scholarly journals “Noise characteristics in Zenith Total Delay from homogeneously reprocessed GPS time series” by Anna Klos

2017 ◽  
Author(s):  
Anonymous
Keyword(s):  
Time Series ◽  
Total Delay ◽  
Zenith Total Delay ◽  
Noise Characteristics ◽  
Gps Time Series

scholarly journals Noise characteristics in Zenith Total Delay from homogeneously reprocessed GPS time series

2016 ◽  
Author(s):  
Anna Klos ◽  
Addisu Hunegnaw ◽  
Felix Norman Teferle ◽  
Kibrom Ebuy Abraha ◽  
Furqan Ahmed ◽  
...  
Keyword(s):  
Time Series ◽  
White Noise ◽  
Autoregressive Process ◽  
Noise Model ◽  
Total Delay ◽  
Tropical Zone ◽  
Climate Zones ◽  
Zenith Total Delay ◽  
Noise Characteristics ◽  
Gps Time Series

Abstract. Zenith Total Delay (ZTD) time series, derived from the re-processing of Global Positioning System (GPS) data, provide valuable information for the evaluation of global atmospheric reanalysis products such as ERA-Interim. Identifying the correct noise characteristics in the ZTD time series is an important step to assess the "true" magnitude of ZTD trend uncertainties. The ZTD residual time series for 1995–2015 are generated from our homogeneously re-processed and homogenized GPS time series from over 700 globally distributed stations classified into five major climate zones. The annual peak of ZTD data ranges between 10 and 150 mm with the smallest values for the polar and Alpine zone. The amplitudes of daily curve fall between 0 and 12 mm with the greatest variations for the dry zone. The autoregressive process of fourth order plus white noise model were found to be optimal for ZTD series. The tropical zone has the largest amplitude of autoregressive noise (9.59 mm) and the greatest amplitudes of white noise (13.00 mm). All climate zones have similar median coefficients of AR(1) (0.80 ± 0.05) with a minimum for polar and Alpine, which has the highest coefficients of AR(2) (0.27 ± 0.01) and AR(3) (0.11 ± 0.01) and clearly different from the other zones considered. We show that 53 of 120 examined trends became insignificant, when the optimum noise model was employed, compared to 11 insignificant trends for pure white noise. The uncertainty of the ZTD trends may be underestimated by a factor of 3 to 12 compared to the white noise only assumption.

scholarly journals Supplementary material to "Noise characteristics in Zenith Total Delay from homogeneously reprocessed GPS time series"

2016 ◽  
Author(s):  
Anna Klos ◽  
Addisu Hunegnaw ◽  
Felix Norman Teferle ◽  
Kibrom Ebuy Abraha ◽  
Furqan Ahmed ◽  
...  
Keyword(s):  
Time Series ◽  
Total Delay ◽  
Zenith Total Delay ◽  
Noise Characteristics ◽  
Supplementary Material ◽  
Gps Time Series

scholarly journals GPS Time Series Analysis from Aboa the Finnish Antarctic Research Station

2018 ◽  
Vol 10 (12) ◽  
pp. 1937 ◽  
Author(s):  
Constantin-Octavian Andrei ◽  
Sonja Lahtinen ◽  
Maaria Nordman ◽  
Jyri Näränen ◽  
Hannu Koivula ◽  
...  
Keyword(s):  
Time Series ◽  
Flicker Noise ◽  
Research Station ◽  
Long Time Series ◽  
Noise Characteristics ◽  
Gps Time Series Analysis ◽  
Long Time ◽  
Antarctic Research ◽  
Rms Error ◽  
Gps Time Series

