Permanent Network Research Articles

Q–Str2–Models: A software in PyQGIS to obtain Stress–Strain models from GNSS geodynamic velocities

Q–Str2–Models is an opensource application developed in Python (PyQGIS) and integrated into QGIS that provides us with several tools for creating Stress–Strain models in geodynamically active areas, from the calculation of the horizontal velocities of many points from a temporal or permanent GNSS network. This software generates the results of the maximum geodetic deformation, shear deformation, rotation and dilatation of the points, which are later translated into graphic products; heatmaps, displacement vectors and Stress–Strain tensors. In this article we show the results of the application of Q–Str2–Models for the analysis of 65 GNSS stations of SPINA (South of the Iberian Peninsula and North Africa) network to know the geodynamic behavior of the Andalusian region and its surroundings.

Recyclable Solid–Solid Phase Change Materials with Excellent Reprocessing Properties Based on Dynamic Disulfide Bonds

Phase change materials (PCMs) with energy-saving and sustainable energy potential are widely available for energy storage technologies. At present, chemical cross-linking is often constructed to form solid–solid phase change materials (SSPCMs) to avoid leakage during the phase change process, but its permanent cross-linked network cannot be reprocessed, resulting in nonrecyclable materials with very high environmental impact. Herein, we prepare a series of poly(ethylene glycol) (PEG)-containing reprocessed solid–solid phase change materials (RSSPCMs) based on dynamic disulfide bonds, which were in the solid state even at high temperatures. These RSSPCMs had high latent heat with a maximum value of 100.2 J/g, which exhibited remarkable thermal storage capacity in addition to excellent solar-thermal conversion capacity. Interestingly, the introduction of dynamic disulfide bonds in the molecular structure provided RSSPCMs with excellent self-healing properties and recyclability. Broken RSSPCM samples could heal under thermal-induced and infrared radiation-induced reprocessing. Importantly, the chemical structure, crystallization behavior, and phase transition ability of RSSPCMs could also remain unchanged after multiple recycling. Designing RSSPCMs based on dynamic disulfide bonds is important for achieving the efficient utilization of solar energy and environmental protection.

Extracellular matrix mimicking dynamic interpenetrating network hydrogel for skin tissue engineering

Tissue engineering scaffolds with tunable viscoelasticity and adaptability for cell behavior and fate regulation are highly desired. Here a dynamic interpenetrating polymer network (IPN) hydrogel was fabricated via photopolymerization and oxidation of methacryloyl gelatin (GelMA) and hyaluronic acid (HASH). The permanent GelMA network formed by CC bonds provides stable support for cells while the dynamic HASH network formed by disulfide bonds provides an adaptable microenvironment for cell growth. The proposed IPN hydrogel exhibits extensive and tunable porosity, swelling, degradation, and mechanical properties. Remarkably, the dynamic IPN hydrogel mimics the viscoelasticity and adaptability of the extracellular matrix (ECM), which can regulate cellular behaviors such as morphogenesis, alignment, proliferation, migration while offering resistance to cell mediated shrinkage and enzymatic digestion, maintaining the structural integrity of the scaffold. Our results suggest that dynamic IPN 3/7 (HASH/GelMA) hydrogels had more similar physical properties to human skin and were more favorable for human skin fibroblasts (HSF) and human immortalized keratinocytes (HaCaT) growth. Moreover, bilayer tissue-engineered skin prepared using the dynamic IPN hydrogel exhibited satisfactory mechanical stability, dermal-epidermal stratification, matrix secretion, structural differentiation, and barrier functions. In addition, the bilayer tissue-engineered skin can significantly promote healing of full-thickness skin defects through accelerated wound re-epithelialization, collagen deposition, and angiogenesis, without causing non-specific or specific immune rejection. This work based on the novel dynamic IPN hydrogel with biomimetic viscoelasticity and adaptability demonstrates the promising application in tissue engineering.

