Patent ID: 6883372

Claim:
A gravity gradiometer for airborne surveys for minerals, comprising 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 a signal processor operative to: (i) subtract noise calculated from a mass distribution of an aircraft and the inertially stabilised platform, and by angles of gimbals of the stabilised platform; (ii) use measured accelerations experienced by the gravity gradiometer to estimate the sensitivities of the gravity gradiometer to the accelerations, and use the estimate to correct a gravity gradiometer output; and (iii) use measured rotations to which the gravity gradiometer is subjected to calculate a contribution of rotation to a gravity gradiometer noise, and to remove the contribution of rotation to said gravity gradiometer noise.