Advances in Satellite Ranging Methods Towards Precise Orbit Determination

Accuracy in the satellite positioning is crucial for maintaining integrity and functionality, especially in safety-critical services of communication, navigation, and imaging applications. Perturbations in space affect the accuracy of satellite orbits. This paper discusses the satellite ranging methods, viz. ground-based tracking, onboard GNSS receivers, and inter-satellite links for satellite orbit determination. Accuracies achieved using the individual and combination of ranging methods have been analysed in this paper for the satellites in different orbits. The study reveals that the satellites in low earth orbit increasingly depend on onboard GNSS receivers supported by ISL for better accuracy and to reduce dependency on the ground-based tracking. Satellites in the medium-earth orbits rely predominantly on one-way CDMA ranging, supported by ISL to improve autonomy and accuracy. Satellites in geo-synchronous orbits and beyond utilise either passive or ground-based RF ranging. Advances in the Space Service Volume simulations in effectively utilising the GNSS applications in space are discussed. The paper analyses the accuracy levels and improvements in using hybrid ranging techniques across all orbits to optimize satellite positioning, emphasising the importance of continuity and autonomy in satellite operations.