Frequency synchronization Using GPS Carrier Phase

We propose a new scheme of frequency synchronization using GPS carrier phase based on fuzzy and PD controller. Using carrier phase double-difference with respect to receivers and time, the remote OCXO clock can be steered to obtain an excellent performance through weighting least square estimation and appropriate controllers. The accuracy of the remote clock can be improved from about to about a few parts in for averaging times of one day over a 30-meter baseline. Moreover, the zero-baseline tests with the common high-performance cesium clock show that our system has a frequency stability of a few parts in for averaging times of one day. Experimental results show that our system is sound and cost-effective in many applications, such as the PRS (Primary Reference Source) of telecommunication network, the frequency traceable to the national standard for frequency calibration laboratory, instrument calibrations, etc. Combining the rubidium atomic oscillator, low-cost GPS engines (with carrier phase option) and other data links for the long baseline applications is currently under investigation.

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