Observability, ensemble averaging and GPS time

Obtaining time from an ensemble of clocks with a Kalman filter when the system is not observable is examined. Particular attention is given to the Global Positioning System (GPS) master control station (MCS) Kalman filter and the ramifications of estimating ensemble time under conditions of unobservability are explored. The effect of one proposed workaround to problems caused by unobservability is addressed.<
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