Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis.

Xin Wang,Bo Li,Luxi Huang,Fan Zhao,Xinyu Luo,Xiaohui Li,Ping Feng

doi:10.3390/s21041216

Abstract

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

Highlights

Owing to the close relationship between the Earth and the Sun, the solar eclipse observation has been very important for the study of astrophysics and the sun itself [1], and for the study of radio transmissions that rely on the ionosphere as a propagation and reflection medium [2,3]
This study evaluates the influence of the annular eclipse on the field strength of low-frequency time-code signals; analyzes the influence mechanism to improve the stability and continuity of the low-frequency time-code time service system; and meets the application requirements of time-frequency signals in space science, aerospace, and other related technology industries
Owing to the fact that the low-frequency time-code signal relies on sky waves for long-distance transmission, if we want to explore the influence of the solar eclipse on the low-frequency time-code signal, the signal reflection point needs to be set in the ring eclipse zone, the signal from the Shangqiu station of the low-frequency time code is reflected on the test point by a certain point on the eclipse zone

Summary

Introduction

Owing to the close relationship between the Earth and the Sun, the solar eclipse observation has been very important for the study of astrophysics and the sun itself [1], and for the study of radio transmissions that rely on the ionosphere as a propagation and reflection medium [2,3]. The magnitude of eclipse increases and the solar zenith distance decreases from the initial depletion to the eclipse. These two factors affect the change of solar radiation flux to the ionosphere [17]

Methods

Findings

Discussion

Conclusion