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 (B , B , B ) of local magnetic fields and components (A , A , A ) of local gravitational acceleration fields. The components (B , B , B ) and (A , A , A ) output from each TMA sensor are processed to generate motion-compensated components (B , B , B ) of local magnetic fields. A difference is generated between the motion-compensated components (B , B , B ) for each pair of TMA sensors thereby generating differential vector field components (B , B ,B ). For improved accuracy, the differential vector field components (B , B , B ) are adjusted using the local gravitational acceleration field components and motion-compensated local magnetic field components in order to compensate for gradiometer motion. Gradient components are generated using the differential vector field components (B , B , B ).