Papers by Jacek Paziewski
Mining as well as natural hazards can result in land subsidence and may consequently cause disast... more Mining as well as natural hazards can result in land subsidence and may consequently cause disasters with threat to human life and damage to human property. Determination of deformation indices at area being under influence of open pit mine requires high precision geodetic surveys in order to allow for alerting the plausible hazards. In this paper there are presented the principles of the precise determination of the three dimensional displacements with the use of GPS technology elaborated at the University of Warmia and Mazury in Olsztyn. The presented technology has been in use for several years at the area of open pit mine “Adamów SA ” in Turek. The technology of field measurements together with the construction of the control network and the observational session was presented. The emphasis was put on the post-processing strategy in precise local satellite networks. Results show that it is possible to achieve 2-3 mm accuracy of 3-D coordinates of the monitored points.
Preliminary results on performance of new ultra-fast static positioning module – POZGEO-2 in area... more Preliminary results on performance of new ultra-fast static positioning module – POZGEO-2 in areas outside the ASG-EUPOS network
Acta Geodynamica et Geomaterialia, 2016
Nowadays, the high accuracy of the horizontal coordinates obtained from GNSS measurements is easi... more Nowadays, the high accuracy of the horizontal coordinates obtained from GNSS measurements is easily achievable. On the other hand, the precision of GNSS-derived heights is clearly lower. Nevertheless, state of the art measurement technique, field surveying equipment, data processing software and algorithms allow achieving millimeter-level accuracy for ellipsoidal heights. However, in order to obtain the normal heights from GNSS measurements, the application of precise quasigeoid model is necessary. Nowadays, there are several available guasiqeoid models covering the area of Poland, e.g. PL-geoid-2011; EGM2008; "leveling geoid 2001"; European Gravimetric Quasigeoid model EGG2008. In addition, a high-accuracy regional quasigeoid model for the Lower Silesia region was developed in 2015. In this paper, we investigate performance of the application of the selected quasigeoid models to satellite leveling on the basis of test precise leveling network established at the area of Lower Silesia in Poland. In this region, simultaneous precise geometric and satellite leveling measurements were carried out on over 1000 km of leveling lines and over 100 GNSS sites. The results show that the current relative accuracy of the most accurate geoid models is better than 10 mm.
GPS Solutions
We analyze the observation quality, assess the performance and identify the constraints of quadru... more We analyze the observation quality, assess the performance and identify the constraints of quadruple-constellation single-frequency ionospheric-free precise point positioning (SF-IF PPP) with low-cost receivers. It is revealed that low-cost receivers with patch antennas exhibit lower C/N0 records and a weaker elevation dependence of C/N0 than the high-grade equipment. The results demonstrate that low-cost receivers can offer code measurements with similar noise compared to high-grade receivers providing that the multipath effect is eliminated. Regarding positioning performance, it is shown how SF-IF PPP for the high-grade receiver converges approximately two times faster than for the low-cost receiver with a patch antenna. It is confirmed that an application of a survey-grade antenna instead of the patch one noticeably enhances the performance of low-cost receiver SF-IF PPP. The study also reveals that the multipath effect is a dominant factor that constrains the performance of SF-I...
Geodesy and Cartography, 2019
This review paper presents research results on geodetic positioning and applications carried out ... more This review paper presents research results on geodetic positioning and applications carried out in Poland, and related to the activities of the International Association of Geodesy (IAG) Commission 4 “Positioning and Applications” and its working groups. It also constitutes the chapter 4 of the national report of Poland for the International Union of Geodesy and Geodynamics (IUGG) covering the period of 2015-2018. The paper presents selected research, reviewed and summarized here, that were carried out at leading Polish research institutions, and is concerned with the precise multi-GNSS (Global Navigation Satellite Systems) satellite positioning and also GNSS-based ionosphere and troposphere modelling and studies. The research, primarily carried out within working groups of the IAG Commission 4, resulted in important advancements that were published in leading scientific journals. During the review period, Polish research groups carried out studies on multi-GNSS functional position...
