Patent ID: 7975544

Claim:
A gravity gradiometer for measuring components of gravity gradient tensor, comprising: a sensor for measuring the components of the gravity gradient tensor; a mounting for mounting the sensor for movement about three substantially orthogonal axes; and actuators for moving the sensor on the mounting about the three substantially orthogonal axes, wherein the sensor comprises a first mass, a second mass, a first housing, and a second housing that are configured to be moved by the actuators, the first and second masses being supported within the respective first and second housings for movements relative to the housings in response to the gravitational field, and wherein at least one of the first mass and the second mass also forms an angular accelerometer for detecting angular movement of the sensor and for producing a control signal for application to at least one of the actuators so that the at least one of the actuators applies a torque to the sensor to stabilize the angular movement of the sensor on the mounting.