Equivalence of the waveguide invariant and two path ray theory methods for range prediction based on Lloyd’s mirror patterns
Wilson, Jason K.
Rice, Joseph A.
MetadataShow full item record
Previous work discusses the use of normal mode theory as a means of determining the range of a contact from a Lloyd’s Mirror interference pattern. This method relies on the long range interference pattern between different modes. For shallow, range-independent environments where the sound is dominated by low-order modes, the constant which charac- terizes the modal interference pattern, the waveguide invariant, is approximately equal to one. The speed of a contact can be determined from the asymptotic behavior of its tonal frequencies from the Doppler shift. This information can be used along with the change in broadband striation frequencies in a Lloyd’s Mirror pattern over time to extract the range of the contact as it transits through CPA. If instead of using normal mode theory, the Lloyd’s Mirror Pattern is derived as the coherent interference between a straight-line direct and surface-reflected path, a relationship between the striation frequencies and time of a crossing contact can also be derived. This relationship can be shown to be identical to the result obtained from the normal mode approach when the value of the waveguide invariant is equal to one.
Proceedings of Meetings on Acoustics, 155th Meeting Acoustical Society of America, Paris, France, 29 June - 4 July 2008The article of record as published may be found at http://dx.doi.org/10.1121/1.2979233
Showing items related by title, author, creator and subject.
Wilson, Jason K. (Monterey, California. Naval Postgraduate School, 2007-09);Undersea acoustic modems acquire wideband acoustic time series through an electro-acoustic transducer and use on-board digital signal processing for receiving acoustic communications. These component devices can potentially ...
Schulte, Walter B., III (Monterey, California. Naval Postgraduate School, 2004-06);In this thesis, the ocean was modeled as a waveguide with an ideal pressure - release surface, and an ideal rigid bottom. The ocean waveguide was then treated as a linear, time - invariant, space - variant (TISV) filter ...
Echo statistics of individual and aggregations of scatters in the water column of a random, oceanic waveguide Jones, Benjamin A.; Colosi, John A.; Stanton, Timothy K. (2014-07);The relative contributions of various physical factors to producing non-Rayleigh distributions of echo magnitudes in a waveguide are examined. Factors that are considered include (1) a stochastic, range-dependent sound-speed ...