Biuletyn Wojskowej Akademii Technicznej, 2012
determination of deformation indices, like vertical and horizontal displacements, requires high p... more determination of deformation indices, like vertical and horizontal displacements, requires high precision geodetic surveys. in the classic surveying, the precise, geometrical leveling is commonly used in order to determine vertical displacements and angle-distance measurements in control network in order to determine horizontal displacements. The paper presents the main principles and steps of precise determination of the 3-d displacements with the use of GPs technology. The technology of field measurements together with the construction of the control network and the observation processing methodology is presented. The emphasis was put on the data post-processing strategy in precise, local satellite networks. The presented achievable accuracy is confirmed after several years of the experience gained during field campaigns at the open pit mine adamów and the Main and old city of Gdańsk. The results show that it is possible to achieve 2-3 mm accuracy 3-d coordinates of the monitored ...
<p>This study assesses the quality of multi-constellation GNSS observations of selected And... more <p>This study assesses the quality of multi-constellation GNSS observations of selected Android smartphones namely Huawei P30, Huawei P20 and Huawei P Smart as well as Xiaomi Mi 8 and Xiaomi Mi 9. We investigate the properties of phase ambiguities to anticipate the feasibility of precise positioning with integer ambiguity fixing. The results reveal a significant drop of smartphone carrier-to-noise density ratio (C/N0) with respect to geodetic receivers and discernible differences among constellations and frequency bands. We show that the higher the elevation of the satellite, the larger discrepancy in C/N0 between the geodetic receivers and smartphones. We depict that an elevation dependence of the signal strength is not always the case for the smartphones. We discover that smartphone code pseudoranges are noisier by about one order of magnitude as compared to the geodetic receivers, and that the code signals on L5 and E5a outperform these on L1 and E1, respectively. It was shown that smartphone phase observations are contaminated by the effects that can destroy the integer property and time-constancy of the ambiguities. The long term drifts were detected for GPS L5, Galileo E1, E5a and BDS B1 phase observations of Huawei P30. To isolate the observational noise from low frequency effects we take advantage of time differencing using the variometric approach. These investigations highlight competitive phase noise characteristics for the Xiaomi Mi 8 when compared to the geodetic receivers. We also reveal poor phase signal quality for the Huawei P30 smartphones related to the unexpected long-term drifts of the phase signals. The observation quality assessment is supported with the evaluation of a positioning performance. We proved that it is feasible to obtain a precise solution in a smartphone to smartphone relative positioning mode with fixed ambiguities. Such results move us towards a collaborative precise positioning with smartphones.</p>
Annals of Geophysics, 2016
Total electron content (TEC) fluctuation in the ionosphere is one of the main unresolved problems... more Total electron content (TEC) fluctuation in the ionosphere is one of the main unresolved problems degrading ambiguity resolution and thus affect the reliability of satellite positioning. With regard to conditions prevailing at mid-latitudes, the impact of the upper atmospheric layers is primarily associated with the occurrence of medium-scale traveling ionospheric disturbances (MSTIDs). This study contains the combined analysis involving MSTIDs patterns observed in raw phase data and their impact on rapid static positioning. The first part is aimed at discrepancies in wavelike MSTIDs signatures detected in time series of high elevated measurements. It was demonstrated that the differences in slant ionospheric delays at medium baselines often exceed 0.5 TEC units and more importantly, the detected MSTIDs patterns were highly mutable. The next section presents the impact of MSTIDs on double differenced ionospheric delays and performance of rapid static positioning. The positioning was...
2018 Baltic Geodetic Congress (BGC Geomatics), 2018
Reliable GNSS positioning is a challenging task at the high-latitudes since these areas are a sub... more Reliable GNSS positioning is a challenging task at the high-latitudes since these areas are a subject of frequent occurrence of ionospheric disturbances. Considering the above, this study presents both methodology and performance assessment of the original algorithm aimed at the mitigation of the ionospheric delay variability in precise GNSS positioning. The algorithm is based on the rate of TEC equation and allows elimination of the temporal changes of the ionospheric delays. The experimental verification of the methodology was performed on the basis of multi-station medium-range RTK positioning using data collected in December 2017 at permanent stations located near the south geomagnetic pole. The results confirmed a drop of ambiguity resolution efficiency during space weather events for a standard geometry-based relative positioning model. On the contrary the results obtained with the application of the proposed algorithm demonstrated a clear enhancement in the ambiguity resoluti...
