Abstract: Thousands of meteorological observations collected from the meteorological services around the world and satellites data are used for operating systems for Numerical Weather Prediction (NWP) employing different techniques of data assimilation. The Center for Weather Forecast and Climatic Studies of the National Institute for Space Research (CPTEC-INPE) is implementing the global analysis system called PSAS (Phisycalspace Statistical Analysis System) (GPSAS) to generate initial conditions for its global model CPTEC/COLA. The data assimilation process requests measures of the real state of the atmosphere, these measurements are the meteorological observations received from Global Telecommunications System (GTS)/National Institute ofMeteorology (INMET), from satellite data, and alternatively from the National Environmental Satellite Data and Information Service (NESDIS) and from Environment Satellite Division (DSA/CPTEC), for satellite date. The analysis system gives an indispensable adjust of the model state of weather forecast in agreement with the observations, once there are not observations for all the points of the domain of the models. These observations are prepared in agreement with the requirements of the assimilation system. In this paper methods used for selection and adaptation of satellite observat ions ATOVS will be presented, as well as a general view of its space distribution and the impact in analysis between ATOVS from GTS and from INMET/DSA.