Ship's Speed-Measurement Uncertainties Caused by Localized Water Movements
Abstract
The report analyzes the effects of local water movement on the output of sensors that measure ship's speed relative to water. The four water disturbances considered are surface waves, internal waves, turbulence, and vertical gradients of currents. The effects range from quasi-periodic variations in the indicated speed caused by wave motions to offset errors caused by current changes with depth. The quasi-periodic variations cause difficulty in averaging and sampling the water speed for use in other ship's systems. It is concluded that local water movement does limit the useful accuracy of ship's water speed sensors. Evaluating the magnitude of this limit for any particular ship and sensor and determining the controlling factor will require careful analysis of the specific case and at-sea experimentation to confirm the results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1973
- Accession Number
- AD0769652
Entities
People
- David W Taylor
- Donald R. Laster