Patent ID: 7444867

Claim:
A gravity gradiometer comprising: an accelerometer operable to measure an acceleration along an input axis, the accelerometer mounted such that the input axis is parallel to an axis of rotation of the gravity gradiometer; one or more angular rate sensors operable to measure an angular rate along an input axis, the one or more angular rate sensors mounted such that each input axis of the one or more angular rate sensors is orthogonal to each other; a disc that rotates about the axis of rotation of the gravity gradiometer; and two pairs of accelerometers mounted on the disc such that input axes of the two pairs of accelerometers are perpendicular to the axis of rotation and tangent to a circumference of the disc, wherein the accelerometer operable to measure the acceleration along the input axis and mounted such that the input axis is parallel to the axis of rotation of the gravity gradiometer is not one of the paired accelerometers.