author = "Moraes, Rodolpho Vilhena de and Kuga, H{\'e}lio Koiti and 
                         Kaufmann, Pierre and Kaufmann, P. L. and Pamboukian, S. V. D.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Preliminary satellite orbit determinations using a new system for 
                 year = "2015",
         organization = "IUGG General Assembly, 26.",
             abstract = "The orbit of an artificial satellite carrying a radio signal 
                         transponder is determined using a new geo-referencing system. It 
                         utilizes four ground-based reference stations, synchronized in 
                         time, installed at well known geodetic coordinates, and a repeater 
                         in space. It is based in coded time signal propagation times from 
                         one base to the others bounced back by the transponder. The 
                         process corrects added up time delays due to signal transit times 
                         in the transponder, and for delays due to propagation paths and 
                         electronics at distinct ends. We examine the process application 
                         for an artificial satellite carrying transponder, the orbit of 
                         which we want to determine. The influence of harmonics of high 
                         order and degree due to the non-uniform distribution of the Earths 
                         mass are considered in orbit determination. The paper describes 
                         aspects of the new geo-referencing system and the dynamic modeling 
                         used in the orbit determination system. The specific uncertainties 
                         of measurements arising from this system are properly taken into 
                         account. A simulation performed with four ground bases located in 
                         Brazil and low altitude transponder proved the system concept. 
                         Results show that transponder position accuracies of less than 1 
                         meter are attainable using standard good quality synchronized 
                         clocks. We extend this simulation to orbit determination of 
                         satellites. The major advantages and drawbacks of such system are 
                         discussed. Actual tests on orbiting satellites may be accomplished 
                         using available transponders in existing satellites, as well as in 
                         future cubesat satellites being developed by Brazilian 
  conference-location = "Prague, Czech Republic",
      conference-year = "22 June - 02 July",
        urlaccessdate = "25 nov. 2020"