Identification of the Noise Model in the Time Series of GNSS Stations Coordinates Using Wavelet Analysis

Adrian Kaczmarek,Bernard Kontny

doi:10.3390/rs10101611

Adrian Kaczmarek, Bernard Kontny

Open Access

https://doi.org/10.3390/rs10101611

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Abstract

Analysis of the time series of coordinates is extremely important in geodynamic research. Indeed, the correct interpretation of coordinate changes may facilitate an understanding of the diverse geophysical processes taking place in the earth’s crust. At present, when rigorously processing global navigation satellite system (GNSS) observations, the influence of deformations in the surface of the earth’s crust is not considered. This article presents signal modelling for the influence on the analysis of noise occurring in the time series of GNSS station coordinates. The modelling of coordinate time series was undertaken using the classic least-squares estimation (LSE) method and the inverse continuous wavelet transform (CWT). In order to determine the type of noise character, the coefficient spectral index was used. Analyses have demonstrated that the nature of noise in measurement data does not depend on the signal estimation method. The differences between classic modelling (LSE) of the time series with annual and semiannual oscillation and signal reconstruction are very small ( Δ κ = 0.0 ÷−0.2).

Highlights

Global navigation satellite system (GNSS) coordinate time series have many uses, including estimation of the velocity vectors of measurement stations for geodynamic analysis
The methodology of data elaboration is presented in Sections 2.2.1 and 2.2.2. It contains the basics of signal reconstruction based on coefficients from wavelet analysis—continuous wavelet transform (CWT)—as well as analysis of the type of noise evident in the measurement data
The obtained results show that the method of modelling the time series of GNSS coordinates does not significantly influence the determination of the character of the noise occurring in the measurement data

Summary

Introduction

Global navigation satellite system (GNSS) coordinate time series have many uses, including estimation of the velocity vectors of measurement stations for geodynamic analysis. Changes in coordinate time series, as well as the geodynamic signal, contain geophysical signals that are not eliminated at the stage of observation. These include Atmospheric Pressure Loading (APL), Hydro (Hydrology), and Non-Tidal Ocean Loading (NTOL) [1,2]. In official International Terrestrial Reference Frame (ITRF) solutions, the influence of geophysical factors (APL, Hydro, NTOL) [3] is not taken into account, and only annual and semiannual components are deleted from the data for further geodynamic analyses [4]. Knowledge of the nature of noise informs understanding regarding the uncertainty of the parameters of useful signals, such as geodynamic or geophysical signals, in the time series of coordinate changes. The conclusions were formulated on the basis of a comparison of the results

Input Data

Methods

Analysis of the Character of the Noise

Conclusions