Method for correcting output frequency of CPT (Coherent Population Trapping) atomic clock through GNSS(Global Navigation Satellite System)

Abstract

The invention discloses a method for correcting output frequency of CPT (Coherent Population Trapping) atomic clock through GNSS(Global Navigation Satellite System). The method comprises: generating n time interval signals in a cycle T according to 1PPS signals inputted by the GNSS; measuring the frequencies of output signals of the CPT atomic clock through the time interval signals, wherein one time interval signal measures and records one output signal of the CPT atomic clock; acquiring a plurality of measured values in one cycle T, performing Kalman filtering for the average value of the plurality of measured values so as to serve as an actual output frequency of the CPT atomic clock in the cycle; taking a difference between the actual output frequency and a preset frequency as a frequency deviation of the CPT atomic clock; and correcting the frequency of the output signal of the CPT atomic clock to the preset frequency according to the frequency deviation. The method is capable of inhibiting the drifting of frequencies of CPT atomic clock and improving the accuracy and long-term stability of the CPT atomic clock. The method provided can greatly increase frequency measuring precision when the correction intervals are slightly prolonged.

Description

technical field [0001] The invention belongs to the field of atomic clocks, and in particular relates to a method for correcting the output frequency of a passive coherent population trapping (CPT, CoherentPopulationTrapping) atomic clock by utilizing the second pulse (1PPS, 1 pulsepersecond) output by a Global Navigation Satellite System (GNSS, GlobalNavigationSatelliteSystem) receiver. The CPT atomic clock realized by this method can obtain high frequency stability and accuracy, and can suppress frequency drift. Background technique [0002] CPT atomic clock is a new type of atomic clock. It has the characteristics of small size, low power consumption, and fast start-up speed. It can be widely used in positioning, navigation, communication base stations, and precision timing. [0003] The CPT atomic clock uses microwaves to modulate the Vertical Cavity Surface Emitting Laser (VCSEL, Vertical Cavity Surface Emitting Laser) to generate frequency-modulated polychromatic light...

AI Technical Summary

Problems solved by technology

[0005] Due to the process of signal propagation from the satellite to the receiver and the noise introduced by the receiver itself, the 1PPS signal clock sequence obtained through the GNSS receiver has jitter relative to the sequence corresponding to the international standard time, and the jitter of 1PPS output by the ordinary receiver is as high as 10— 100ns, if you directly use 1PPS as a standard time source to measure the frequency of the CPT atomic clock output signal, it will bring a large frequency measurement error

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