2017 Baltic Geodetic Congress (BGC Geomatics), 2017
The test shown in this paper is intended to check if the technology of the global navigation sate... more The test shown in this paper is intended to check if the technology of the global navigation satellite systems (GNSS) allows realtime monitoring of more stiffer civil structures with fundamental frequencies about 3–5 Hz and dynamic displacements in the order of a few millimeters. The technical feasibility is illustrated through a simple and inexpensive experiment using a standard stock steel bar to simulate vibration of a building as a vertical cantilever beam. Information on dynamic displacements were obtained both from signals recorded by GNSS receivers and accelerometers. It seems that both instruments can provide sufficiently accurate measurements of relative horizontal displacements allowing dynamic characteristics of the vibrating systems to be accurately identified.
The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) represents a complete threedim... more The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) represents a complete threedimensional data assimilation system comprised of data quality control, analysis, initialization, and forecast model components. COAMPS has been developed by the Marine Meteorology Division (MMD) of the Naval Research Laboratory (NRL). The U.S. Navy uses the system for short-term numerical weather predictions for various regions of the world. Currently COAMPS ver.3.1 is also operated and tested at the Department of Civil Engineering and Geodesy of the Military University of Technology, Warsaw, Poland (MUT). It is primarily used for military applications, but also a new module has been developed to provide tropospheric zenith total delays (ZTD) for stations of the Polish part of the European Position Determination System (EUPOS). ZTDs can be obtained in both near-real time and several hours ahead.
In precise GNSS positioning, the correlated tropospheric effects are usually reduced by double di... more In precise GNSS positioning, the correlated tropospheric effects are usually reduced by double differencing of the observations and applying mathematical atmospheric models. However, with a growing distance between the receivers, the tropospheric errors decorrelate causing large residual errors affecting positioning quality. These errors mostly concern the height component of the user position and are related to a high correlation of this component with zenith tropospheric delays (ZTD). This is why nowadays the troposphere is considered as an ultimate accuracy limiting factor in geodetic applications of GNSS. Currently, the most popular solution in the state of the art applications is to estimate ZTD together with station coordinates in the common data adjustment. This approach requires long data spans, e.g., at least 30-60 minutes. However, in fast-static positioning when short data spans (a few minutes only) are available, this method in not feasible and the troposphere is very difficult to model. Therefore, fast-static positioning requires external tropospheric information in order to improve its accuracy. This can be achieved by a network of the reference GNSS stations (GBAS), where ZTD can be obtained in the adjustment of GNSS data or directly from the ground meteorological data in near real-time (NRT) and provided as an external supporting product. The presented research are carried out in the frame of the “ASG+” project aimed at the development of NRT supporting modules for the ASG-EUPOS system. In this paper we present the analysis of the application of several ZTD modeling techniques to fast-static GNSS positioning, namely: (1) NRT ZTD estimates obtained based on GNSS data from Polish GBAS system called ASG-EUPOS and IGS/EPN and IERS products, (2) NRT ZTD determination based on meteorological data collected in real time from ASG-EUPOS, METAR and SYNOP systems. In order to assess the accuracy of these ZTD modeling techniques, test baselines of several tens of kilometers were processed in fast-static mode using in-house developed GINPOS software. A 24-h data set was divided into 288 sessions, each of 1- or 5-minute long. Each session was processed independently and the obtained coordinate residuals were analysed. Four different approaches to the troposphere modelling were applied and tested: a) using a standard mathematical atmosphere model, b) using ZTD estimates based on GNSS data, c) using NRT ZTD estimates based on GNSS data, d) using NRT ZTD estimates based on meteorological data. The results show that NRT ZTD products can improve both the accuracy and the reliability of the fast static positioning, what is of special interest to field surveyors. The most noticeable effect is observed in the station height component estimation. In some extreme cases, mismodelling of the troposphere may even disrupt ambiguity resolution and, therefore, prevents user from obtaining accurate position.
