A new estimator of the sea state bias using a three frequency radar altimeter

This work deals with the estimation of the sea state bias (SSB). We performed a method to compute an altimeter return waveform from a deterministic sea surface [Amarouche et al. 2000]. To simulate the SSB, the sea surface characteristics and the electromagnetic model have been modified in agreement with statistical and physical theories and observations [Amarouche et al. 2000]. The conclusions of this study allow us to propose an estimator of the SSB using three frequency bands. Our simulator is tested using the performance budgets of Poseidon-2 (C and Ku bands) and AltiKa (Ka band) radar altimeters. The SSB is estimated with a bias of the order of about one millimeter and a noise of the same order of magnitude as the height estimation noise. The importance of the significant wave height estimation in determining the SSB, led us to propose a method to improve this estimation by studying the point target impulse response approximation by a Gaussian shape in the waveform model.