Accession Number:

AD0684151

Title:

ESTIMATING THE PARAMETERS OF AN INHOMOGENEOUS MEDIUM BY PROBING WITH RAYS,

Descriptive Note:

Corporate Author:

RAND CORP SANTA MONICA CALIF

Report Date:

1969-02-01

Pagination or Media Count:

20.0

Abstract:

A computationally efficient technique using ray tracing and successive approximation to estimate the index of refraction of an inhomogeneous medium from the times of arrival of a transmitted signal at various receivers. The ray treatment can cope with a medium whose properties vary in two or three dimensions. The inverse problem can be solved iteratively by a search procedure, by a gradient procedure, or by quadratic convergence. Algorithms for computer solution are presented for quadratic convergence. To conserve high-speed storage, one ray at a time is evaluated until all the rays are considered at each iteration. In a numerical example using fourth-order Adams-Moulton integration with a step size of 0.1, computing time on the IBM 7044 was about half a minute. The initial approximation was a homogeneous medium but the estmate was refined in three iterations. First experiments indicate that the method is feasible even with noisy data. Author

Subject Categories:

  • Acoustics
  • Optics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE