<h2>AAS 97-165</h2>
<h2>ATTITUDE DETERMINATION FOR SPIN STABILIZED SATELLITES FROM  GPS INTERFEROMETRY                                                                   </h2>
<h4> R. V. F. Lopes, S. M. Fabri and L. Do. O. Ferreira, INPE-Instituto Nacional de  Pesquisas Espaciais, Brazil                                                              </h4>
<h2> Abstract </h2>
 The aim of this work is to present a complete GPS-based attitude determination  procedure for spin stabilized satellites.  Starting with interferometric  observations of GPS carrier phase, the attitude vector, phase angle and spin rate  are estimated by the extended Kalman filter.  Numerical results from digital  simulation are presented, as well as some real data from an experiment on the  ground.  Real satellite application is also envisaged under the scope of the  Brazilian space program.