USA As Represented by Secretary of the Navy

John F Scarzello

John J Holmes

Edward C O'Keefe

Daniel S Lenko

Albert D Krall

Albert M Syeles

Robert Andrew Wingo

Richard W Harrison

Adam C Feaga

Wayne R Grine

Robert E Brown

Milton K Mills

John W McCorkle

Jack Finkel

Peter B Keller

Bruce R Hood

George W Usher

A plurality of sensing modules are deployed by positioning thereof in spaced relation to each other on a seafloor surface at a shallow depth to establish a targeted seawater zone within which certain conditions are detected, such as those produced by the presence of a sea vessel such as a submarine within the targeted zone. Data signals are generated within the deployed sensing modules in response to said detection of the submarine for radio frequency transmission above the seawater targeted zone from floating transmitters ejected from the sensing modules positioned on the seafloor surface after detection of the submarine.

Underwater surveillance system

An elongated optical fiber is vertically positioned within seawater in a deep-depth targeted zone by vertical suspension thereof from a floating buoy. Electrode sensor arrays are positioned in vertically spaced relation to each other on the optical fiber for generating warning signals in response to detection of hostile conditions. The warning signals are converted into signal data collected and transferred to a transmitter in the floating buoy from which the sensor arrays are suspended within the targeted zone positioned on the optical fiber. Such collected data signals are transmitted through an antenna within the floating buoy to locations above the seawater surface for surveillance purposes.

Deep water surveillance system

The electromagnetic field produced by an electrical device is electromagnetically canceled by a three-dimensional configuration of electrical coils which together provide a box-like enclosure having at least six sides/faces. The electromagnetic containment of the electromagnetic field is effected via the physical occurrence of zero magnetic flux perpendicularly through each side/face. At least one coil is positioned in correspondence with each side/face of the box-like enclosure. Each coil has a set of conductors divided into two halves in terms of circuitry, the conductors in each half being connected to each other in series. With regard to each coil, a first amplifier receives an electrical signal from the first conductor half and outputs to a second amplifier a voltage signal proportional to the AC magnetic flux through the coil. The second amplifier inputs a current signal to the second conductor half so as to render nonexistent the first amplifier's output voltage signal.

Power frequency electromagnetic field compensation system

A method and apparatus for detecting and deterring underwater threats is provided that uses numerous anodes and sensors around a ship or other waterborne structure to monitor for intruders and issue electrical shocks to the intruders in increasing amounts to deter sabotage. The underwater detection and deterrent system would provide an alarm and the approximate location of the intruder when the electrical field changes in response to the intruder. The system is capable of providing a lethal electrical shock to the intruder if necessary.

Underwater detection and deterrent system

Gradiometers are encompassingly disposed, relative to an object of interest, in a configuration generally describing a closed prolate spheroidal shape, and the measurements taken by the gradiometers are mathematically processed. The gradiometric measurements are defined as directional derivatives which exist in equations involving directional derivatives and prolate spheroidal multipole moments of said entity. The prolate spheroidal multipole moments are thereby calculated, and these prolate spheroidal multipole moment values are extrapolated to ascertain the magnetic fields (equivalently expressed, the magnetic signatures) associated with the object and inwardly delimited by the prolate spheroid. The practitioner can optimize such distribution numerically, orientationally and/or positionally by using the equations involving directional derivatives and prolate spheroidal multipole moments. Extraneous magnetic field effects (e.g., applied fields, earth fields) are inherently excluded, thus obviating the object's removal from an electromagnetic test facility.

Gradiometric measurement methodology for determining magnetic fields of large objects

A magnetic field sensor, for sensing the transverse component of the magnetic field intensity H, is based on fluxgate magnetometric principles and includes an &ldquo;E&rdquo;-shaped magnetic core. A drive winding is wound about the medial leg of the &ldquo;E&rdquo; shape. A sense winding is wound about the base of the &ldquo;E&rdquo; shape at the two locations between the medial leg and the extreme legs. A calibration winding is wound about each leg. Another magnetic field sensor, for sensing the normal component of the magnetic induction B, is also based on fluxgate magnetometric principles and includes a magnetic core having a sort of coaxial double cylindrical configuration wherein a basket-shaped cylinder encloses a smaller, solid cylinder. A drive winding, then a sense winding, then a calibration winding are wound over the solid cylinder. During operative placement of either inventive sensor in appropriate relation to a ferromagnetic surface, a closed magnetic flux path is manifested through the sensor and the ferromagnetic material; in effect, the ferromagnetic material is made a part of the sensor's transducer core.

