Geodesy and Space situational awareness: How geodetic ground infrastructure enables navigation

Geodesy, the science of measuring and understanding the Earth's shape, orientation, and gravitational field, plays a crucial role in the field of spacecraft navigation and space situational awareness. As the number of spacecraft constellations increase, the integration of geodetic techniques with navigation systems has become essential to ensure precise trajectory planning, positioning, and orbit determination. This presentation explores the fundamental links between geodesy and space navigation and space situational awareness, examining how geodetic infrastructure is key to positioning in space and on earth. Key areas of focus include the use of geodetic reference frames, global navigation systems (like GPS) and Earth orientation parameters. Two examples using Very long base Interferometry and Satellite Laser ranging will be presented to explain the contribution of global geodetic observatory systems to the parameters required for navigation and their role in determining accurate satellite orbits and in tracking variations in the Earth’s center of mass. We will discuss how these techniques contribute to the definition of the reference frames required for navigation and to the increasing demands on accuracy for positioning. Additionally, we will explain how these techniques offer unique data required for navigation and their strengths. By unveiling the not-so evident link between terrestrial geodetic infrastructure and satellite operations, we aim to highlight why this infrastructure is essential for space navigation, collision avoidance and to improve our ability to provide more accurate positioning standards. The presentation concludes by explaining why Global Navigation Satellite Systems like GPS aren’t sufficient to define these parameters and the challenges posed by an increasing number of satellites in space, signal interference and aging ground infrastructure.