Abstract: A magnetic anomaly sensing system and method uses two triaxial magnetometer (TM) sensors arranged in a one-dimensional array with the sensors' magnetic sensing axes being parallel to one another. The sensors are spaced-apart from one another along one of the sensing axes by a distance D with a midpoint between the sensors along the one sensing axis being located a distance Z from a reference datum. A processor implements an iterative process to include generating scalar magnitudes of a magnetic anomaly field measured at each of the sensors where the magnetic anomaly field is associated with a magnetic object. A scalar range from the sensors to the magnetic object is generated based on the distance D, the distance Z, and the scalar magnitudes. A magnetic dipole moment of the magnetic object is generated using the scalar range and the scalar magnitudes.

Abstract: A magnetic anomaly surveillance system includes triaxial magnetometer (TM) sensors arranged at known locations in an array. A processor coupled to the TM sensors generates a scalar magnitude of a magnetic anomaly field measured at each of the TM sensors. The scalar magnitude is indicative of a spherical radius centered at the known location associated with a corresponding one of the TM sensors. The processor also generates a comparison between each scalar magnitude and a threshold value. The processor then determines at least one magnetic anomaly location in the coordinate system via a spherical trilateration process that uses each spherical radius and each scalar magnitude associated with selected ones of the TM sensors for which the threshold value is exceeded. One or more output devices coupled to the processor output data indicative of the one or more magnetic anomaly locations.

Abstract: A system and method for magnetic anomaly guidance is provided. Triaxial magnetometer (TM) sensors are positioned at the vertices of an arrangement with an axis of the arrangement, being defined between each pair of the vertices. The arrangement is positioned on a support such that one of the X,Y,Z magnetic sensing axes for all of the sensors defines a forward direction of movement. The sensed magnetic field's X,Y,Z components of the TM sensors are processed to generate a partial gradient contraction associated with each axis of the sensor arrangement. Relationships between the partial gradient contractions are used to generate steering control commands for use by a steering system that is coupled to the support.

Abstract: A magnetic anomaly sensing system uses triaxial magnetometer (TM) sensors arranged in a three-dimensional array. A processor coupled to the TM sensors generates partial gradient contraction data, and complete gradient tensor data and corresponding complete gradient contraction data. The generated data can be used to align the three-dimensional array with a magnetic target. Once the three-dimensional array is aligned with the magnetic target, the generated data can be used to uniquely determine (i) distance to the magnetic target, (ii) position of the magnetic target relative to the three-dimensional array, and (iii) the magnetic dipole moment of the magnetic target.

Abstract: An active magnetic anomaly sensing and processing system has a plurality of transceivers positioned at known relative positions on a platform. Each transceiver includes i) a transmitter for transmitting a magnetic field towards a target to cause propagation of a magnetic anomaly field from the target, and ii) a sensor that produces a first output indicative of the magnetic anomaly field and background magnetic fields. A reference sensor, positioned further from the target than each of the transceivers' sensors, senses background magnetic fields and produces a second output indicative thereof. Each transmitter is activated and subsequently deactivated simultaneously to define a transmission time and a non-transmission time, respectively. Scalar magnitudes of each first output and the second output produced during the non-transmission time form quantities that are indicative of presence, location and classification of the target.

Abstract: A system and method for sensing magnetic anomalies uses a gradiometer having at least one pair of triaxial magnetometer-accelerometer (TMA) sensors. Each TMA sensor has X,Y,Z magnetic sensing axes and X,Y,Z acceleration sensing axes that are parallel to one another and to the X,Y,Z magnetic sensing and acceleration axes of all other TMA sensors. Each TMA sensor outputs components (Bx,By,Bz) of local magnetic fields and components (Ax,Ay,Az) of local gravitational acceleration fields. The components (Bx,By,Bz) and (Ax,Ay,Az) output from each TMA sensor are processed to generate motion-compensated components (Bcx,Bcy,Bcz) of local magnetic fields. A difference is generated between the motion-compensated components (Bcx,Bcy,Bcz) for each pair of TMA sensors thereby generating differential vector field components (&Dgr;Bx,&Dgr;By,&Dgr;Bz).

Abstract: A system and method for sensing magnetic anomalies uses a gradiometer having at least one pair of triaxial magnetometer-accelerometer (TMA) sensors. Each TMA sensor has X, Y, Z magnetic sensing axes and X, Y, Z acceleration sensing axes that are parallel to one another and to the X, Y, Z magnetic sensing and acceleration axes of all other TMA sensors. Each TMA sensor outputs components (Bx, By, Bz) of local magnetic fields and components (Ax, Ay, Az) of local gravitational acceleration fields. The components (Bx, By, Bz) and (Ax, Ay, Az) output from each TMA sensor are processed to generate motion-compensated components (Bcx, Bcy, Bcz) of local magnetic fields. A difference is generated between the motion-compensated components (Bcx, Bcy, Bcz) for each pair of TMA sensors thereby generating differential vector field components (&Dgr;Bx, &Dgr;By,&Dgr;Bz).

Abstract: An active magnetic anomaly sensing system includes a transmitter for transmitting a magnetic field towards a target. The magnetic field induces magnetic moments in the target which cause a magnetic anomaly field to propagate from the target. A first sensor positioned a distance D from the target directly senses magnetic field strength and produces a first output. A second sensor positioned a distance (D+d) from the target directly senses magnetic field strength and produces a second output. A controllable power supply is coupled to the transmitter for selectively activating and deactivating the transmitter. The first and second outputs are produced when the transmitter is deactivated. The second output is subtracted from the first output to generate a differential output indicative of the magnetic anomaly field propagating from the target.