Fluxgate magnetic field sensor incorporating ferromagnetic test material into its magnetic circuitry

A magnetic field sensor based on fluxgate magnetometric principles includes a magnetic core having a highly elongated oblong configuration and accordingly defining a closed magnetic flux path. The core includes flexible amorphous magnetic material. A drive winding is wound about each of two linear sections of the core. The two drive winding-wound linear core sections are closely coupled in parallel adjacent disposition. A sense winding is wound about the drive winding-wound core, thereby forming a narrow unitary strip-like sensor construction which, depending on the embodiment, can be practically any length. Typically, a very long sensor is situated huggingly or abuttingly with respect to a great expanse of a ferromagnetic material surface. The sensor is capable of generating a detectable signal which is representative of the &ldquo;integration&rdquo; of magnetic field components over the length of the core. The invention's integrative function minimizes measurement skewing or distortion attributable to anomalous characteristics of the ferromagnetic material being sensed. The invention's &ldquo;integrative&rdquo; sensor admits of systematic association with any number and diverse kinds of &ldquo;point&rdquo; sensors, in furtherance of more complete data acquisition.

Spatially integrating fluxgate manetometer having a flexible magnetic core

The invention uniquely avails of Fourier analytical principles for determining the distribution of a magnetic field in a one-dimensional (linear), two-dimensional (planar) or three-dimensional (spatial) region of interest. According to many embodiments, integrating sensor apparatus having an associated length is inventively implemented so as to measure the magnetic field amplitude value for each of two or more different points. Alternating current is applied at at least one high frequency whereby, for each such frequency, the associated wavelength corresponds to some multiple of the sensor's length. Coiled around the sensor is/are one or more solenoids which is/are configured so as to establish a standing wave along the sensor's length. Inventive adaptation of the sensor's integrating function basically entails regarding a Fourier-type harmonic bias function as being consequential of the standing wave. A Fourier coefficient is thus inventively found for each selected multiple of the sensor's length. The invention is especially advantageous because a single inventive sensor is capable of measuring a magnetic field distribution of virtually unlimited expanse, the extensiveness of which would conventionally require a multiplicity of arrayed sensors.

Standing wave magnetometer

A magnetic field sensor based on fluxgate magnetometric principles includes a magnetic core having an elongated oblong configuration and accordingly defining a closed magnetic flux path. The core includes a rigid bobbin which defines the core's shape, and about which amorphous magnetic material is wrapped. A drive winding is wound about each of the two parallel linear sections of the core. A sense winding is wound about another rigid bobbin which surrounds the drive winding-wound core. Typically, a feedback winding is wound about another rigid bobbin which surrounds the sense winding. When, for sensing purposes, the driven sensor is situated near and parallel to a ferromagnetic material surface, the sensor is capable of generating a detectable signal which is representative of the &ldquo;integration&rdquo; of magnetic field components over the length of the core. The invention's integrative function minimizes measurement skewing or distortion attributable to anomalous characteristics of the ferromagnetic material being sensed.

Integrating fluxgate magnetometer

An improved detector is provided for installation in a roadway surface. The detector finds utility in a highway vehicle detection system for determining vehicle presence, vehicle speed and vehicle length. First and second matched induction coil magnetic sensors are maintained at or near the roadway surface. Each of the sensors has a longitudinal axis aligned normal to the roadway surface. The first and second sensors are separated from one another by a known distance in a direction substantially aligned with a direction of traffic flow. Each of the sensors generate a differential magnetic field signature with respect to time to indicate a passing vehicle's leading and trailing edge magnetic signatures. Vehicle speed is determined by a time-distance relationship using the leading and trailing edge magnetic signatures and the known distance. Vehicle length is determined by a time-speed relationship using the leading and trailing edge magnetic signatures and the determined vehicle speed. A triaxial magnetometer maintained at a location in close proximity to the first and second sensors measures a DC magnetic field. The DC magnetic field has vertical and horizontal magnetic field components with the horizontal components including a component substantially aligned with the direction of traffic flow and a component substantially perpendicular to the direction of traffic flow. The vertical and horizontal components caused by the passing vehicle are used to determine vehicle presence. An ELF communications system may be incorporated with the detector to link roadside and vehicle transmitted/received information.

