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1

Integrated precipitable water from GPS observations and CIMEL sunphotometer measurements at CGO Belsk

Kruczyk M., Liwosz T., Pietruczuk A.

Reports on Geodesy and Geoinformatics

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2017

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Vol. 103

46--65

EN

This paper describes results of integrated precipitable water co-located measurements from two techniques: GPS solution and CIMEL-318 sun-photometer. Integrated Precipitable Water (IPW) is an important meteorological parameter and is derived from GPS tropospheric solutions for GPS station at Central Geophysical Observatory (CGO), Polish Academy of Sciences (PAS), Belsk and compared with sunphotometer (CIMEL-318 device by Cimel Electronique) data provided by Aerosol Robotic Network (AERONET). Two dedicated and independent GPS solutions: network solution in the sub-network of European Permanent Network (EPN) and precise point positioning solution have been made to obtain tropospheric delays. The quality of dedicated tropospheric solutions has been verified by comparison with EPN tropospheric combined product. Several IPW comparisons and analyses revealed systematic difference between techniques (difference RMS is over 1 mm). IPW bias changes with season: annual close to 1 mm IPW (and semi-annual term also present). IPW bias is a function of atmospheric temperature. Probable cause of this systematic deficiency in solar photometry as IPW retrieval technique is a change of optical filter characteristics in CIMEL.

2

Geodetic and geodynamic studies at Department of Geodesy and Geodetic Astronomy WUT

Brzeziński A., Barlik M., Andrasik E., Izdebski W., Kruczyk M., Liwosz T., Olszak T., Pachuta A., Pieniak M., Próchniewicz D., Rajner M., Szpunar R., Tercjak M., Walo J.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 100

165--200

EN

The article presents current issues and research work conducted in the Department of Geodesy and Geodetic Astronomy at the Faculty of Geodesy and Cartography at Warsaw University of Technology. It contains the most important directions of research in the fields of physical geodesy, satellite measurement techniques, GNSS meteorology, geodynamic studies, electronic measurement techniques and terrain information systems.

3

Long series of GNSS Integrated Precipitable Water as a climate change indicator

Kruczyk M.

Reports on Geodesy and Geoinformatics

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2015

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Vol. 99

1--18

EN

This paper investigates information potential contained in tropospheric delay product for selected International GNSS Service (IGS) stations in climatologic research. Long time series of daily averaged Integrated Precipitable Water (IPW) can serve as climate indicator. The seasonal model of IPW change has been adjusted to the multi-year series (by the least square method). Author applied two modes: sinusoidal and composite (two or more oscillations). Even simple sinusoidal seasonal model (of daily IPW values series) clearly represents diversity of world climates. Residuals in periods from 10 up to 17 years are searched for some long-term IPW trend – self-evident climate change indicator. Results are ambiguous: for some stations or periods IPW trends are quite clear, the following years (or the other station) not visible. Method of fitting linear trend to IPW series does not influence considerably the value of linear trend. The results are mostly influenced by series length, completeness and data (e.g. meteorological) quality. The longer and more homogenous IPW series, the better chance to estimate the magnitude of climatologic IPW changes.

4

Integrated Precipitable Water Vapour measurements at Polish Polar Station Hornsund from GPS observations verified by aerological techniques

Kruczyk M., Liwosz T.

Reports on Geodesy and Geoinformatics

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2015

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Vol. 98

1--17

EN

We present results of the comparison of integrated precipitable water measurements from GPS solution and aerological techniques: CIMEL-318 sun-photometer and radiosoundings (RAOB). Integrated Precipitable Water (IPW) - important meteorological parameter is derived from GPS tropospheric solutions by known procedure for GPS station at Polish Polar Station, Hornsund (Svalbard). The relation between 2 m temperature and the mean temperature of atmosphere above, used to convert from wet part of tropospheric delay (ZWD) to IPW, has been derived using local radiosonde data at Ny Alesund. Sunphotometer data have been provided by AERONET. Quality of dedicated tropospheric solutions has been verified by comparison with EPN tropospheric combined product. Several IPW comparisons and analyses lead to determination of systematic difference between techniques: GPS IPW and sunphotometer data (not present in case of RAOBs). IPW measured by CIMEL is on average 5% bigger (0.5 mm) than IPW from GPS. This bias changes seasonally and is a function of atmospheric temperature what signals some systematic deficiencies in solar photometry as IPW retrieval technique. CIMEL IPW show some temperature dependent bias also in relation to radiosoundings.

5

Comparison of techniques for Integrated Precipitable Water measurement in the polar region

Kruczyk M.

