Rendezvous and Proximity Operations (RPO) with non-cooperative targets represent a key challenge in space missions, as they require accurate and reliable navigation systems. In particular, a critical aspect is the estimation of the relative position and attitude of a non-cooperative target satellite with respect to the chaser during the final approach phase, which is crucial in terms of safety and autonomy. Traditional navigation methods relying on cooperative sensors or pre-installed markers are not applicable in such scenarios, motivating the adoption of vision-based navigation techniques. This thesis focuses on algorithms for target satellite pose estimation in RPO missions. Two different approaches were identified and developed.