All talk, and (no) action? Collaborative implementation of the renewable energy transition in two frontrunner municipalities in Denmark

Municipalities play a key role in transitioning to a climate neutral and 100% renewable energy system. Although alternative energy system models, feasibility analyses and strategic energy plans are being developed, municipalities lack the know-how, funding, authority or political demand needed to implement the plans. Collaborative design and implementation of energy plans through cross-sectoral networks could help overcome some of these barriers. However, there is little empirical evidence of how collaboration could be sustained during implementation and how it could be institutionalised in a permanent governance network, resulting in a perception that collaboration is ‘all talk and no action’. This paper presents a comparative case study of two municipal energy governance networks in Denmark with two different institutional designs: the municipality-led Energi2020 network in Ringkøbing-Skjern and the public–private network administrative organisation ProjectZero in Sønderborg, in which the municipality participates as a partner. It was found that institutional design influences the ability to mobilise private funding, the access to municipal resources and the degree of political control. In addition, it has important consequences for the design and evaluation of energy plans, their outputs and outcomes and the accountability for their implementation. As a result, Ringkøbing-Skjern has been more successful in renewable energy installation, while Sønderborg has been more successful in improving industrial energy efficiency and sector coupling. It is concluded that ultimately, the two approaches need to be combined to develop a smart energy system that relies on 100% renewable energy, energy efficiency and sector coupling.

Guidance, Navigation, and Control of AUVs for Permanent Underwater Optical Networks

Ocean exploration is in its infancy with more than 80% of the oceans still unexplored. Contrary to space exploration, electromagnetic waves have seldom been used underwater because of their heavy absorption by seawater. In this article, we present guidance, navigation, and control systems to steer autonomous underwater vehicles (AUVs) such that a permanent optical network can be set up between the deep sea and the surface. The challenge is to guarantee that there is consistently a path through the AUV network to relay the signal for an unlimited time despite the finite battery's lifetime of the AUVs. To achieve this, the guidance system combines a decentralized model predictive control (D-MPC) with graph theory to compute the trajectory of each agent relaying the optical signal as well as of redundant agents forming local leader–follower formations with each relay acting as leader of its own subfleet. The D-MPC solves a constrained optimization problem where the communication and collision avoidance constraints are formulated to enable two successive leaders and one of their followers to remain within optical range and thus allowing to immediately re-route the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ad hoc</i> network if a leader fails to relay the signal. Its combination with graph theory allows to change the dynamic topology of the swarm, with additional agents diving from a charging station, such that the network can relay the optical signal for an unlimited time.

Dynamic growth model for oak stands in Moscow, Russia

The most objective information about the state of Moscow’s forests is provided by long-term observation data on permanent trial plots. Such data makes it possible to identify changes in forest stands under the influence of recreationists, environmental pollution, and climate change. Long-term observational data are particularly valuable in modeling forest stand growth and productivity. The goal of the study is to develop a dynamic model of the growth of oak stands in Moscow based on long-term observation data. The modelling data were obtained from 7 plots of the permanent sample plot network established by the Forest Experimental Station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. There are a total of 42 inventories and the number of inventories per plot range from 3 to 9. Inventories were carried out between 1927 and 2009. We used three initial state variables for prediction, as in many studies. Taking into account the peculiarities of the inventory of forest stands in Russia, the mean height, quadratic mean diameter and number of trees per hectare were used as initial variables. All obtained models meet the requirements for forest inventory in Russia in terms of error values of stand attributes. The model in this study provides a simple and reliable system for predicting the growth and yield of Moscow oak stands.

Implications on crustal structure from the South Finland Coastal (SOFIC) deep seismic sounding profile

We present results from a deep seismic sounding (DSS) experiment carried out along the southern coast of Finland in summer 2015. Data used in the survey derived from industrial blasts recorded by temporary project stations and permanent network stations. The western 220 km part of the 450 km long Southern Finland Coastal (SOFIC) profile runs along the Uusimaa belt (UB) in the 1.7–1.9 Ga Southern Finland subprovince (SFS) of the Svecofennian domain, while the 170 km part in the east crosses the 1.62–1.65 Ga Wiborg rapakivi batholith (WRB). The farthest 60 km cross a geologically diverse area consisting of supracrustal rocks and granitoids of the Saimaa area (SA), an eastern extension of the SFS. Our results show that the Moho boundary depth varies significantly, from ca. 52–54 km below UB to 40–45 km below WRB. All three crustal layers (upper, middle, and lower) have their maximum depth in the contact zone between UB and the WRB. Below WRB, a lower crust with Vp ~6.7–6.9 km/s is observed. High velocity lower crust was observed below UB (Vp ~7.2 km/s) and possibly below SA (Vp ~7.35 km/s). The modelling was based on ray tracing, using the extrapolation of seismic wave arrival times with the help of travel times predicted from a one-dimensional velocity model. The resulting two-dimensional velocity model partly relies on data from the intersecting DSS profiles and supports previous observations of the lithospheric structure of southeastern Fennoscandia.