Geoinformation Issues

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2015

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Vol. 7, no. 1(7)

15--27

EN

Tropospheric delay estimates (tropospheric product) for selected International GNSS Service (IGS) and EUREF Permanent Network (EPN) stations made it possible to asses two areological techniques in the polar region (mainly in Greenland). Integrated Precipitable Water (IPW) – important meteorological parameter is derived from GPS tropospheric solutions by a known procedure for GPS stations. To convert from the wet part of tropospheric delay (ZWD) to IPW, the relation between 2 m temperature and the so-called mean temperature of the atmosphere above was derived using local radiosonde data for nearby GPS stations. Sunphotometer data were provided by AERONET (NASA AErosol RObotic NETwork). IPW comparisons lead to the determination of a systematic difference between the techniques of GPS IPW and sunphotometer data (not present in the case of RAOBs). IPW measured by sunphotometer CIMEL (Cimel Electronique) is several percent smaller than IPW from GPS (both IGS and EPN solution). The bias changes seasonally and is a function of atmospheric temperature. It signals some systematic deficiencies in solar photometry as the IPW retrieval technique. CIMEL IPW shows some temperature dependent bias also in relation to radiosoundings.

PL

Rozwiązania troposferyczne IGS i EPN zostały wykorzystane do przetestowania dwu technik pomiarów aerologicznych dla stacji GNSS w regionie polarnym (Grenlandia). Parametr meteorologiczny jakim jest scałkowana zawartość pary wodnej (IPW) został pozyskany za pomocą standardowej procedury opisanej w literaturze. Do przeliczania IPW z wilgotnej części opóźnienia opracowano lokalny model temperatury średniej (zależność linowa względem temperatury na wysokości 2 metrów nad powierzchnią ziemi) wyznaczony z radiosondowań prowadzonych w sąsiedztwie stacji GNSS. Pomiary fotometryczne udostępnia sieć pomiarów aerozoli AERONET działająca pod egidą NASA. Porównania kilkuletnich szeregów IPW wykazują systematyczne różnice między IPW z GNSS a fotometrem słonecznym (ale nie radiosondażem). IPW z fotometru jest nie tylko średnio kilka procent mniejsza niż z GNSS ale różnica ta zmienia się wraz z porami roku i temperaturą (co jest szczególnie widoczne w warunkach polarnych). To wykazuje pewien istotny problem z fotometrią słoneczną jako techniką pomiarów kolumnowej pary wodnej. Fotometr wykazuje systematyczną różnicę IPW (zależną od temperatury atmosferycznej) także w stosunku do wyników radiosondażu.

6

Integrated precipitable water from GNSS as a climate parameter

Kruczyk M.

Geoinformation Issues

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2014

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Vol. 6, no. 1(6)

21--35

EN

Tropospheric delay estimates (tropospheric product) on selected International GNSS Service (IGS) and EUREF Permanent Network (EPN) stations exhibit large information potential for meteorology and climate research. Long time series of integrated precipitable water (IPW) averaged hourly, daily and monthly can serve as climate indicators. As IPW is mostly influenced by global circulation, not surface processes, correlations of IPW with basic meteorological surface parameters have been analysed. Even more revealing are changes in correlation coefficients calculated for montly periods for different regions. Simple charts of IPW/temperature which can be treated as climatologic diagrams were investigated. Some of these charts have been analysed with some climatologic insight. This form of presenting IPW statistics reveals the variability of sensonal IPW values. IPW clearly represents the diversity of world climates and is a valuable meteorological and climatologic parameter.

PL

Obliczane opóźnienia troposferyczne (czyli tak zwany produkt troposferyczny) są standardowym efektem działalności międzynarodowych służb: Międzynarodowej Służby GNSS (IGS) i Permanentnej Sieci EUREF (EPN) dostarczają cennych informacji wykorzystywanych w meteorologii i klimatologii. Długie serie rozwiązań scałkowanej (kolumnowej) zawartości pary wodnej (IPW) po odpowiednim uśrednieniu w przedziałach godzinnym, dobowym i miesięcznym mogą służyć jako indykatory lokalnego klimatu. Zmienność IPW jest zdeterminowana w pierwszym rzędzie przez cyrkulację globalną atmosfery, co potwierdzają wyniki analiz korelacji IPW z podstawowymi parametrami meteorologicznymi rejestrowanymi na stacjach GNSS. Szczególnie interesujące są zmiany współczynnika korelacji obliczanego w okresach miesięcznych. Ujawniają one charakterystyczne cechy lokalnej cyrkulacji w różnych regionach. W pracy zaproponowano użycie pewnego rodzaju diagramu klimatologicznego (IPW/temperatura w odcinkach miesięcznych, uśrednione w okresie wieloletnim). Wybrane wykresy tego typu zostały przeanalizowane pod kątem cech klimatu. Poza mniej lub bardziej wyrazistą zmiennością sezonową średnie wartości IPW pozwalają wyodrębnić tak różne strefy klimatyczne, jak i szczególne cechy klimatu lokalnego.

