Abstract
The Global Navigation Satellite System (GNSS) and GNSS receivers can be used to measure the time-frequency errors of receiver clocks so as to evaluate their frequency stability. The calculation of receiver clock error by single point positioning (SPP) is not highly accurate, resulting in the limited evaluation of clock frequency stability. Therefore, this study proposes a precision point positioning (PPP) evaluation method. In this method, the receiver is driven by an external clock to be evaluated, and the receiver clock error calculated by PPP is used as the measured clock phase error to calculate the Allan variance. The frequency stability of three clocks with different grades (temperature compensated crystal oscillator [TCXO], oven controlled crystal oscillator [OCXO], and rubidium clock) are evaluated with the PPP evaluation method. The PPP evaluation method can evaluate the frequency stabilities of TCXO and OCXO for an average interval of more than 1 s, and the evaluation error of OCXO is less than 1.3 × 10 -11 . As for the rubidium clock, its frequency stability can be evaluated by the PPP evaluation method for an average interval of more than 66 s, and the error is less than 2 × 10 -13 . In general, the PPP evaluation method involves simple operations, achieves high accuracy, and is easily popularized.
Highlights
Frequency stability is an important performance evaluation indicator for clocks
A NovAtel board card is used as a Global Navigation Satellite System (GNSS) receiver, RTKLIB software is used as the precision point positioning (PPP) and single point positioning (SPP) calculation tool, STABLE32 software [21] is utilized as the Allan variance calculation tool, a hydrogen atomic clock with high frequency stability serves as the reference frequency source for the electronic evaluation method, and a 3120A phase noise and Allan variance tester (3120A tester) are used as measuring equipment for the electronic evaluation method
Expressed by the overlapping Allan deviation, the overall noise of the PPP evaluation method at a 1 s average interval is at the level of 10−12, and it is lower than 2 × 10−14 at 10000 s average intervals
Summary
Frequency stability is an important performance evaluation indicator for clocks. It is characterized by the power spectral density in the frequency domain and characterized by Allan variance in the time domain [1]. In the PPP evaluation method, the GNSS receiver driven by the frequency of the clock to be measured is used to obtain the positioning observation.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