Impact of BeiDou Observations on the Accuracy of Multi-GNSS PPP in a Function of Observing Session Duration within Europe—Analysis Based on Open-Source Software GAMP

This study aims to verify whether the open-source software may provide Precise Point Positioning (PPP) with high accuracy. In this way, we address a question on the potential usability of open-source software for PPP analysis. On 31 July 2020, the full constellation of BeiDou satellites (SV) was announced. Over the European area, however, the number of visible BeiDou SVs is significantly smaller than in Asian-Pacific regions. Additionally, the system is in a modernization process, which may result in difficulties in utilizing its full potential. Ten days of multi-GNSS data were processed using the open-source software GAMP to determine how the accuracy of a derived three-dimensional PPP coordinates depends on observation session length and satellite systems used. The time series of position components of selected EUREF Permanent Network (EPN) stations generated from sub-daily (30 min and longer) solutions were analyzed. The obtained results prove that adding BeiDou observations, even in the case of using an incomplete constellation, leads to visible improvements, which can be observed both in the reduction of differences between estimated and true coordinates, as well as in the reduction of the standard deviation (SD). Improved accuracy caused by adding BeiDou data is especially noticeable for short observation sessions (in the range of 0.5 to 2.0 h) and in the case of a joint solution with GLONASS or Galileo observations. Finally, the open-source software GAMP proved to be a useful tool for multi-GNSS data processing and analysis.

Role of breaking physical crosslinks on safeguarding polymer networks

Polymer networks that are crosslinked jointly by covalent bonds and reversible physical bindings usually offer superior mechanical strength and toughness compared to their permanently crosslinked counterparts. By introducing short oligomers as stickers that bind physically to different polymer chains, the resulting polymer networks show a unique feature of dissipating stretching-induced energy, which is absent in permanent networks. We show that large sized clusters of physical crosslinks in a transient network break into smaller pieces when the transient network is stretched at strain rates sufficiently high that the transiently crosslinked structure is not given enough time to relax. After deducting the part of the stress that is generated solely by a thermal motion-driven structural readjustment of the transient network, the stress enhancement arising from a stretching-enforced breakup of physical crosslinks is quantitatively verified, demonstrating the sacrificial role played by these physical crosslinks in safeguarding the unrelaxed structure.

CORS Networks, Aspects of Business Models in Europe and the Region

&amp;lt;p&amp;gt;The paper describes the functioning of CORS permanent networks in the world. Special attention has been paid to the EPN network and the regional CORS networks in Bosnia and Herzegovina, Serbia, Montenegro, and Croatia. BiHPOS: SRPOS and FBiHPOS, AGROS, CROPOS, and MONTEPOS were analyzed from the aspect of mutual data exchange with the aim of achieving better location accuracy and removing deficiencies in the network geometries. Due to their individual development, as well as mutually concluded agreements on data exchange, measurements obtained using GNSS today have a wide range of applications, such as maritime communication, aviation, engineering work, earth monitoring, and many more. Also, the points of the region included in the EPN network with the aim of exchanging data at the European level are shown.&amp;lt;/p&amp;gt;

Effects of Noise Pollution on Residents Living in Birzebbuga and the Introduction of Effective Mitigation Measures

There exists a direct influence of noise pollution on people's quality of life which can lead to several short and long-term health consequences. This paper presents the first phase of a mixed-method study conducted to understand the effects of noise pollution on residents living in Birzebbuga, Malta, followed by a second phase project completed in 2021. A questionnaire was completed by 477 inhabitants to obtain demographic information and data about noise pollution, its influence on residents' activities, and noise source discomfort. The study utilised the International Commission on the Biological Effects of Noise's five-scale technique to quantify noise irritation. The survey took place between February and May 2021. Data reported that in 98% of the participants noise pollution is a problem. 61.6% of respondents reported noise annoyance as the main category of pollution on health and well-being, followed by sleeping disorders and fatigue, stress, nervousness, loss of concentration, headaches and reduced ability to work. Given high levels of noise and the effects on the quality of life of residents, this study concludes that noise reduction regulations are a must, and a permanent sound monitoring network within the district of Birzebbuga is a crucial component for an effective low-noise implementation plan.

