Frequency Stability of GPS NAVSTAR Block I and Block II On-Orbit Clocks
NAVAL RESEARCH LAB WASHINGTON DC
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Analysts of the frequency stability of on-orbit NAVSTAR clocks is performed by the Naval Research Laboratory. This work was sponsored by the GPS Joint Program Ofice. The frequency stability is presented for sample times of one day to 30 days. Composite frequency-stability profiles are presented for the Block I and Block II NAVSTAR clocks. Several NAVSTAR cesium clocks show frequency stabilities of a few parts in 10 to the 14th power for long sample times. Time-domain noise-process analysis shows the dominant noise type to be white frequeng noise for sample times of one to ten days. The non-stationary stochastic behavior of one of the cesium clocks, illustrated by its frequency-stability history, shows that the frequency stability is not always time-invariant.
- Navigation and Guidance