S Zohrabzadeh Bozorgi - PhD student, Aerospace Eng. Department, Amirkabir University of Technology,
A Naghash - Associate professor, Aerospace Eng. Department, Amirkabir University of Technology

This paper proposes a hybrid constellation comprising GEO and LEO satellites as the space segment of a regional satellite navigation service to be used by users within Iranian territory. At first, typical satellite constellation patterns suitable for local services and currently operational systems are introduced. Then the background of proposed constellations for local navigation in Iran in the literature is reviewed. It is concluded that traditionally, regional navigation constellations are designed based on satellites in GEO, IGSO and eccentric IGSO orbits. New approaches in leveraging LEO constellations for satellite navigation along with the advantages of such patterns for global and local coverage are presented. The capability of navigation with LEO satellites in decreasing the convergence time of PPP due to the rapid change of satellites geometry is described. Then, a new approach based on a hybrid constellation comprising GEO and LEO satellites is proposed for local satellite navigation and the economical and operational advantages of such combination is expressed. It is shown that such hybrid constellation can be economically profitable. Different viable options for the proposed hybrid constellation are discussed and the optimization problem to reach the desired combination is defined. The proposed hybrid concept can be addressed by satellite constellation planners

Satellite Navigation, Regional Navigation, Hybrid Constellation