Research on variation test of atomic time based on pulsar observation

Abstract

Pulsar time (PT) has high long-term stability, and its establishment process is completely different from that of atomic time (AT). Therefore, pulsar-based time scale can be used as an independent test for the fluctuation of atomic time scale. In this paper, the test results of the fluctuation of atomic time using pulsar time are presented in combination with the real clock difference data. In order to test the fluctuation of atomic time, the timing model parameters of four pulsars are used to simulate the pulse times of arrival (TOAs) data with TT(BIPM19) as the reference, and then the reference time is changed from TT(BIPM19) to TT(TAI). Based on this, the classical weighted average algorithm and the Wiener filtering algorithm are used to extract the variations of the atomic time relative to the pulsar time. The test results obtained by the two methods are compared, and it shows that the Wiener filtering algorithm is better than the weighted average algorithm for the extraction of the fluctuation of the atomic time. The wavelet threshold denoising method is added to the clock difference signal extracted by the Wiener filtering algorithm to deduct the high-frequency noise. After denoising, PT is closer to TT(BIPM19), which further improves the ability of PT to detect the fluctuation of AT. For the TOA measurement accuracy of 100 ns, the difference between PT and TT(BIPM19) can be kept roughly within 40 ns. This paper studies the method of further improving the accuracy of PT under the premise of given TOA measurement accuracy, which is of great significance for the next step to use PT for more effective application of time keeping.