Vehicle presence, speed and length detecting system and roadway installed detector therefor

A detection and classification system for underwater objects uses a transting unit and a receiving unit. The transmitting unit comprises a waveform generator, a power amplifier, and a transmitting antenna. The receiving unit comprises a receiving antenna, a pre-amplifier, a first harmonic suppressor, a digitizer, and a computer. The transmitting unit radiates an analog electromagnetic wave signal into a conductive medium such as seawater which the receiving unit detects and analyzes by a differential spectral analysis after conversion of the signal into binary code. The system uses a signal-processing method which includes the steps of determining the size of the underwater object to be detected, transmitting an electromagnetic wave with a wavelength proportioned to the size of the object, performing a spectral analysis of the received signal, performing a spectral analysis at a different time or different location, comparing the two spectra performed, and analyzing the difference between the two spectra.

Submerged object detection and classification system

A mine sweeping system including deployable horizontal antennas to establ a detection and navigation grid extending underwater from a beach to a distance offshore. A computer-controlled transmitter unit having a waveform generator and amplifier, transmits signals to each antenna, at unique frequencies and phases for different spatial locations within the grid. An autonomous underwater vehicle having multi-integrated sensors detects anomalies in the electromagnetic field caused by both magnetic and non-magnetic objects therein during underwater travel utilizing the electromagnetic field as a navigational grid. The autonomous underwater vehicle also deposits mine-clearing explosives at each magnetic anomaly for detonation under command signal using the horizontal antennas which provide a means for establishing a navigation grid to permit landing craft and other vessels to navigate in the region cleared of mines.

Mine sweeping system for magnetic and non-magnetic mines

A portable electromagnetic field exposure dosimeter includes a triaxial fite-loaded coil sensor, a group of amplifiers and bandpass filters, a data control board, and a computer. The triaxial sensor receives electromagnetic radiation along three orthogonal axes for measurement which is channelled through a group of amplifiers and then bandpass filtered into three frequency signal ranges. One frequency range corresponds to exposure at 60 Hz and two of its harmonics. The second frequency range corresponds to high frequency pulsed energy. The third frequency range reflects body motion of a tested individual. The data control board converts such filtered signals into digital code and controls the flow of the converted data to random access memory and to the computer. The computer performs a Fast Fourier Transform on the converted data from the 60 Hz frequency range and then stores or displays the analyzed data as a function of frequency and time. The computer also stores or displays the data from the other two frequency ranges.

System for monitoring and analyzing field energy exposure

An optical fiber magnetometer having omnidirectional capability is disclo herein for measuring a total magnetic field independent of its physical orientation or the direction of the field or fields. A relatively long optical fiber defining a sensing arm for exposure to a magnetic field is wound in the form of a spheroid (like rubber bands on a golf ball or yarn threads on a baseball) to provide optical path lengths of substantially the same total length in every direction through the spheroid winding. The plane of polarization of light transmitted through the optical fiber winding is caused to rotate (Faraday effect) when the fiber or components thereof is exposed parallel to a magnetic field. The extent of plane rotation is determined, inter alia, by the total magnetic field passing through the spheroid winding.

Optical fiber magnetometer

An electrically short, omnidirectional antenna formed with a strip conduc helically wound about the outside of a cylindrical ground plane. A layer (ideally, a very thick layer) of a nonconducting material preferably with a low dielectrical constant (i.e., .epsilon..sub.r .perspectiveto.1.0) separates the microstrip from the ground plane.

Growing community of inventors

Columbia, MD, United States of America

John F Scarzello