Name
Abstract | ||
|---|---|---|
Slow and significant stochastic variations named “a2-drift” variations are observed in this contribution, which are discovered during the estimation of frequency aging of BeiDou-3 rubidium (Rb) clocks. The magnitude of the variations suffered on BeiDou-3 Rbs is distinctly larger than GPS and appears to exhibit a systematic drift associated with time. The phenomenon is widely ignored and will compromise the long-term (one day and beyond) autonomy of the onboard clock units. Random run frequency modulation (RRFM) noise, which may induce similar variations, can be detected and identified by lag 1 autocorrelation function (lag 1 ACF) and Hadamard deviation. To retrace the origin of the variations, the Hadamard deviations, broadcast clock model parameter
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, and frequency drift of BeiDou-3 Rbs are estimated with reference to GPS. The variations result in long-term fluctuations on the broadcast clock parameters (
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and
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) and arise an increase in the Hadamard deviation when the averaging time is greater than 1e
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s. Furthermore, the simulations of the power-law noises reproduce the variations, and the lag 1 ACF supports that the variations are caused by RRFM. Besides this, many conclusions are also related to this variation. Using two years of multi-global navigation satellite system (GNSS) experiment (MGEX) clock offsets from 2019 to 2021, the following conclusions are drawn: 1) the RRFM emerges as dominant noise and causes a decline in the frequency stability when the averaging time is greater than 1e
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s; 2) the variations on the estimated series of BeiDou-3 Rbs broadcast clock model
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and frequency drift are more visible than those of GPS; 3) when the averaging time is approximately one day, the frequency stability of BeiDou-3 Rbs is similar to that of GPS; however, when the averaging time reaches 1e
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup>
s, the frequency stability of BeiDou-3 Rbs deteriorates because of the RRFM and is nearly ten times lower than that of GPS Rbs; and 4) the GPS Rbs are free from RRFM, but the BeiDou-3 Rbs contain significant features of random-walk frequency modulation (RWFM) and RRFM noise. |
Year | DOI | Venue |
|---|---|---|
2022 | 10.1109/TIM.2022.3187744 | IEEE Transactions on Instrumentation and Measurement |
Keywords | DocType | Volume |
a2-drift variations,BeiDou-3 rubidium (Rb) clocks,frequency aging,frequency drift,random run frequency modulation (RRFM) noise | Journal | 71 |
ISSN | Citations | PageRank |
0018-9456 | 0 | 0.34 |
References | Authors | |
8 | 6 | |
Name | Order | Citations | PageRank |
|---|---|---|---|
| Yuexin Ma | 1 | 0 | 0.34 |
| Chengpan Tang | 2 | 0 | 0.34 |
| Xiaogong Hu | 3 | 3 | 5.61 |
| Zhiqiao Chang | 4 | 0 | 0.34 |
| Yufei Yang | 5 | 0 | 0.34 |
| Jianhua Yang | 6 | 0 | 1.35 |