Patent attributes
The present invention provides a gravity gradiometer for measuring components of the gravity gradient tensor. The gravity gradiometer includes at least one sensor mass for movement in response to a gravity gradient and a sensor and actuator unit for generating an electrical signal in response to the movement of the at least one sensor mass and for influencing the movement of the at least one sensor mass. The gravity gradiometer also includes an electronic circuit for simulating an impedance. The electrical circuit is arranged for amplifying the electrical signal received from the sensor and actuator unit and for directing an actuating signal to the sensor and actuator unit. The electronic circuit includes a differential amplifiers having first and second amplifier input terminals and an amplifier output terminal and impedances Z1, Z2, Z3, at least one of the impedances have an imaginary impedance component.
