Optimization of a LEO‐PNT Constellation: Design Considerations and Open Challenges

ABSTRACT As the satellite launch and manufacturing costs have become affordable, the industrial and academic interest in low‐Earth orbit (LEO) satellites has increased in recent years. With this interest, the concept of LEO‐based positioning, navigation, and timing (LEO‐PNT) has also gained popularity as a complementary and/or standalone system in addition to the already existing Global Navigation Satellite Systems (GNSS). This article proposes a LEO constellation optimization methodology from the perspective of a LEO‐PNT design, identifies and discusses the state‐of‐art of the LEO satellite constellation optimization approaches, introduces relevant performance‐ and feasibility‐related metrics and parameters, and addresses key concepts and trade‐offs that must be considered for any LEO‐PNT constellation design. In addition, a case study for a LEO‐PNT constellation optimization is presented, where we showcase the discussed trade‐offs. We present optimization results obtained with the adaptive weighting algorithm “ADaW” applied to the Pareto‐optimization algorithm nondominated sorting genetic algorithm III (“NSGA‐III”). A detailed performance analysis is done for six relevant scenarios with varying receiver location properties, namely, by considering indoor/outdoor, rural/urban and line of sight/non–line of sight (NLOS) cases.