State-Space Models of Gravity Disturbance Gradients
Stanley K. Jordan, Peter Moonan, J. Weiss · IEEE Transactions on Aerospace and Electronic Systems · 1981
State-space models of gravity disturbance gradients are needed to design the Kalman filters used for gradiometer-aided inertial navigation. However, the physics of the gravity field guarantee that many of the cross-spectral densities of gravity disturbance gradients are nonrational. A procedure is demonstrated for fitting gravity disturbance correlation functions with finite-dimensional state-space models.