7

Opóźnienie troposferyczne GNSS i jego zastosowanie do badań stanu atmosfery

Kruczyk M.

Prace Naukowe Politechniki Warszawskiej. Geodezja

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2013

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z. 54

3--150

EN

Work provides various empirical evidences on need for close cooperation of satellite geodesy and meteorology (and numerical weather prediction). Standard GNSS tropospheric delay products (IGS. EPN) show some inconsistencies, smaller after 2006 but still present (demonstrated by neat statistical analysis). Zenith Tropospheric Delay (ZTD) from GNSS solution (network or PPP) can be separated into hydrostatic part (it is a function of surface atmospheric pressure) and 'wet' part which can be transformed into IPW. Integrated Precipitable Water (or Integrated water Vapour - IWV) - column water vapour in atmosphere is highly interesting parameter of atmosphere. Amount of water vapour (here acquired by geodetic method) is crucial in thermodynamics of atmosphere (e.g. precipitation) and climate processes. Different GNSS solutions (with special case of EPN reprocessing) were verified by aerological techniques. radiosoundings and sun photometer CIMEL. It turns out that crucial problem in this comparisons is station collocation: bias and RMS depends on distance and station height. Permanent GPS station has been set up at Central Geophysical Observatory PAS (Belsk) in years 2009-2012, to carry out calibration campaign: GPS vs. sunphotometer CIMEL CF-318. IPW coming from two versions of GPS solutions (network and PPP) demonstrate deficiencies of IPW comma from sunpotometer technique. Differences were modeled by seasonal and semiannual signal, clearly CIMEL measurements are subject of systematic bias - no-linear function of atmospheric temperature. The same procedure were tried for polar stations, especially at Hornsund (Svalbard). Vertical profiles of atmospheric parameters from numerical weather prediction models can be utilized in the same way as radiosounding. Input fields (so called analysis) and first prognosis steps of model COSMO (in two versions of 14 km and 2.8 km resolution) - basic synoptic tool of Polish Institute of Meteorology and Water Management in Warsaw - were used to obtain both IPW and ZTD. Many factors were taken into account to work out optimal procedure: interpolation of data from model grid for GNSS station, corrections of height (crucial), vertical integration procedure etc. There is only slight degradation of data quality for first prognosis steps and we can get time series of IPW and ZTD with 3 h resolution Two disparate procedures for obtaining ZTD were tried: hydrostatic (only wet part from integration) and complete integration of refractivity profile in vertical direction. The second method gives in comparison with EPN combined solution quite different results for 14 ion resolution model (3 %bias), and 2.8 km resolution (0,5%bias). Use of surface meteorological data retrieved from numerical model for IPW calculation is also presented. Global model GFS (NCEP) was used only for IPW comparisons: results comparable to regional model COSMO. Topospheric delay from numerical weather model can be used in GNSS position solutions (PPP method). Horizontal coordinates estimated in PPP mode with use of COSMO model ZTD are comparable to coordinates obtained when ZTD is estimated. Vertical coordinates show greater scattering but less big outliers in case of ZTD from numerical weather model. Next topic is to analyze parameters of GNSS solutions most affecting ZTD solution: reference system shows more significance than orbits (ultra rapid or final). In the end this work demonstrates that IPW (column water) coming from satellite geodesy solutions reveals features of meteorological parameter: seasonal dependence, weather pattern changes etc. Most important application of long series od IPW of uniform quality is climatology. Work suggests how to search for climatological signal in IPW series.

8

Random Reducts : A Monte Carlo Rough Set-based Method for Feature Selection in Large Datasets

Kruczyk M., Baltzer N., Mieczkowski J., Dramiński M., Koronacki J., Komorowski J.

