Abstract: This invention concerns gravity gradiometers for airborne surveys for minerals. The gravity gradiometer comprises an inertially stabilized platform, a rotor that is between 0.4 and 1.5 m in diameter mounted in the stabilized platform, and between twelve and seventy two accelerometers arranged in complements of four each on the rotor; and a signal processor operative to: (i) subtract noise calculated from the mass distribution of the aircraft and the inertially stabilised platform, and by the angles of the gimbals of the stabilised platform; (ii) use measures of the accelerations experienced by the gravity gradiometer to estimate the sensitivities of the gravity gradiometer to the acceleration, and use this estimate to correct the gravity gradiometer output; and (iii), use measures of the rotations to which the gravity gradiometer is subjected to calculate the contribution of rotation to the gravity gradiometer noise, and to remove the contribution of rotation to said gravity gradiometer noise.

Abstract: This invention concerns gravity gradiometers for airborne surveys for minerals. The gravity gradiometer comprises an inertially stabilised platform, a rotor that is between 0.4 and 1.5 m in diameter mounted in the stabilised platform, and between twelve and seventy two accelerometers arranged in complements of four each on the rotor; and signal a signal processor operative to: (i) substract noise calculated from the mass distribution of the aircraft and the inertial platform, and by the angles of the gimbals of the stabilised platform; (ii) use measures of the accelerations experienced by the gravity gradiometer to estimate the sensitivities of the gravity gradiometer to the acceleration, and use this estimate to correct the gravity gradiometer output; and (iii), use measures of the rotations to which the gravity gradiometer is subjected to calculate the contribution of rotation to the gravity gradiometer noise, and top remove it.