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Wyświetlanie 1-3 z 3
Tytuł:
Progression of clock DBD changes over time
Autorzy:
Maciuk, Kamil
Varna, Inese
Kudrys, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/27311748.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
GPS
satellite
clock
jump
outlier
DBD
reference clock
Opis:
Day-boundary discontinuity (DBD) is an effect present in precise GNSS satellite orbit and clock products originating from the method used for orbit and clock determination. The non-Gaussian measurement noise and data processing in 24 h batches are responsible for DBDs. In the case of the clock product, DBD is a time jump in the boundary epochs of two adjacent batches of processed data and its magnitude might reach a couple of ns. This article presents the four GNSS (Global Navigation Satellite System) systems DBD analysis in terms of change over an 8 year period. For each of 118 satellites available in this period, the yearly value of DBD was subject to analysis including standard deviation and frequency of outliers. Results show that the smallest DBDs appear in the GPS system, the biggest - for the BeiDou space segment. Moreover, the phenomenon of changes in DBDs over time is clearly seen at the beginning of the analysed period when the magnitude and number of the DBDs were larger than for current, newest clock products.
Źródło:
Metrology and Measurement Systems; 2023, 30, 3; 499--505
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient frequency jumps detection algorithm for atomic clock comparisons
Autorzy:
Marszalec, Michał
Lusawa, Marzenna
Osuch, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1848989.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
time interval
phasetime
frequency jump
ensemble time scale
atomic clock
Opis:
In this paper a new method of frequency jumps detection in data from atomic clock comparisons is proposed. The presented approach is based on histogram analysis for different time intervals averaging phasetime data recorded over a certain period of time. Our method allows identification of multiple frequency jumps for long data series as well to almost real-time jump detection in combination with advanced filtering. Several methods of preliminary data processing have been tested (simple averaging, moving average and Vondrak filtration), to achieve flexibility in adjusting the algorithm parameters for current needs which is the key to its use in determining ensemble time scale or to control systems of physical time scales, such as UTC(PL). The best results have been achieved with the Vondrak filter.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 107-121
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the GMDH neural network data preparation method on UTC(PL) correction prediction results
Autorzy:
Miczulski, W.
Sobolewski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/221698.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
GMDH neural network
national timescale
atomic clock
time series analysis
Opis:
The article presents results of the influence of the GMDH (Group Method of Data Handling) neural network input data preparation method on the results of predicting corrections for the Polish timescale UTC(PL). Prediction of corrections was carried out using two methods, time series analysis and regression. As appropriate to these methods, the input data was prepared based on two time series, ts1 and ts2. The implemented research concerned the designation of the prediction errors on certain days of the forecast and the influence of the quantity of data on the prediction error. The obtained results indicate that in the case of the GMDH neural network the best quality of forecasting for UTC(PL) can be obtained using the time-series analysis method. The prediction errors obtained did not exceed the value of š 8 ns, which confirms the possibility of maintaining the Polish timescale at a high level of compliance with the UTC.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 123-132
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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