An updated view of the Italian seismicity from probabilistic location in 3D velocity models: The 1981–2018 Italian catalog of absolute earthquake locations (CLASS)

We have built a complete catalog of three-dimensional (3D) hypocenter locations of earthquakes recorded in Italy from 1981 to 2018. Our catalog includes more than 420,000 events relocated by inverting a newly integrated dataset of ∼5.0 million P and ∼ 3.5 million S wave arrival times recorded by the Italian National Seismic Network and other permanent seismological networks operating in Italy. Available magnitudes are associated with earthquake locations from the most recent datasets and bulletins of Italian seismicity. Earthquakes are located in an updated 3D tomographic model of Italy obtained by including the Moho discontinuity and the seismic velocities of the Ionian subduction zone. We used a probabilistic, non-linear earthquake location code which provides complete information of the hypocenter solution uncertainties. Quality estimators of earthquake locations are analyzed a posteriori with an original criterion for a quantitative classification of the results, allowing users to select seismic events belonging to consistent quality classes and giving a more controlled image of the Italian instrumental seismicity for tectonic and geodynamical studies. The resulting catalog gives a new, coherent view of the spatial and temporal distribution of Italian seismicity. By selecting well constrained located events we construct the new Italian Crustal Seismogenic Layer (CSL) with a good spatial resolution, allowing us to show a comparison between seismogenic thicknesses and Moho geometry distribution. We finally present some examples of seismicity distribution in selected areas of Italy at regional and local scale relating the relocated events of our catalog with available multidisciplinary information from geology, geochemistry, geodynamical models, and historical seismicity.

Load transfer between permanent and dynamic networks due to stress gradients in nonlinear viscoelastic hydrogels

Relaxation experiments are performed on single edge notch tension (SENT) and T shape specimens consisting of different variations of polyampholyte (PA) hydrogels. These specimens share a common feature of containing regions of high and low stress/strain. This feature enables us to probe the load transfer mechanisms between permanent and dynamic networks of different strengths. This load transfer mechanism is connected to viscoelastic behavior. PA gels are nonlinear viscoelastic, with time-dependent behavior controlled by the breaking and reforming of ionic bonds in the dynamic network. In contrast to the prediction of linear viscoelastic theory, the displacement and strain fields during stress relaxation are not fixed but change with time in a complex way depending on the strength of the dynamic bonds and the observation time window. These experimental results are explained by a nonlinear viscoelastic model. Additional physical insights are gained by appealing to the nonlinear rheology of dynamic bonds or stickers. Our result shows that load transfer between networks can be controlled by modifying the strength of dynamic bonds.

Possibility of using the DInSAR method in the development of vertical crustal movements with Sentinel-1 data

AbstractWe investigate the possibility of using Differential interferometric synthetic aperture radar (DInSAR) to develop models of vertical crustal movements (VCMs). We determined VCM using the DInSAR method in the locations of four Polish GNSS stations: Borowa Góra, Borowiec, Lamkówko, and Józefosław. They are included in the International GNSS service and EUREF permanent GNSS networks. All Sentinel-1A and 1B satellite data were from 2020, and the time intervals of the created interferograms are 12 days, 24 days, and 336 days for each of the orbits: ascending and descending. We verified the calculated results of VCM based on GNSS data recorded by individual stations. We developed reference data with the precise point positioning (PPP) method. We confronted them with the Nevada Geodetic Laboratory service. The GNSS data covered larger time intervals than the synthetic aperture radar (SAR) data. To calculate daily positions with the PPP method we used GipsyX software. The obtained results of the directions of displacement are convergent between SAR and GNSS data. The values differ from each other, both between the types of orbits and GNSS data. The obtained results allow us to assume that SAR data developed using the DInSAR method may provide additional support in the development of VCM models in the Polish area, but they cannot be the only source of such results.

New CNN-based tool to discriminate anthropogenic from natural low magnitude seismic events

SUMMARY With the deployment of high quality and dense permanent seismic networks over the last 15 yr comes a dramatic increase of data to process. In order to lower the threshold value of magnitudes in a catalogue as much as possible, the issue of discrimination between natural and anthropogenic events is becoming increasingly important. To achieve this discrimination, we propose the use of a convolutional neural network (CNN) trained from spectrograms. We built a database of labelled events detected in metropolitan France between 2020 and 2021 and trained a CNN with three-component 60 s spectrograms ranging frequencies from 1 to 50 Hz. By applying our trained model on independent French data, we reach an accuracy of 98.2 per cent. In order to show the versatility of the approach, this trained model is also applied on different geographical areas, a post-seismic campaign from NW France and data from Utah, and reaches an accuracy of 100.0 and 96.7 per cent, respectively. These tests tend to hypothesize that some features due to explosions compared to earthquakes are widely shared in different geographical places. In a first approach, we propose that it can be due to a contrast in the energy balance between natural and anthopogenic events. Earthquake seismic energies seem to be more continuous as a function of frequency (vertical bands features in a spectrogram) and conversely for explosions (horizontal strips).

