Abstract: A portable magnetic anomaly sensing system includes a non-magnetic support structure defined by a rigid beam and a rigid frame coupled thereto. Triaxial magnetometer (TM) sensors are rigidly coupled to the frame with one TM sensor being positioned at each vertex of a cubic space. Each TM sensor is positioned such that all respective X,Y,Z magnetic sensing axes are mutually parallel to one another. A data acquisition system is mechanically coupled to the beam such that any magnetic elements of the data acquisition system do not adversely affect accuracy of the TM sensors. The data acquisition system samples the sensed magnetic field data from all TM sensors synchronously with a timing signal. A processor is mechanically coupled to the beam such that any magnetic elements of the processor do not adversely affect accuracy of the TM sensors.

Abstract: A magnetic anomaly sensing system and method uses at least eight triaxial magnetometer (TM) sensors arranged to define a cubic space. Each TM sensor measures a local magnetic field associated with a target region and generates magnetic field data indicative thereof. The magnetic field data is processed in accordance with a magnetic scalar triangulation and ranging (STAR) processing scheme to determine a plurality of gradient contractions CT,I at a corresponding plurality of measurement points I to include at least at the center of each face of the cubic space. Gradient contraction pairs are defined for each sensors' X, Y, Z magnetic sensing axes. A directional derivative ?CT is determined using the gradient contraction pairs and the baseline distances therebetween. A unit vector, calculated using the directional derivative ?CT, is used in determining a projection distance from each of the measurement points toward the target region.

Abstract: A method is provided for along-track displacement of an underwater vehicle equipped with a synthetic aperture sonar (SAS) system. The SAS system is operated as the vehicle moves through the water. Using successively-detected acoustic signals, an actual redundant phase center overlap scenario is determined that is indicative of along-track displacement of the underwater vehicle occurring between the successively-detected acoustic signals.

Abstract: A method is provided for determining multiple feature variances in a medium. Acoustic sources are positioned on one side of a selected scattering direction. Acoustic receivers are positioned on an opposite side of the selected scattering direction such that, for each acoustic source, there is a corresponding acoustic receiver located at a mirror-imaged position relative to the selected scattering direction, and such that a Bragg scattering wave vector associated with each acoustic source/receiver pair is parallel to the selected scattering direction. Each acoustic source is operated at a unique time to direct a broadband ultrasonic pulse at the region of interest. An acoustic scattered wave reflects from the region of interest and is detected as a waveform at the pair's acoustic receiver. Each waveform is converted to the frequency domain to form a spectral waveform. A band of Bragg wave numbers is determined for each spectral waveform.

Abstract: The present invention relates to a system for studying, identifying and cacterizing thermal gradients within a volume of water. The system includes a frame formed from a plurality of PVC tubing sections and connectors. The connectors are used to house at least one pair of acoustic transducers, which transducers are used to collect data for studying, identifying and characterizing the thermal gradients within the volume of water. A number of different frame configurations may be used to perform a number of different studies.

Abstract: The present invention relates to a system for studying, identifying and cacterizing thermal gradients in a volume of water. The system includes a frame for supporting one or more measuring devices and a source of heat for generating a thermal plume in the volume of water. The frame includes a first plate to which the measuring devices are mounted by a plurality of mounting blocks spaced about the periphery of a hole in the first plate. The frame further includes a second plate, spaced from the first plate, to which the source of heat is mounted.