Fundamenta Informaticae

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2013

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Vol. 127, nr 1-4

273--288

EN

An important step prior to constructing a classifier for a very large data set is feature selection. With many problems it is possible to find a subset of attributes that have the same discriminative power as the full data set. There are many feature selection methods but in none of them are Rough Set models tied up with statistical argumentation. Moreover, known methods of feature selection usually discard shadowed features, i.e. those carrying the same or partially the same information as the selected features. In this study we present Random Reducts (RR) - a feature selection method which precedes classification per se. The method is based on the Monte Carlo Feature Selection (MCFS) layout and uses Rough Set Theory in the feature selection process. On synthetic data, we demonstrate that the method is able to select otherwise shadowed features of which the user should be made aware, and to find interactions in the data set.

9

Tropospheric delay from EPN reprocessing by WUT LAC as valuable data source - in comparison to operational EPN products and aerological data

Kruczyk M., Liwosz T.

Reports on Geodesy

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2012

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z. 1/92

109--122

EN

Standard EPN tropospheric products still show some discrepancies, prominent especially before GPS week 1400. It was one of the motives of massive reprocessing projects organised in the frame of both IGS and EPN. WUT LAC is one of Analysis Centers actively participating in EPN Reprocessing Campaign. Both operational tropospheric products and reprocessing campaign were manifold analysed. Properties of information carried in ZTD estimates were investigated both in ZTD solutions and in the form of IPW (Integrated Precipitable Water). Independent aerological data sources - radiosounding and CIMEL-318 sunphotometer were used for external verification. Authors demonstrate some results convincingly demonstrating value of reprocessed tropospheric product. Tropospheric solutions from reprocessing compared to meteorological data demonstrate better conformity. Most important application of long series ZTD’s of uniform quality is climatology. Search for climate change signal in IPW series is possible only with a reliable tropospheric solution. Reprocessing campaign results meet this requirement.

10

Activities of Józefosław Astro-Geodetic Observatory in the last five decades

Rogowski J.B., Barlik M., Litwosz T., Kruczyk M., Kujawa L., Rajner M., Olszak T., Kurka W.

Reports on Geodesy

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2010

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z. 2/89

31-52

EN

Astro-Geodetic Observatory in Józefosław, witch belongs to the Departament of Geodesy and Geodetic Astronomy of the Warsaw University of Technology, started to permanent observations in 1958. First of them was time service started in February 1958, coordinated by BIH. From 1959 astrometrial latitude measurements have been done with aim to determine the parameters of the Earth rotation. In 1991 the Observatory was joned to the International GPS Service for Geodynamics (IGS) and started to operate as a permanent one in 1993. There have been performed many observations and scientific researches, such as: GPS in the frame of IGS/IGLOS/EUREF; tidal observations; absolute gravity measurements; changes of the vertical, based on the gravimetric measurements; astrometric observations and metrology. Moreover studies on RTK and DGPS measurements using mobile phone for data transmision are performed since 1998. WUT EUREF Lokal Analysis Centre, one of the 17 Lokal Analysis Centres acting in Europe, is a very important part of the Observatory. The Centre makes continuous service of one-week and daily aolution in the farme of EPN network, processes national and international GPS campaigns (CEGRN, EXTENDED SAGET etc.), models ionosphere and troposphere parameters, compute tidal components and changes of the vertical according to astrometric and gravimetric measurenents. This paper present history and current state of the art of the Observatory's activites.

11

Tropospheric delay in GNSS and meteorological ZTD and IPW data sources

Kruczyk M.

Reports on Geodesy

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2008

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z. 2/85

125-137

12

Automatic system for GPS tropospheric delay estimation, on-line GPS processing user service and analysis of the results

Kruczyk M., Liwosz T., Rogowski J. B.

Reports on Geodesy

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2006

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z. 1/76

139-151

EN

This paper describes automatic system for GPS tropospheric delay estimation developed at the Institute of Geodesy and Geodetic Astronomy of the Warsaw University (WUT) LAC. The system is based on BPE (Bernese Processing Engine) and utilizes UltraRapid orbits and EUREF weekly coordinates. We describe processing strategies used in this application and report various experiences leading to start of NRT tropospheric service. We have made many statistical quality analysis of the resulting solutions. Accurate comparisons with ZTD combined product (EPN and IGS) and radiosounding data has been made. The poster presents also other research areas on the GPS data processing performed especially the Internet based service for an on-line GPS processing of the users data. Finally we present some other ideas of our interest how to use tropospheric delay in meteorology and climatology.

13

Geodynamic programmes conducted at Jozefoslaw Observatory

Rogowski J. B., Bogusz J., Figurski M., Kruczyk M., Kujawa L., Kurka W., Liwosz T.

Reports on Geodesy

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2005

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z. 2/73

159-170

14

Some aspects of GPS tropospheric delay behavior, usefulness and estimation

Kruczyk M., Liwosz T., Rogowski J. B.

