The Effect of Ship Motion on Ship Magnetic Signature
Abstract
The effects of roll, pitch and yaw motions on a ship's magnetic signature are investigated. These three modes of rotary motion, each simple harmonic, are treated as uncoupled and a dipole model representation is used to describe the ship's magnetization. Signatures are computed for a model ship assumed, for simplicity, to be bearing due magnetic North and compared with the steady-state signatures (for no rotary motion). Oscillatory magnetic field components result from these ship motions which decrease in significance, compared to the steady-state fields, as the observation point is moved further away from the ship's passage. These field deviations decrease more rapidly with a beam displacement than with depth. Variation with ship speed is more complicated and depends critically on the values assigned for the amplitudes, frequencies, and relative phases of the three modes of motion. In high sea states the magnetic signatures can vary considerably from those in calm seas with implications for magnetic-influence mine actuation. Keywords: Ship signatures; Magnetic signatures; Sea state; Australia; Ship motion.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1988
- Accession Number
- ADA200045
Entities
People
- C. J. Akenfelds
- Philip J. Ryan
Organizations
- Defence Science and Technology Group