Phase clock performance improvement for a system embedded with GNSS receiver

An apparatus connected to a fixed Global Navigation Satellite System (GNSS) receiver system, the apparatus comprising circuitry configured to:

• store a phase history of the GNSS receiver output,
• determine an expected value of phase of the GNSS receiver output based on the phase history,
• adjust the GNSS receiver output utilizing the expected value of phase, responsive to a variation and/or degradation of the GNSS receiver output;
• and
• provide a holdover output from a physical frequency reference and with a phase adjusted based on the expected value of phase, responsive to the degradation being a loss of the GNSS receiver output, wherein the physical frequency reference is any of a Synchronous Ethernet (SyncE) Interface, a Precision Time Protocol (PTP) interface, a Building Integrated Timing Supply (BITS) clock, and an unbalanced physical interface having a frequency of about 10 Mhz and that is traceable to a Primary Reference Clock (PRC).

A fixed Global Navigation Satellite System (GNSS) receiver system comprising:

• a GNSS receiver connected to an antenna and configured to output a pulse at a predetermined frequency;
• circuitry configured to
• store a phase history of the output of the GNSS receiver,
• determine an expected value of phase of the GNSS receiver based on the phase history,
• responsive to a variation and/or degradation of the GNSS receiver output, adjust the output of the GNSS receiver utilizing the expected value of phase;
• and
• a physical frequency reference that is traceable to a Primary Reference Clock (PRC) or higher accuracy frequency clock, wherein the circuitry is configured to
• responsive to the variation of the GNSS receiver output, utilize the phase history to re-generate the GNSS receiver output for performance enhancement, and
• responsive to the degradation being a loss of the GNSS receiver output, utilize a holdover output from the physical frequency reference and with a phase adjusted based on the expected value of phase.