A Computer Program for Studying the Doppler Content of Reverberation,

摘要

Torpedoes are the prime conventional antisubmarine weapons and they use acoustic systems to detect the submarine. Some of these systems use frequency dependent characteristics of the returned echo from the submarine to enhance performance. A digital computer program has been developed at the Naval Undersea Center (NUC) which facilitates the analysis of systems that use frequency dependent characteristics. The program is called DOP and is used in conjunction with two other NUC developed programs called SONAR and RAYSRT which are documented in references. This report documents the DOP program. When a single-frequency pulse is emitted from an active sonar system on a moving platform, the reverberation seen by the system is spread due in large part to doppler effects. Program DOP ocomputes the spectrum of such reverberation in a refractive medium. The doppler content is computed as a function of the speed of the sonar platform and (optionally) of circular turning or motion of the scatterers, or both. In addition, the spectrum of the original pulse can be included as a spreading effect, since even a 'single frequency' pulse has a harmonic content due to its finite duration. The energy level is computed in frequency bands of specified width at specified times relative to the transmitted pulse. Four values are computed for each band/time combination: surface, bottom, volume, and total reverberation.