Reports on Geodesy

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2004

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nr 2/69

235--242

EN

Our paper highlights some different areas of our research in GPS meteorology. We have made many statistical quality analysis of the many standard tropospheric solutions and ZTD combined product (EPN and IGS). This work can be useful for both combined product users and improved processing strategy guidelines. The core of our interest is tropospheric delay estimation and usage in practical activity such as permanent network and epoch campaign adjustment. We report current works leading to start of NRT tropospheric service in WUT LAC. Finally we present some interesting ideas how to use tropospheric delay in meteorology and climatology (e. g. long IPW series for different dimate conditions, IPW distribution maps, correlation of IPW series for different stations and other parameters, comparisons with radiosounding profiles, IPW derivation).

15

Research programe of the astrogeodetic observatory in Józesław

Rogowski J. B., Bogusz J., Figurski M., Kłęk M., Kruczyk M., Kujawa L., Kurka W., Liwosz T.

Reports on Geodesy

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2004

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nr 2/69

213--233

EN

Astrogedodetic Observatory Józefoslaw was joined to the IGS in 1991 and started to the permanent service in 1993. To day GPS stations JOZE and JOZE working in the frame IGS/EUREF. JOZ2 station participate in IGLOS an EUREF IP pilot projects. Results of tidal gravimetric observations; absolute gravity measurements; changes of the vertical, based on the gravimetric measurements and astrometric observations; hydrological and meteorological observations are the base for study of local deformations model. The results of practical test of RTK and DGPS measurements using mobile phone for data transmission performed since 1998 are also presented in the paper. WUT EUREF Local Analysis Centre, one of the 16 Local Analysis Centres acting in Europe, is a very important part of the Observatory. The Centre makes continuous service of one-week solution in the frame of EUREF network, processes national and international GPS campaigns, models ionosphere and troposphere parameters. The part of this Centre is automatic service for GPS data processing. The results of mentioned above work are presented in the paper.

16

GPS derived integrated precipitable water-some remarks and proposed applications

Kruczyk M., Rogowski J.

Reports on Geodesy

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2002

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z. 1/61

183-195

17

WUT LAC status report

Bogusz J., Figurski M., Kruczyk M., Kujawa L., Liwosz T., Pfeil M., Rogowski J.

Reports on Geodesy

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2001

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z. 3/58

67-72

18

On accuracy of IPWV determined from GPS networks

Kruczyk M., Rogowski J., Liwosz T.

Reports on Geodesy

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2001

|

z. 3/58

139-142

19

Analysis of integrated water vapourderived using GPS

Kruczyk M., Rogowski J., Liwosz T.

Reports on Geodesy

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2001

|

z. 2/57

161-167

EN

Various numerical experiments concerning determination of IWV over permanent GPS stations in Central Europe are reported here. We analysed changes of the formula for mean temperature from radiosounding (conducted by Polish Institute of Meteorology and Water Management). Radiosonde and numerical weather model - derived IWV were compared to postprocessed solutions for GPS stations. Different: GPS solutions (both daily and hourly, applying different orbit products), hydrostatic and dry models, real and model assimilated meteo data were compared and analysed.

20

Activities of astro-geodetic observatory in Jozefoslaw in 2000

Bogusz J., Figurski M., Kruczyk M., Kujawa L., Kurka W., Litwosz T., Pfeil M., Rogowski J.

Reports on Geodesy

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2001

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z. 2/57

153-159

EN

Astro-geodetic Observatory of the Institute of Geodesy and Geodetic Astronomy of the Warsaw University of Technology in Józefosław was incorporated in 1957. In 1991 it was joined to the International GPS Service for Geodynamics (IGS) and started to operate as a permanent one in 1993. Since then the following permanent services have been maintained: GPS observations using Trimble and Turbo Rogue receivers, tidal gravimetric observations with LaCoste&Romberg model D gravimeter and meteorological obseryations. Since 1995 WUT Local Analysis Centre, one of the 13 local Analysis Centres acting in Europe, has started the systematic day-to-day processing of the selected number of European sites in the frame of the EUREF network. It processes national and International GPS campaigns (CEGRN, EXTENDED SAGET etc.), models ionosphere and troposphere parameters, compute tidal components and changes of the vertical according to astrometric and gravimetric measurements. For last 5 years the Centre has processed and analysed many of scientific researches carried out in within the confines of the Central European Initiatiye (CEI). This paper presents state of the art of the Observatory's actiyities. It deals with the acting of it and participating of the WUT Local Analysis Centre to the international scientific projects.