Abstract: A magnetic anomaly sensing system and method uses at least four triaxial magnetometer (TM) sensors with each of the TM sensors having X,Y,Z magnetic sensing axes. The TM sensors are arranged in a three-dimensional array with respective ones of the X,Y,Z magnetic sensing axes being mutually parallel to one another. The three-dimensional array defines a geometry that forms at least one single-axis gradiometer along each of the X,Y,Z magnetic sensing axes. Information sensed by the TM sensors is to generate scalar magnitudes of a magnetic anomaly field measured at each of the TM sensors, comparisons of the scalar magnitudes to at least one threshold value, distance to a source of the magnetic anomaly field using the scalar magnitudes when the threshold value(s) is exceeded, and a magnetic dipole moment of the source using the distance.

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 system for tracking a moving magnetic target uses a magnetic anomaly sensing system to continually determine magnetic gradient tensors associated with the target and converts the magnetic gradient tensors to gradient contraction scalars. A processor uses the magnetic gradient tensors and gradient contraction scalars to determine a minimum of bearing and range to the target. A velocity of the target is determined using the determined bearing and range at two points in time as the target is moving. To continually track with the moving target, the processor determines adjustments in elevation and azimuth using the magnetic gradient tensors and gradient contraction scalars along with bearing, range and determined velocities of the target. The processor can include a routine that determines range while accounting for asphericity errors introduced by the aspherical nature of constant magnetic gradient contours associated with the target.

Abstract: A magnetic anomaly homing system and method utilize an array of four triaxial magnetometer (TM) sensors coupled to a non-magnetic platform. The four TM sensors are positioned at the vertices of a rectangular parallelogram. The magnetic field sensed at the four TM sensors is processed to generate complete gradient tensors and corresponding scalar gradient contractions thereof for four two-axis gradiometers formed by the array. The scalar gradient contractions define guidance control parameters used to steer the platform toward the magnetic anomaly.

Abstract: A magnetic anomaly homing system uses an array of magnetic sensors coupled to a non-magnetic platform. The array is defined by a plurality of single-axis subsystems with each one thereof having two magnetic sensors spaced apart from one another. A processor coupled to the magnetic sensors generates a plurality of magnetic total field scalars that can be used to directly home in on a magnetic object from both long and short-range distances to the target. The scalars define guidance control parameters used to steer the platform to align the platforms's direction of motion with the magnetic anomaly.