Near real time estimation of vertical deflections at sea

In this paper a world-wide applicable technique for recovering vertical deflections at sea using the astrogeodetic technique has been developed. It involves using the difference between the astronomic source, the Integrated Inertial System and Star Tracker, and the geodetic source, the NAVSAT as basic measurements. Then a spatial interpolation technique is applied to the spatially dispersed basic measurements to estimate vertical deflections everywhere in the area. Optimal Kalman smoothing involving star tracker damping and EM Log damping is applied to improve estimation capability for post test time applications. The technique was evaluated theoretically and empirically in an at-sea test performed on the U. S. Vanguard which contained all the required navigation devices.