Underwater acoustic beacon and method of operating same for navigation
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorBenjamin Dzikowicz
Life of this patent
Estimating the term…
Abstract
An underwater acoustic beacon comprises a cylindrical transducer and at least one spiral wavefront transducer aligned along a common central axis. For use in underwater navigation, the cylindrical and spiral wavefront transducers are activated singly and in combination in accordance with a prescribed sequence.
Claims19
An underwater acoustic beacon, comprising:
- a first transducer for generating a signal with a cylindrical acoustic wavefront when activated;
- at least one second transducer for generating a signal with a spiral acoustic wavefront when activated;
- and
- said first transducer and said second transducer aligned along a common axis and acoustically isolated from one another.
An underwater acoustic beacon, comprising:
- a cylindrical transducer having a central axis;
- at least one spiral wavefront transducer having a central axis aligned with said central axis of said cylindrical transducer, wherein each said spiral wavefront transducer comprises:
- a rigid base defining a radial surface that spirals outward a radial distance as said radial surface spirals through one full revolution about said central axis of said spiral wavefront transducer, said radial distance being equal to one full wavelength of a sound wave transmitted in water at a selected frequency;
- and
- a single piezoelectric transducer coupled to said radial surface all along a circumferential length thereof.
An underwater acoustic beacon, comprising:
- a cylindrical transducer having a central axis;
- at least one spiral wavefront transducer having a central axis aligned with said central axis of said cylindrical transducer, wherein each said spiral wavefront transducer comprises:
- a rigid base defining a radial surface that spirals outward a radial distance as said radial surface spirals through one full revolution about said central axis of said spiral wavefront transducer, said radial distance being equal to one full wavelength of a sound wave transmitted in water at a selected frequency;
- and
- a plurality of piezoelectric transducers coupled to said radial surface and spaced apart from one another therealong.
An underwater acoustic beacon, comprising:
- a cylindrical transducer having a central axis;
- at least one spiral wavefront transducer having a central axis aligned with said central axis of said cylindrical transducer, wherein each said spiral wavefront transducer comprises:
- a second cylindrical transducer centrally aligned along said central axis of said spiral wavefront transducer;
- and
- acoustic foam radially encasing said second cylindrical transducer, said acoustic foam having acoustic impedance matched to that of water and having a sound speed of transmission greater than that of water, said acoustic foam defining a radial surface that spirals outward a radial distance as said radial surface spirals through one full revolution about said central axis of said spiral wavefront transducer, said radial distance being equal to one full wavelength of a sound wave transmitted in water at a selected frequency.
A method of operating an acoustic beacon defined by a cylindrical transducer and at least one spiral wavefront transducer aligned with one another along a common axis of radiation, said method comprising the step of activating said cylindrical transducer and said at least one spiral wavefront transducer in accordance with a prescribed sequence during which distinct acoustic signals are generated, said distinct acoustic signals consisting of (i) a first acoustic signal generated solely by said cylindrical transducer, (ii) at least one second acoustic signal generated solely by one of said at least one spiral wavefront transducer, and (iii) a third acoustic signal generated by a combination of said cylindrical transducer and one of said at least one spiral wavefront transducer.
Dependencies are inferred from the claim text.