Patent ID: 8909496

Claim:
A method of determining a bias-corrected value of at least one component of a gravity gradient tensor, the method comprising: a) using a gravity gradiometer positioned in a first orientation to take a first measurement of at least one component of the gravity gradient tensor, wherein the first measurement is taken at a first time; b) using the gravity gradiometer positioned in a second orientation to take a second measurement of at least one component of the gravity gradient tensor, wherein the second measurement is taken at a second time; c) using the gravity gradiometer to take a third measurement of at least one component of the gravity gradient tensor, wherein the third measurement is taken at a third time, wherein, for the third measurement, the gravity gradiometer is positioned in one of the first orientation, the second orientation, and a third orientation; d) determining a measurement bias of the gravity gradiometer based on the first, second, and third measurements, wherein the measurement bias varies with time; and e) determining the bias-corrected value of at least one component of the gravity gradient tensor based on the first, second and third measurements.