摘要：Abstract
The spatial correlation between different stations
for individual components in the regional GNSS networks
seems to be significant. The mismodelling in satellite
orbits, the Earth orientation parameters (EOP), largescale
atmospheric effects or satellite antenna phase centre
corrections can all cause the regionally correlated errors.
This kind of GPS time series errors are referred to as
common mode errors (CMEs). They are usually estimated
with the regional spatial filtering, such as the "stacking".
In this paper, we show the stacking approach for the set
of ASG-EUPOS permanent stations, assuming that spatial
distribution of the CME is uniform over the whole region
of Poland (more than 600 km extent). The ASG-EUPOS
is a multifunctional precise positioning system based on
the reference network designed for Poland. We used a 5-
year span time series (2008-2012) of daily solutions in the
ITRF2008 from Bernese 5.0 processed by the Military University
of Technology EPN Local Analysis Centre (MUT
LAC). At the beginning of our analyses concerning spatial
dependencies, the correlation coefficients between each
pair of the stations in the GNSS network were calculated.
This analysis shows that spatio-temporal behaviour of the
GPS-derived time series is not purely random, but there is
the evident uniform spatial response. In order to quantify
the influence of filtering using CME, the norms L1 and L2
were determined. The values of these norms were calculated
for the North, East and Up components twice: before
performing the filtration and after stacking. The observed
reduction of the L1 and L2 norms was up to 30% depending
on the dimension of the network. However, the question
how to define an optimal size of CME-analysed subnetwork
remains unanswered in this research, due to the
fact that our network is not extended enough.
关键词：KeywordsGPSASG-EUPOS spatio-temporal filtering
common mode error (CME)stacking
