Network Time Protocol (NTP) is a standard protocol for synchronising the time of client computers on the Internet and computer networks. The protocol operates in a hierarchical manner, each level or stratum serving the next level in the hierarchy. At the highest level of the hierarchical structure is a stratum 1 NTP server that synchronise's to an external time and frequency reference.
The Rubidium atomic clock, the simplest and most compact of all, use a glass cell of rubidium gas that changes its absorption of light at the optical rubidium frequency when the surrounding microwave frequency is just right.
Rubidium oscillators operate at 6834 MHz, the resonance frequency of the Rubidium atom. Rubidium synchronised oscillators have a much higher quality factor (Q) but are relatively expensive. However, manufacturing and design advances mean Rubidium Oscillators are constantly becoming smaller and less expensive. Rubidium based NTP servers can provide a highly stable timing reference but are still relatively expensive.
Ankabut operates a Rubidium oscillators that is synchronised t the GPS system, while not directly acceaasable by Ankabut’s member Ankabut does offer a Stratum 2 Proxy NTP services, that allows both accuracy and security of the original timing source