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Detecting offsets in GPS time series: first results from the detection of offsets in GPS experiment
Citation
Gazeaux, J and Williams, S and King, M and Bos, M and Dach, R and Deo, M and Moore, AW and Ostini, L and Petrie, E and Roggero, M and Teferle, FN and Olivares, G and Webb, FH, Detecting offsets in GPS time series: first results from the detection of offsets in GPS experiment, Journal of Geophysical Research B: Solid Earth, 118, (5) pp. 2397-2407. ISSN 0148-0227 (2013) [Refereed Article]
Copyright Statement
Copyright 2013 American Geophysical Union
Abstract
The accuracy of Global Positioning System (GPS) time series is degraded by the presence of offsets. To assess the effectiveness of methods that detect and remove these offsets, we designed and managed the Detection of Offsets in GPS Experiment. We simulated time series that mimicked realistic GPS data consisting of a velocity component, offsets, white and flicker noises (1/f spectrum noises) composed in an additive model. The data set was made available to the GPS analysis community without revealing the offsets, and several groups conducted blind tests with a range of detection approaches. The results show that, at present, manual methods (where offsets are hand picked) almost always give better results than automated or semi-automated methods (two automated methods give quite similar velocity bias as the best manual solutions). For instance, the fifth percentile range (5% to 95%) in velocity bias for automated approaches is equal to 4.2 mm/year (most commonly ±0.4 mm/yr from the truth), whereas it is equal to 1.8 mm/yr for the manual solutions (most commonly 0.2 mm/yr from the truth). The magnitude of offsets detectable by manual solutions is smaller than for automated solutions, with the smallest detectable offset for the best manual and automatic solutions equal to 5 mm and 8 mm, respectively. Assuming the simulated time series noise levels are representative of real GPS time series, robust geophysical interpretation of individual site velocities lower than 0.2-0.4 mm/yr is therefore certainly not robust, although a limit of nearer 1 mm/yr would be a more conservative choice. Further work to improve offset detection in GPS coordinates time series is required before we can routinely interpret sub-mm/yr velocities for single GPS stations.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | GPS, time series, offset detection |
| Research Division: | Earth Sciences |
| Research Group: | Geophysics |
| Research Field: | Geodesy |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the earth sciences |
| UTAS Author: | King, M (Professor Matt King) |
| ID Code: | 88541 |
| Year Published: | 2013 |
| Funding Support: | Australian Research Council (FT110100207) |
| Web of Science® Times Cited: | 118 |
| Deposited By: | Geography and Environmental Studies |
| Deposited On: | 2014-02-06 |
| Last Modified: | 2017-10-30 |
| Downloads: | 0 |
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