Characteristics of seasonal variations and noises of the daily double-difference and PPP solutions

Abstract

Long term GNSS observations provided by networks of the continuously operating reference stations (CORS) allow for determination of the global and local tectonic plate movements and seasonal variations. In recent years, PPP (Precise Point Positioning) technique has become increasingly popular and most likely in the future will replace relative positioning with CORS stations. In this paper, we discuss the difference of the velocity and seasonal component estimates of 25 Latvian CORS stations on the basis of daily PPP solutions from the Nevada Geodetic Laboratory and double-difference solutions from the Institute of Geodesy and Geoinformatics of the University of Latvia. Time series of each coordinate component for 9-year time period were determined by the usage of the Tsview software and seasonal existence of linear, annual, semi-annual factors and their uncertainties were determined. Breaks (e. g., antenna and receiver changes) were also taken into account. We then assessed the noise characteristics of these time series with the use of overlapping Hadamard variance (OHVAR). The result shows that OHVAR is computationally cheap, and the dominating power-law noise, including flicker and random walk. However Hadamard deviation of the PPP and double-difference solutions scatters differently for a whole year averaging time due to the different GNSS data strategies.

Analysis of the Current Dynamic of the Jalisco Block, Mexico through GNSS Observations

“…The Tsview tool, by Thomas Herring, United States of America, complemented the GAMIT/GLOB-K software for GPS time series analysis [16]. It filtered out atypical data and outliers using the 3-sigma criterion [17][18][19]. Corrections were made for hardware/firmware changes and earthquakeinduced landslides.…”

Geodesy, Cartography and Aerial Photography

“…Long-term time series of GNSS stations have been widely used to monitor Earth's movements (for example, plate tectonics, sea level changes, pole motion studies, etc.). First of all, long-term GNSS observations from the permanent and reference stations allow us to determine the global and local movement of tectonic plates, as well as to identify seasonal fluctuations [Maciuk, et al, 2021]. The velocities of tectonic plates obtained from coordinate time series are regularly used as input data for geophysical models.…”