SHIP'S SPEED-MEASUREMENT UNCERTAINTIES CAUSED BY LOCALIZED WATER MOVEMENTS

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. (Author)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/NSRDC27446
• Corporate Authors:

  Naval Ship Research and Development Center

  Bethesda, MD  United States  20034
• Authors:
  • Laster, D R
• Publication Date: 1973-10

Media Info

• Pagination: 33 p.

Subject/Index Terms

• TRT Terms: Errors; Graphics; Inertial navigation systems; Internal waves; Numerical analysis; Ocean waves; Rayleigh waves; Ship motion; Ships; Speed; Speed measurement; Turbulence; Uncertainty; Velocity; Waves
• Old TRIS Terms: Ship speed prediction; Surface wave effects; Wave effects
• Subject Areas: Design; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00051760
• Record Type: Publication
• Source Agency: National Technical Information Service
• ISBN: NSRDC-27-446
• Report/Paper Numbers: NSRDC-3942 R&D Rpt
• Files: TRIS
• Created Date: Mar 25 1974 12:00AM