Continuous Global Positioning System (GPS) observations have been logged at the Finnish Antarctic research station (Aboa) since February 2003. The station is located in Dronning Maud Land, East Antarctica. Almost 5000 daily observation files have been archived based on yearly scientific expeditions. These files have not been fully analysed until now. This study reports for the first time on the consistent and homogeneous data processing and analysis of the 15-year long time series. Daily coordinates are obtained using Precise Point Positioning (PPP) processing based on two approaches. The first approach is based on the Kalman filter and uses the RTKLIB open source library to produce daily solutions by unconventionally running the filter in the forward and backward direction. The second approach uses APPS web service and is based on GIPSY scientific processing engine. The two approaches show an excellent agreement with less than 3 mm rms error horizontally and 6 mm rms error vertically. The derived position time series is analysed in terms of trend, periodicity and noise characteristics. The noise of the time series was found to be power-law noise model with spectral index closer to flicker noise. In addition, several periodic signals were found at 5, 14, 183 and 362 days. Furthermore, most of the horizontal movement was found to be in the North direction at a rate of 11.23 ± 0.09 mm/y, whereas the rate in the East direction was estimated to be 1.46 ± 0.05 mm/y. Lastly, the 15-year long time series revealed a movement upwards at a rate of 0.79 ± 0.35 mm/y. Despite being an unattended station, Aboa provides one of the most continuous and longest GPS time series in Antarctica. Therefore, we believe that this research increases the awareness of local geophysical phenomena in a less reported area of the Antarctic continent.

scholarly journals Noise characteristics of GPS time series and their influence on velocity uncertainties

2019 ◽  
Vol 128 (6) ◽  
Author(s):  
Jagat Dwipendra Ray ◽  
M Sithartha Muthu Vijayan ◽  
Ashok Kumar
Keyword(s):  
Time Series ◽  
Noise Characteristics ◽  
Gps Time Series

A global grid model for the correction of the vertical zenith total delay based on a sliding window algorithm

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Liangke Huang ◽  
Ge Zhu ◽  
Lilong Liu ◽  
Hua Chen ◽  
Weiping Jiang
Keyword(s):  
Sliding Window ◽  
Total Delay ◽  
Grid Model ◽  
Zenith Total Delay ◽  
Global Grid

scholarly journals GPS measurements on pre-, co- and post-seismic surface deformation at first multi-parametric geophysical observatory, Ghuttu in Garhwal Himalaya, India

2020 ◽  
Vol 10 (1) ◽  
pp. 136-144
Author(s):  
P.K. Gautam ◽  
S. Rajesh ◽  
N. Kumar ◽  
C.P. Dabral
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Translational Motion ◽  
Anomalous Behavior ◽  
Deformation Pattern ◽  
Local Earthquakes ◽  
Position Time Series ◽  
Continuous Gps ◽  
Gps Time Series ◽  
Gps Station

Abstract We investigate the surface deformation pattern of GPS station at MPGO Ghuttu (GHUT) to find out the cause of anomalous behavior in the continuous GPS time series. Seven years (2007-2013) of GPS data has been analyzed using GAMIT/GLOBK software and generated the daily position time series. The horizontal translational motion at GHUT is 43.7 ± 1 mm/yr at an angle of 41°± 3° towards NE, while for the IGS station at LHAZ, the motion is 49.4 ±1 mm/yr at 18 ± 2.5° towards NEE. The estimated velocity at GHUT station with respect to IISC is 12 ± 1 mm/yr towards SW. Besides, we have also examined anomalous changes in the time series of GHUT before, after and during the occurrences of local earthquakes by considering the empirical strain radius; such that, a possible relationship between the strain radius and the occurrences of earthquakes have been explored. We considered seven local earthquakes on the basis of Dobrovolsky strain radius condition having magnitude from 4.5 to 5.7, which occurred from 2007 to 2011. Results show irrespective of the station strain radius, pre-seismic surface deformational anomalies are observed roughly 70 to 80 days before the occurrence of a Moderate or higher magnitude events. This has been observed for the cases of those events originated from the Uttarakashi and the Chamoli seismic zones in the Garhwal and Kumaun Himalaya. Occurrences of short (< 100 days) and long (two years) inter-seismic events in the Garhwal region plausibly regulating and diffusing the regional strain accumulation.

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