Satellite altimetry is a particular way of ranging in which the vertical distance betweena satellite and the surface of the Earth is measured (Seeber, 1993). The range betweenthe satellite and the Earth's surface is derived from the traveling time of the radar impulsetransmitted by the radar-altimeter and reflected from the ground. Therefore the method isbest applicable over the oceans, due to the good reflective properties of the water. The signalsare transmitted permanently in the high frequency domain (about 14 GHz) and the receivedecho from the sea surface is used for deriving the round-trip time between the satellite andthe sea. The satellite-to-ocean range is obtained by multiplication of the traveling time ofthe electromagnetic waves with the speed of light and averaging the estimates over a second (Todorova, 2008)