Maximum-Likelihood Flow-Speed Estimation.
Abstract
The design formulae and theoretical performance of a maximum-likelihood estimator for towed-array flow-speed estimation are discussed. Under appropriate conditions, it is shown that a maximum-likelihood estimate of convection velocity (which is related to tow speed) is achieved by performing a cross correlation between the outputs of two streamwise-separated flush-mounted surface probe hydrophones. The estimate, then, is derived by seeking the time delay which maximizes the cross correlation. Conditions are examined consistent with achieving accurate speed determination to within a fraction of a knot. Fortuitously, the method derived has the property that, as speed is increased, both the level and bandwidth of the pressure signals increase, thus providing increased signal-to-noise ratio and more accurate time-delay information.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 24, 1977
- Accession Number
- ADA044681
Entities
People
- F. L. Rees
- S. Gardner