Abstract: Method and systems of controlling detonation of a plurality of explosive charges. A controller has a magneto-inductive transmitter to transmit a magneto-inductive signal to a plurality of detonators, each having a receiver to receive the magneto-inductive signal and a respective firing delay time. The method includes, at each of the plurality of detonators, receiving, via the magneto-inductive signal from the magneto-inductive transmitter, a time sync signal; synchronizing a local clock in the detonator based on the time sync signal; receiving, via the magneto-inductive signal from the magneto-inductive transmitter, a firing code; waiting the respective firing delay time from receipt of the firing code, wherein the waiting is clocked by the local clock; and after expiry of the respective firing delay time, triggering a respective explosive associated with the detonator.

Abstract: A vector sensor for use in acoustic instruments is described. The vector sensor includes: a cylindrical bulkhead partition defining a plurality of channels extending longitudinally on a circumferential wall of the bulkhead partition between a first surface and a second surface of the bulkhead partition; first and second cylindrical piezoelectric transducing pieces affixed to the bulkhead partition and extending outwardly as cantilever beams and contained within respective pressure housing capsules. The sensor may include cylindrical foam end pieces fitted over the capsules and having corresponding channels in their outer surfaces that correspond to channels in the bulkhead partition, so as to allow wiring and strength members to pass through. The cylindrical piezoelectric transducing pieces may be formed from a piezoelectric cylindrical tube with a first electrode covering its inner surface and a second electrode on its outer surface.

Abstract: An underwater acoustic projector system that includes a linear array of acoustic projectors in close proximity such that the acoustic projectors interact with one another when they produce acoustic pressures, wherein each acoustic projector in the linear array is spaced apart from an adjacent acoustic projector by a respective distance, and wherein the respective distance between two acoustic projectors proximate the center of the linear array is greater than the respective distance between two acoustic projectors proximate the end of the linear array.

Abstract: A vector sensor for use in acoustic instruments is described. The vector sensor includes: a cylindrical bulkhead partition defining a plurality of channels extending longitudinally on a circumferential wall of the bulkhead partition between a first surface and a second surface of the bulkhead partition; first and second cylindrical piezoelectric transducing pieces affixed to the bulkhead partition and extending outwardly as cantilever beams and contained within respective pressure housing capsules. The sensor may include cylindrical foam end pieces fitted over the capsules and having corresponding channels in their outer surfaces that correspond to channels in the bulkhead partition, so as to allow wiring and strength members to pass through. The cylindrical piezoelectric transducing pieces may be formed from a piezoelectric cylindrical tube with a first electrode covering its inner surface and a second electrode on its outer surface.

Abstract: A method and towed sonic array system for defocusing the beampattern of the towed sonic array. The method includes determining an amplitude adjustment and a phase adjustment for each of the sonic projectors; and driving each of the sonic projectors with a drive signal modified by the amplitude adjustment and the phase adjustment for that sonic projector. The amplitude adjustment and phase adjustment for each of the sonic projectors are, at least in part, based upon the distance from that sonic projector to a virtual source. The location of the virtual source may be selected so as to achieve different beampatterns, including wide-sector beams and, in at least one case, a near-omni-directional beampattern. The drive signal may include multiple frequency components, in which case the method may be used to find a set of beamformer coefficients for each of the frequency components and an inverse transform may be used to realize a defocused driving signal.

Abstract: An underwater acoustic projector system that includes a linear array of acoustic projectors in close proximity such that the acoustic projectors interact with one another when they produce acoustic pressures, wherein each acoustic projector in the linear array is spaced apart from an adjacent acoustic projector by a respective distance, and wherein the respective distance between two acoustic projectors proximate the center of the linear array is greater than the respective distance between two acoustic projectors proximate the end of the linear array.

Abstract: A method and system for maximizing radiated power from a linear array of acoustic projectors. In one case, the method realizes omni-directional acoustic beam patterns from a linear array of acoustic projectors contained within an acoustically-impervious enclosure with an acoustically transparent aperture. In another case, the method realizes an efficient set of beams for a conventional horizontal projector array or a similar acoustic projector array, which may be within an acoustically transparent enclosure. Drive signals are determined by finding a mutual impedance matrix that characterizes the interdependence of the acoustic projectors and solving an eigenvalue problem for the mutual impedance matrix. One of the eigenvalues is selected on the basis that it maximizes radiated power, and the corresponding eigenvectors are used to derive the corresponding drive signals.

Abstract: A method and system for locating the position of a source that emits a rotating magnetic field. Three or more receivers are deployed or positioned in known position relative to each other, which may be along a common axis in some cases. Phase differences between the magnetic fields measured by the receivers are detected. The phase shifts are used to determine the location of the source. With three receivers, a range and bearing angle relative to a middle receiver may be determined. With five or more receivers, a range and two bearing angles may be determined, thereby providing a three-dimensional position.

Abstract: A method and system for maximizing radiated power from a linear array of acoustic projectors. In one case, the method realizes omni-directional acoustic beam patterns from a linear array of acoustic projectors contained within an acoustically-impervious enclosure with an acoustically transparent aperture. In another case, the method realizes an efficient set of beams for a conventional horizontal projector array or a similar acoustic projector array, which may be within an acoustically transparent enclosure. Drive signals are determined by finding a mutual impedance matrix that characterizes the interdependence of the acoustic projectors and solving an eigenvalue problem for the mutual impedance matrix. One of the eigenvalues is selected on the basis that it maximizes radiated power, and the corresponding eigenvectors are used to derive the corresponding drive signals.

Abstract: A method and towed sonic array system for defocusing the beampattern of the towed sonic array. The method includes determining an amplitude adjustment and a phase adjustment for each of the sonic projectors; and driving each of the sonic projectors with a drive signal modified by the amplitude adjustment and the phase adjustment for that sonic projector. The amplitude adjustment and phase adjustment for each of the sonic projectors are, at least in part, based upon the distance from that sonic projector to a virtual source. The location of the virtual source may be selected so as to achieve different beampatterns, including wide-sector beams and, in at least one case, a near-omni-directional beampattern. The drive signal may include multiple frequency components, in which case the method may be used to find a set of beamformer coefficients for each of the frequency components and an inverse transform may be used to realize a defocused driving signal.