Relativistic corrections for inter-satellite frequency transfer

Abstract

Highly accurate time and frequency synchronization is crucial for navigation. Constant improvements in clock technology enable more precise systems. This in turn places stricter demands on coordination and dissemination of timescales. This paper is motivated by an interest in evaluating future concepts for GNSS (Global Navigation Satellite System) constellations. Within the field of space-based time and frequency transfer, inter-satellite links are of high interest for GNSS clock synchronization. In addition to synchronizing clocks, these links can improve orbit determination through precise ranging. Transmissions resolve time and frequency information (i.e. clock offsets and drifts) by modeling satellite orbit effects and propagation delays. In order to fully capitalize on the stability of next-generation space clocks, relativistic corrections must be described to a high level of precision and satellite positions must be accurately known.