author = "Silva, William Reis and Garcia, Roberta V. and Kuga, H{\'e}lio 
                         Koiti and Zanardi, Maria Cecilia",
          affiliation = "{Instituto Tecnologico de Aeron{\'a}utica (ITA)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade Federal do ABC 
                title = "Spacecraft attitude estimation using unscented kalman filters, 
                         regularized particle filter and extended H filter",
              journal = "Advances in the Astronautical Sciences",
                 year = "2018",
               volume = "162",
                pages = "1195--1214",
             abstract = "In this work, the attitude determination and the gyros drift 
                         estimation will be described for nonlinear systems using the 
                         Extended Kalman Filter (EKF), Extended H Filter (EHF), 
                         Second-Order Extended H Filter (SOEHF), Unscented Kalman Filter 
                         (UKF) and Regularized Particle Filter (RPF). An analysis of these 
                         estimation methods will be done, verifying which of them present 
                         better precision in such study. The attitude model is described by 
                         quaternions and the attitude sensors available are two DSS 
                         (Digital Sun Sensors), two IRES (Infrared Earth Sensor), and one 
                         triad of mechanical gyros. The application uses the simulated 
                         measurement data for orbit and attitude of the CBERS-2 (China 
                         Brazil Earth Resources Satellite) which has polar sun-synchronous 
                         orbit with an altitude of 778km, making about 14 revolutions per 
                         day. In this orbit, the satellite crosses the equator line always 
                         at the same local time, around 10:30 am. This dynamics allows the 
                         same conditions of solar illumination to be obtained during the 
                         acquisition of images. The simulated measurements of the CBERS-2 
                         were provided by the inhouse package PROPAT, a Satellite Attitude 
                         and Orbit Toolbox for Matlab. The results in this work show that 
                         one can reach accuracies in attitude determination within the 
                         prescribed requirements, besides providing estimates of the gyro 
                         drifts which can be further used to enhance the gyro error 
                 issn = "0065-3438.",
             language = "en",
           targetfile = "silva_artigo.pdf",
        urlaccessdate = "23 jan. 2021"