author = "Romero, Alessandro Gerlinger and Souza, Luiz Carlos Gadelha de and 
                         Chagas, Ronan Arraes Jardim",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Application of the SDRE technique in the satellite attitude and 
                         orbit control system with nonlinear dynamics",
            booktitle = "Proceedings...",
                 year = "2018",
         organization = "International Conference on Space Operations, 15. (SpaceOps)",
            publisher = "American Institute of Aeronautics and Astronautics",
             abstract = "The satellite attitude and orbit control subsystem (AOCS) can be 
                         designed with success by linear control theory if the satellite 
                         has slow angular motions and small attitude maneuver. However, for 
                         large and fast maneuvers, the linearized models are not able to 
                         represent all the perturbations due to the effects of the 
                         nonlinear terms present in the dynamics and in the actuators 
                         (e.g., saturation) which can damage the systems performance. 
                         Therefore, in such cases, it is expected that nonlinear control 
                         techniques yield better performance than the linear control 
                         techniques, improving the AOCS pointing accuracy without requiring 
                         a new set of sensors and actuators. One candidate technique for 
                         the design of AOCS control law under a large and fast maneuver is 
                         the State-Dependent Riccati Equation (SDRE). SDRE provides an 
                         effective algorithm for synthesizing nonlinear feedback control by 
                         allowing nonlinearities in the system states while offering great 
                         design flexibility through state-dependent weighting matrices. The 
                         Brazilian National Institute for Space Research (INPE, in 
                         Portuguese) was demanded by the Brazilian government to build 
                         remote-sensing satellites, such as the Amazonia-1 mission. In such 
                         missions, the AOCS must stabilize the satellite in three-axes so 
                         that the optical payload can point to the desired target. 
                         Currently, the control laws of AOCS are designed and analyzed 
                         using linear control techniques in commercial software. In this 
                         paper, we discuss whether the application of the SDRE technique in 
                         the AOCS design can yield gains in the missions developed by INPE. 
                         Moreover, we report a proof of concept of an open-source satellite 
                         simulator built to analyze control laws based on SDRE. This 
                         satellite simulator is implemented in Java using Hipparchus 
                         (linear algebra library; which was extended in order to support 
                         the SDRE technique) and Orekit (flight dynamics framework).",
  conference-location = "Marseille, France",
      conference-year = "28 may - 01 june",
                  doi = "10.2514/6.2018-2536",
                  url = "http://dx.doi.org/10.2514/6.2018-2536",
                 isbn = "9781624105623",
                label = "lattes: 5964335207790589 3 RomeroSouzChag:2018:ApSDTe",
             language = "en",
           targetfile = "romero_application.pdf",
                  url = "http://www.spaceops2018.org",
        urlaccessdate = "17 jan. 2021"