DocumentCode :
923457
Title :
Reverberation envelope statistics and their dependence on sonar bandwidth and scattering patch size
Author :
Abraham, Douglas A. ; Lyons, Anthony P.
Author_Institution :
Appl. Res. Lab., Pennsylvania State Univ., State College, PA, USA
Volume :
29
Issue :
1
fYear :
2004
Firstpage :
126
Lastpage :
137
Abstract :
Increasing transmit waveform bandwidth in an active sonar-system results in an increase in the signal-to-reverberation power ratio in reverberation-limited environments, but also changes the probability density function of the reverberation envelope. A recent model that relates a description of the sonar system and environment to the parameters of the K-distribution predicts that the shape parameter (α) is proportional to range, beamwidth, and the density of scattering patches on the sea floor and is inversely proportional to bandwidth. In this paper, the bandwidth relationship is examined with real data from a low-frequency active sonar system with a towed array receiver. The inverse proportionality is observed at low bandwidths as a trend away from a Rayleigh-distributed envelope (decreasing α) as bandwidth increases. However, a trend back toward Rayleigh reverberation (increasing α) is observed as bandwidth continues to increase. Hypothesizing that the increase in α arises from over-resolving scattering patches in range and not in angle, the model of is extended to account for patch size relative to that of the sonar-resolution cell. The shape parameter of a moment-matched K-distribution derived from the extended model is then seen to provide a good fit to that estimated from the data.
Keywords :
Rayleigh scattering; acoustic pulses; acoustic wave scattering; probability; sonar arrays; sonar detection; Rayleigh reverberation; Rayleigh-distributed envelope; beamwidth; low-frequency active sonar system; moment-matched distribution; probability density function; reverberation envelope statistics; reverberation-limited environments; scattering patch density; scattering patch size; sea floor; signal-to-reverberation power ratio; sonar bandwidth; sonar-resolution cell; towed array receiver; transmit waveform bandwidth; Bandwidth; Power system modeling; Predictive models; Probability density function; Rayleigh scattering; Reverberation; Scattering parameters; Shape; Sonar; Statistics;
fLanguage :
English
Journal_Title :
Oceanic Engineering, IEEE Journal of
Publisher :
ieee
ISSN :
0364-9059
Type :
jour
DOI :
10.1109/JOE.2004.824039
Filename :
1273568
Link To Document :
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