Offshore ground motion characteristics on the horizontal PGA, spectral acceleration, frequency content and significant duration from the 2021 Mw 7.1 and 2022 Mw 7.4 offshore earthquakes near the Japan Trench area

The two large offshore earthquakes that occurred in Japan's eastern Fukushima region on February 13, 2021, Mw 7.1 and March 17, 2022, Mw 7.4 are the two largest offshore earthquakes recorded by the large-scale permanent ocean-bottom seismograph network (S-net). The two earthquakes are both subduction slab earthquakes and caused great damage to onshore structures. The offshore ground motions from the S-net within a fault distance of 300 km were selected to investigate the characteristics of the strong offshore motions. The onshore ground motions are also selected from the K-net to compare the differences in offshore and onshore ground motions. These onshore and offshore datasets were used to calculate the representative ground motion parameters: the peak ground acceleration (PGA), spectral acceleration, frequency content and significant duration of the earthquakes. Here we present the comparison of the offshore and onshore ground motions in amplitude, duration and frequency content, as well as the applicability of the representative onshore ground motion model (GMM) to the offshore region. Additionally, we provide the spatial contours of the parameters used in this study and the residual analysis to examine the effects of the water depth, sedimentary layer and station deployment method on the offshore ground motions. We found that the PGA and spectral accelerations of unburied seafloor stations are larger than those of buried stations, and the attenuation rate observed from the spatial contours between the offshore and onshore regions is different, which shows the necessity of proposing a new prediction model for the PGA and spectral accelerations in offshore regions. The significant duration of offshore ground motions is consistent with the onshore prediction model of significant duration in the subduction zone but is on average greater than those of onshore ground motions. For the frequency content, there is no prediction model for subduction zones at present. The frequency-content parameters of offshore ground motions are relatively consistent with the frequency-content model for greater depths. On the whole, the complex environment at the ocean bottom has the most significant influence on the spectral accelerations over long periods and has some influence on the duration and frequency content, but the overall difference is smaller than the PGA and spectral accelerations.

Investigating temporal and spatial patterns in the stochastic component of ZTD time series over Europe

The EUREF Permanent GNSS Network (EPN) provides a unique atmospheric dataset over Europe in the form of Zenith Total Delay (ZTD) time series. These ZTD time series are estimated independently by different analysis centers, but a combined solution is also provided. Previous studies showed that changes in the processing strategy do not affect trends and seasonal amplitudes. However, its effect on the temporal and spatial variations of the stochastic component of ZTD time series has not yet been investigated. This study analyses the temporal and spatial correlations of the ZTD residuals obtained from four different datasets: one solution provided by ASI (Agenzia Spaziale Italiana Centro di Geodesia Spaziale, Italy), two solutions provided by GOP (Geodetic Observatory Pecny, Czech Republic), and one combined solution resulting from the EPN’s second reprocessing campaign. We find that the ZTD residuals obtained from the three individual solutions can be modeled using a first-order autoregressive stochastic process, which is less significant and must be completed by an additional white noise process in the combined solution. Although the combination procedure changes the temporal correlation in the ZTD residuals, it neither affects its spatial correlation structure nor its time-variability, for which an annual modulation is observed for stations up to 1,000 km apart. The main spatial patterns in the ZTD residuals also remain identical. Finally, we compare two GOP solutions, one of which only differs in the modeling of non-tidal atmospheric loading at the observation level, and conclude that its modeling has a negligible effect on ZTD values.

