relation to the pattern of its envelope with respect to time and a ship is only detected if the pattern with respect to time exhibits variations which are characteristic of an amplitude-modulated noise. A device for implementing the method is provided which can be used particularly advantageously in underwater sound technology in panoramic level indicating systems.