Relativity in Communication-Based Time Transfer and Ranging

This paper explores the critical role of relativistic effects in communication-based time transfer and ranging systems, with a focus on their impact in spaceborne applications. As modern systems such as Global Navigation Satellite Systems (GNSS) and deep-space communication networks demand ever-increasing precision, accounting for relativistic effects – including time dilation, propagation delays, and Doppler shifts – becomes essential. We present an analysis of how these effects influence time transfer and ranging in a representative medium Earth orbit (MEO) constellation. Additionally, we introduce new results that bound the error on estimates of the range and desynchronization in the absence of orbital ephemerides, offering improved reliability for systems lacking precise orbital data.