The monitoring of static and dynamic deformations of buildings and other engineering structures i... more The monitoring of static and dynamic deformations of buildings and other engineering structures is of greatinterest for many scientific and practical reasons. Such measurements provide information required for safe maintenanceof the constructions being a subject of various excitations. At present one of the most commonly used technologyfor this purpose is the high-rate GNSS positioning. The application of GNSS technology with appropriate processingmethodology may meet the specific requirements which result in extraction of information on dynamic displacementsand deformations of ground and engineering structures. The high temporal resolution and precision ofGNSS phase observations predestine this technology to be applied to the most demanding applications in terms of accuracy,availability and reliability. In this study we present preliminary results of application of precise GNSS positioningfor detection of small scale (centimeter level) dynamic displacements. In the first part of wo...
The Medium Scale Travelling Ionospheric Disturbances (MSTIDs) are the most frequent wave signatur... more The Medium Scale Travelling Ionospheric Disturbances (MSTIDs) are the most frequent wave signatures in the ionosphere, with amplitudes up to several TECUs, periods from several hundreds to one-two thousands of seconds, and propagation velocities from 50 to +300 m/s, mainly equator-eastward in winter/fall seasons, and westward in summer/spring seasons (M. Hernandez-Pajares et al., Radio Science, doi:10.1029/2011RS004951, 2012). Although their amplitude in not very important in relative terms, compared with the typical background electron content, MSTID’s undulatory nature makes them likely the main non-linear error affecting precise GNSS processing, for instance in Wide Area RTK or either RTK techniques.
Measurement Science and Technology, 2021
Jacek Paziewski1,∗, Allison Kealy, Vassilis Gikas and Jianghui Geng 1 University of Warmia and M... more Jacek Paziewski1,∗, Allison Kealy, Vassilis Gikas and Jianghui Geng 1 University of Warmia and Mazury in Olsztyn, Olsztyn, Poland 2 RMIT University, Melbourne, Australia 3 National Technical University of Athens, Athens, Greece 4 GNSS Research Center, Wuhan University, Wuhan, People’s Republic of China ∗ Author to whom any correspondence should be addressed. E-mail: [email protected]
Mining as well as natural hazards can result in land subsidence and may consequently cause disast... more Mining as well as natural hazards can result in land subsidence and may consequently cause disasters with threat to human life and damage to human property. Determination of deformation indices at area being under influence of open pit mine requires high precision geodetic surveys in order to allow for alerting the plausible hazards. In this paper there are presented the principles of the precise determination of the three dimensional displacements with the use of GPS technology elaborated at the University of Warmia and Mazury in Olsztyn. The presented technology has been in use for several years at the area of open pit mine “Adamow SA” in Turek. The technology of field measurements together with the construction of the control network and the observational session was presented. The emphasis was put on the post-processing strategy in precise local satellite networks. Results show that it is possible to achieve 2-3 mm accuracy of 3-D coordinates of the monitored points.
An instantaneous (single-epoch) long-range RTK positioning using data from multiple Global Naviga... more An instantaneous (single-epoch) long-range RTK positioning using data from multiple Global Navigation Satellite Systems (GNSS) is currently being implemented and tested in the GINPOS software, developed at the University of Warmia and Mazury in Olsztyn. The instantaneous ambiguity resolution has several advantages; it is resistant to negative effects of cycle slips, receiver loss of lock, power and communications outages and there is no need for re-initialization immediately following loss-of-lock. The use of several GNSS systems in instantaneous kinematic positioning significantly increases the distance over which carrier-phase ambiguities can be recovered to their integer values. It also improves the reliability and integrity of the ambiguity resolution. In this work, satellite data from GPS and Galileo systems were processed. Since currently there are just two Galileo In-Orbit Validation (IOV) satellites on orbit, Spirent multi-GNSS hardware simulator was used to obtain Galileo a...
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Papers by Jacek Paziewski