Linear Time-Invariant Space-Variant Filters and the WKB Approximation with Applications to Underwater Acoustic Signal Processing.
Abstract
A mathematical simulation model is developed treating acoustic wave propagation in a random, inhomogeneous ocean as transmission through a linear time-invariant, space-variant random communication channel. The ocean volume is modelled by an index of refraction which is decomposed into a depth dependent deterministic part and a depth-independent Gaussian zero-mean random part. Computer simulated output electrical signals were generated that depend on the complex frequency spectrum of the transmitted electrical signal, the farpfield beam pattern of the transmit array and the random transfer function of the ocean medium. Output was generated for different test cases. In all cases the transmit electrical signal was represented by a finite Fourier series and random cases were modelled by a random number generator. The computer simulated output electrical signals were then processed by a 3-D DFT beamformer and the results for the deterministic inhomogeneous cases were compared to the homogeneous non-random case in order to study the effects of the medium on signal distortion and source localization. Additional keywords: tasks; wave equations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1984
- Accession Number
- ADA154250
Entities
People
- J. Vos
Organizations
- Naval Postgraduate School