Quasi-4-dimension ionospheric modeling and its application in PPP

Ionospheric delay modeling is not only important for Global Navigation Satellite System (GNSS) based space weather study and monitoring, but also an efficient tool to speed up the convergence time of Precise Point Positioning (PPP). In this study, a novel model, denoted as Quasi-4-Dimension Ionospheric Modeling (Q4DIM) is proposed for wide-area high precision ionospheric delay correction. In Q4DIM, the Line Of Sight (LOS) ionospheric delays from a GNSS station network are divided into different clusters according to not only the location of latitude and longitude, but also satellite elevation and azimuth. Both Global Ionosphere Map (GIM) and Slant Ionospheric Delay (SID) models that are traditionally used for wide-area and regional ionospheric delay modeling, respectively, can be regarded as the special cases of Q4DIM by defining proper grids in latitude, longitude, elevation, and azimuth. Thus, Q4DIM presents a resilient model that is capable for both wide-area coverage and high precision. Four different sets of clusters are defined to illustrate the properties of Q4DIM based on 200 EUREF Permanent Network (EPN) stations. The results indicate that Q4DIM is compatible with the GIM products. Moreover, it is proved that by inducting the elevation and azimuth angle dependent residuals, the precision of the 2-dimensional GIM-like model, i.e., Q4DIM 2-Dimensional (Q4DIM-2D), is improved from around 1.5 Total Electron Content Units (TECU) to better than 0.5 TECU. In addition, treating Q4DIM as a 4-dimensional matrix in latitude, longitude, elevation, and azimuth, whose sparsity is less than 5%, can result in its feasibility in a bandwidth-sensitive applications, e.g., satellite-based Precising Point Positioning Real-Time Kinematic (PPP-RTK) service. Finally, the advantages of Q4DIM in PPP over the 2-dimensional models are demonstrated with the one month's data from 30 EPN stations in both high solar activity year 2014 and low solar activity year 2020.

Injectable, Self-Healing and Multiple Responsive Histamine Modified Hyaluronic Acid Hydrogels with Potentialities in Drug Delivery, Antibacterial and Tissue Engineering.

Hydrogels are 3D network structures composed of physically or chemically crosslinked, hydrophilic molecules. Compared with conventional hydrogels with static and permanent network structures, injectable and responsive hydrogels generated from dynamic networks, have attracted increasing attention from various disciplines due to their wide-ranging applications in tissue engineering, drug delivery, soft robotics, etc. Herein, an injectable self-healing and multiple-responsive hyaluronic acid (HA)- histamine (His)/metal hydrogel is developed by modifying His onto HA and the subsequent, dynamic coordination between imidazole and metal ions. The pH-responsive and mechanical behaviors exhibited by the HA-His/metal hydrogels are tunable with the kinds and the concentrations of metal ions. The HA-His/Zr4+ hydrogels demonstrate a moldable capability at a neutral pH and a multi-stimulus-responsive capability when exposed to a weak alkaline environment and hyaluronidase, which inhibits bacterial growth and biofilm formation. Biocompatibilities and accelerated wound healing are demonstrated in vitro and in vivo and are thoroughly investigated and well characterized. The HA-His/Zr4+ hydrogel has great potential in various biomedical applications, such as pH- and hyaluronidase-responsive sustained release, antibacterial, and implantable materials for tissue engineering.

Offsets in the EPN station position time series resulting from antenna/radome changes: PCC type-dependent model analyses

The EUREF Permanent Network (EPN) currently consists of more than 300 evenly distributed continuously operating Global Navigation Satellite System (GNSS) reference stations. As a result of the continuous modernization of GNSS systems, the equipment of reference stations is subject to changes and upgrades. Changes relating to GNSS receiver antenna replacement are considered the main reason for discontinuities noticed in station position time series. It is assumed that resulting offsets are primarily caused by changes in carrier phase multipath effects after antenna replacement. However, the observed position shifts may also indicate the deficiency in the antenna phase center corrections (PCC) models. In this paper, we identified and interpreted the coordinate shifts caused by antenna/radome changes at selected EPN stations. The main objective was to investigate the correlation between the offset occurrence and PCC model type (type mean, individual robot-derived, individual chamber-derived) as well as multipath changes after antenna replacement. For the study, GNSS data from 12 EPN stations covering the years 2017–2019 were analyzed. The results proved that the antenna replacement is critical in the context of station coordinates stability and, in most cases, results in visible shifts in the position component time series. For GPS-only solutions, the most stable results were achieved using robot-derived individual PCC models. On the other hand, in the case of GPS + Galileo processing, the most stable results were obtained using chamber-derived individual PCC models. Furthermore, discontinuities due to the antenna change were noticed in the position time series in 75% of GPS + Galileo solutions. On the other hand, multipath changes arising as the result of antenna replacement were responsible, depending on solution type, for 21–42% of variations in the coordinates.