Underwater Acoustic Imaging: A Simulation Program and Related Theory
Abstract
To aid in the design of a high-resolution sonar (range and transverse resolution approaching 1 mm), a program, POINTSPR, was produced. POINTSPR predicts the image obtained from an active acoustic imaging system with a spherical projector, the target being modelled by a small number of point objects. The waveforms available include chirps and short tonebursts. The receiving elements available include a point and a square piston. A wide variety of receiving array geometries are available, through features including the random placement of elements and the placing of multiple copies of a tile' of elements. Monte Carlo calculations can be run automatically. Sample graphs, which are 1-D or 2-D slices through the 3-dimensional (3-D) image, are given. The theory of image-forming, dechirping and the quadrature part for a real sonar is presented, including delay-and-add' image-forming, known to apply even in the near-field, broadband, 3-D-imaging situation. The report also gives many formulae for image intensity within the simulation model. For a chirp of finite length, certain approximations, often applied, are studied numerically. Formulae, possibly new, are obtained for the response of square elements to a chirp.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2000
- Accession Number
- ADA385015
Entities
People
- David G. Blair
- Stuart D. Anstee