Fiĺtering of a large portion of Geos 3 satellite radar altimetry data at the Naval Surface Weapons Center has been accomplished by a Wiener smoother. The statistics of the geoid for the Wiener smoother is based on a third-order Markov process. Because of some limitations the Wiener smoother has been replaced by a Kalman smoother which satisfies more closely the conditions of the altimetry data. The Kalman smoother also uses the same third-order Markov statistics. A discussion of the smoothers (filter models), results obtained from the models, and a comparison of results with ship survey data are given in this paper.