@InProceedings{CarraraKugaBrinCarv:2014:AtDeCo,
               author = "Carrara, Valdemir and Kuga, H{\'e}lio Koiti and Bringhenti, 
                         Philipe Massad and Carvalho, Manoel J. M. de",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)}",
                title = "Attitude Determination, Control and Operating Modes for CONASAT 
                         Cubesats",
            booktitle = "Proceedings...",
                 year = "2014",
         organization = "International Symposium on Space Flight Dynamics, 24. (ISSFD).",
                 note = "{Setores de Atividade: Pesquisa e desenvolvimento 
                         cient{\'{\i}}fico.}",
             keywords = "CubeSat, Attitude determination, Attitude control.",
             abstract = "CONASAT is being designed to gather environmental data like rain 
                         volume, temperature, humidity, air pollution, ocean streams, 
                         environmental hazards, etc. collected and transmitted to satellite 
                         by remote platforms on ground, and to retransmit them to the 
                         mission center. At least two identical satellites shall be 
                         launched, and, together with their antecessors SCD1 and SCD2 (Data 
                         Collecting Satellites 1 and 2, from Brazil) launched in 1993 and 
                         1998, respectively, and still operating, they will provide large 
                         temporal resolution for environmental monitoring. In order to keep 
                         the costs low, CONASAT shall be based on CubeSat technologies. 
                         However, the large power required by onboard data transponder 
                         implied an arrangement of 8 CubeSat units in a single cubic one, 
                         with 230 mm size. All internal subsystems shall be duplicated in 
                         cold redundancy, in order to assure the reliability. In addition, 
                         in order to fulfill the power requirements, the attitude shall be 
                         Earth pointed, since the payload antenna will face to ground. 
                         Although there is no restraint in pointing requirements, a set of 
                         3 off the shelf reaction wheels will be employed so as to assure 
                         satellite maneuverability and attitude stabilization. Attitude 
                         determination will rely in a set of 6 coarse sun sensors (one in 
                         each cube face) and a tri-axes magnetometer. QUEST or TRIAD 
                         algorithm together with Kalman filter will provide onboard 
                         attitude determination and estimation whereas attitude control 
                         will be based on a conventional PID, acting on the reaction 
                         wheels, and three magnetic coils necessary for wheels 
                         de-saturation. Onboard software reliability is assured by 
                         minimizing the number of operating modes. Besides the nominal and 
                         stand-by modes (for Earth pointing and station keeping, 
                         respectively), the attitude acquisition mode and the safe mode for 
                         attitude de-tumbling shall be accomplish by means exclusively of 
                         the magnetometer (Bdot algorithm), course solar sensors and the 
                         torque coils. Since there is no complete attitude determination on 
                         the shadowed part of the orbit, the nominal mode is achieved only 
                         after Kalman filter convergence. This work will present the 
                         attitude control modes for CONASAT, as well as the transition 
                         conditions between modes. The results from the simulated attitude 
                         determination, estimation and control will be addressed, with 
                         focus on the attitude performance for both nominal and safe modes. 
                         This work shall constitute a base line that will guide the 
                         on-board control software development, integration, and 
                         qualification tests.",
  conference-location = "Laurel",
      conference-year = "2014",
                label = "lattes: 0288494962313241 1 CarraraKugaBrin:2014:AtDeCo",
             language = "en",
           targetfile = "ISSFD24_Paper_S1-4_carrara.pdf",
                  url = "https://dnnpro.outer.jhuapl.edu/issfd2014/Agenda.aspx",
        urlaccessdate = "25 abr. 2024"
}