ETD

• differential corrections
• initial orbit determination
• main-belt asteroids
• near-earth objects
• orbit determination

The determination of celestial body orbits is based on a two-step procedure: the computation of a preliminary orbit and its subsequent refinement through iterative correction methods. This thesis reviews some classical Initial Orbit Determination techniques, such as the Laplace and Gauss methods, highlighting their limitations under unfavorable geometric conditions. In order to address these issues, the admissible region (AR) method is introduced. The refinement of the preliminary orbit is then investigated through differential corrections (DC). Since this method may be affected by numerical instabilities, several improvements aimed at enhancing its robustness are discussed. Finally, a numerical experimentation is presented analyzing the behavior of DC initialized with AR-derived orbits. Tests are performed on datasets of NEOs and main-belt asteroids. The results show that convergence is not always guaranteed and strongly depends on the adopted initialization procedure.