A Sea State Bias (SSB) correction has to take into account for exact processing of satellite altimetry data. It has not yet been possible to develop accurate theoretical models of SSB, therefore empirical models are used in practice, calculated individually for each altimeter based on its measurements. For some altimetry missions, the four-parameter model BM4, characterized by a significant wave height and surface wind speed at 10 m height, has proven itself well. The results of estimating the coefficients of BM4 model for two altimetry satellites of the GEO-IK-2 series are presented. It was performed using a least squares method based on the differences in sea surface height (SSH) anomalies, significant wave heights, and surface wind speed at single-satellite crossover points, using different time samples of the initial data: for each calendar year and a total number of valid measurements. Its analysis revealed a significant noise in the SSH anomalies, typical for both Kosmos-2517 and Kosmos-2540 satellite. For the last one, a systematic bias of –22 cm in range estimates and –25 cm in significant wave height estimates was detected, which affected the uncertainty level of the second-order coefficients calculated based on measurements for 2021 and 2022. Despite this, the BM4 models obtained from the different time samples show good mutual consistency for both satellites, and the BM4 model reliably estimates the bias of radio altimetry measurements caused by the state of the sea surface and provides reliable results in a wide range of wind and wave conditions of the World Ocean