Accession Number : ADC023527


Title :   Acoustic Signal Characteristics Measured with the LAMBDA III During CHURCH STROKE III


Descriptive Note : Technical note


Corporate Author : NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS


Personal Author(s) : Gereben, Istvan B ; Carey, William M ; Doolittle, Richard D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/c023527.pdf


Report Date : 15 Sep 1980


Pagination or Media Count : 159


Abstract : Exercise CHURCH STROKE III, CRUISE I was designed to update the understanding of ocean acoustic parameters and their effects on passive acoustic surveillance systems in the Florida Channel of the Straits of Florida, the northern end of the Yucatan Channel and the Eastern Gulf of Mexico. Data acquisition for the determination of signal characteristics was accomplished with the Large Aperture Marine Basic Data Array III (LAMBDA III). The analysis of the signal data and supporting information produced the following major results: When the influence of the slope was absent measured transmission loss showed good agreement with the FACT Model employing medium to low bottom loss curves: Slope enhancement effect was observed when the source, preceding from deep water towards the slope, reached the location of the initiation of the slope; Array signal gain ranged from 15 dB to 34 dB; it was determined that in this multipath environment towed array performance is affected by array signal gain and its fluctuations; Statistical distribution of ASG was found to be Log Normal Distribution when the multipath environments were not changing rapidly; Half power beam width was determined as 1.73 + or - 0.35 deg; Side lobe levels near the signal beam were determined as -9 dB for the first lobe and -17 dB for the second lobe; Beam Width and side lobe levels were comparable to theoretical values for the prevailing operational condition of the array; and Signal coherence over the array aperture was established for high signal to noise ratio cases; the average MSC value was approximately 70%.


Descriptors :   *UNDERWATER ACOUSTICS , *UNDERSEA SURVEILLANCE , *ACOUSTIC SURVEILLANCE , BATHYMETRY , SEA TESTING , MILITARY EXERCISES , CALIBRATION


Subject Categories : Physical and Dynamic Oceanography
      Acoustic Detection and Detectors


Distribution Statement : APPROVED FOR PUBLIC RELEASE