Pawel Wielgosz - Academia.edu (original) (raw)

Papers by Pawel Wielgosz

Sensors

In 2019, the University of Warmia and Mazury in Olsztyn, in cooperation with Astri Polska, starte... more In 2019, the University of Warmia and Mazury in Olsztyn, in cooperation with Astri Polska, started a European Space Agency (ESA) project. The purpose of the project is the development and implementation of a field calibration procedure for a multi-frequency and multi-system global navigation satellite system (GNSS). The methodology and algorithms proposed in the project are inspired by the “Hannover” concept of absolute field receiver antenna calibration; however, some innovations are introduced. In our approach, the antenna rotation point is close to the nominal mean phase center (MPC) of the antenna, although it does not coincide with it. Additionally, a National Marine Electronics Association local time zone (NMEA ZDA) message is used to synchronize the robot with the GNSS time. We also propose some modifications in robot arm movement scenarios. Our first test results demonstrate consistent performance for the calibration strategy and calibration procedure. For the global positio...

Proccedings of 10th International Conference "Environmental Engineering", 2017

GNSS is an important source of meteorological data. GNSS measurements can provide tropospheric Ze... more GNSS is an important source of meteorological data. GNSS measurements can provide tropospheric Zenith Wet Delays (ZWD) over wide area covered with permanent stations. In addition, when using surface synoptical data, GNSS can provide Integrated Water Vapor (IWV) which is very valuable information utilized in weather forecasts and severe weather monitoring. Hence, there is a need to test and validate various algorithms and software used for ZWD estimation. In this research, the accuracy of the ZWD estimates was tested using two different software packages: Bernese GNSS Software v.5.2 and G-Nut/Tefnut. In addition, their computational load was evaluated. The GNSS data were obtained from POTS permanent station, which is located in Potsdam, Germany. To validate the estimation results, the derived ZWD was transformed into the IWV, and afterwards compared to the reference IWV measured by the collocated Microwave Radiometer. In addition, the ZWD estimates were also compared to the EUREF fin...

In this report, a preliminary demonstration of the accuracy analysis of several methods of estima... more In this report, a preliminary demonstration of the accuracy analysis of several methods of estimating the ionospheric corrections, based on reference GPS permanently tracking network, is presented. The ionospheric reference “truth ” was selected as the double difference (DD) ionospheric correction, estimated from the dual frequency carrier phase data after fixing the DD ambiguities. The five ionospheric models that were tested are: 1. International GPS Service (IGS) global ionospheric map (GIM). IGS GIM is a combination of several different ionosphere models provided by IGS analysis centers (Schaer, 1999). 2. Absolute, smoothed pseudorange-based method – denoted as P4. For details, see Wielgosz et al. (2003) 3. Absolute carrier phase-based model, decomposed from double differenced ionospheric delays, denoted as MPGPS™. For details, see Kashani et al. (2004) 4. Absolute model based solely upon undifferenced dual frequency ambiguous carrier phase data – NGSa (Smith, 2004) 5. Carrier p...

Abstract. GPS technique has opened broad possibilities to study the TEC distribution on a regular... more Abstract. GPS technique has opened broad possibilities to study the TEC distribution on a regular basis. In this pa-per, the latitudinal dependence of TEC over Europe for ge-ographic latitudes ranging from 40 ◦ N to 75 ◦ N is presented. We discuss the day-to-day variations of the latitudinal TEC profiles for a period of 1999 to 2001 for both quiet and dis-turbed magnetic conditions. More than 4300 TEC profiles were created from the TEC maps with a one-hour interval. GPS data from 65 European permanent stations were used to produce the TEC maps. The comparison of GPS-derived TEC profiles with the IRI model is also discussed. Key words. Ionosphere (mid-latitude ionosphere; iono-spheric disturbances) 1

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...

The EGU General Assembly, 2017

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.

on precise GNSS processing M. Hernandez-Pajares(1), P. Wielgosz(2), J. Paziewski(2), A. Krypiak-G... more on precise GNSS processing M. Hernandez-Pajares(1), P. Wielgosz(2), J. Paziewski(2), A. Krypiak-Gregorczyk(2), K. Stepniak(2), J. Bosy(3), J. Kaplon(3), T. Hadas(3), R. Orus-Perez(4), E. MonteMoreno (1), H. Yang (1), A. Garcia-Rigo (1), and G. Olivares-Pulido (1) (1) UPC, Barcelona, Spain (manuel@ma4.upc.edu)(2) UWM, Olsztyn, Poland (p.a.wielgosz@gmail.com) (3) WUELS, Wroclaw, Poland (jaroslaw.bosy@igig.up.wroc.pl), (4) ESA-ESTEC, Noordwijk, The Netherlands (raul.orus.perez@esa.int)

Reports on geodesy, 2011

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.

Measurement, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Sensors, 2020

Precise real-time kinematic (RTK) Global Navigation Satellite System (GNSS) positioning requires ... more Precise real-time kinematic (RTK) Global Navigation Satellite System (GNSS) positioning requires fixing integer ambiguities after a short initialization time. Originally, it was assumed that it was only possible at a relatively short distance from a reference station (<10 km), because otherwise the atmospheric effects prevent effective ambiguity fixing. Nowadays, through the use of VRS, MAC, or FKP corrections, the distances to the closest reference station have been increased to around 35 km. However, the baselines resolved in real time are not as far as in the case of static positioning. Further extension of the baseline requires the use of an ionosphere-weighted model with ionospheric delay corrections available in real time. This solution is now possible thanks to the Radio Technical Commission for Maritime (RTCM) stream of SSR corrections from, for example, Centre National d’Études Spatiales (CNES), the first analysis center to provide it in the context of the International ...

Atmospheric Measurement Techniques, 2018

Though Global Navigation Satellite System (GNSS) data processing has been significantly improved ... more Though Global Navigation Satellite System (GNSS) data processing has been significantly improved over the years, it is still commonly observed that zenith tropospheric delay (ZTD) estimates contain many outliers which are detrimental to meteorological and climatological applications. In this paper, we show that ZTD outliers in double-difference processing are mostly caused by sub-daily data gaps at reference stations, which cause disconnections of clusters of stations from the reference network and common mode biases due to the strong correlation between stations in short baselines. They can reach a few centimetres in ZTD and usually coincide with a jump in formal errors. The magnitude and sign of these biases are impossible to predict because they depend on different errors in the observations and on the geometry of the baselines. We elaborate and test a new baseline strategy which solves this problem and significantly reduces the number of outliers compared to the standard strategy commonly used for positioning (e.g. determination of national reference frame) in which the pre-defined network is composed of a skeleton of reference stations to which secondary stations are connected in a star-like structure. The new strategy is also shown to perform better than the widely used strategy maximizing the number of observations available in many GNSS programs. The reason is that observations are maximized before processing, whereas the final number of used observations can be dramatically lower because of data rejection (screening) during the processing. The study relies on the analysis of 1 year of GPS (Global Positioning System) data from a regional network of 136 GNSS stations processed using Bernese GNSS Software v.5.2. A post-processing screening procedure is also proposed to detect and remove a few out-liers which may still remain due to short data gaps. It is based on a combination of range checks and outlier checks of ZTD and formal errors. The accuracy of the final screened GPS ZTD estimates is assessed by comparison to ERA-Interim reanalysis.

Journal of Geophysical Research: Solid Earth, 2017

High precision Global Navigation Satellite Systems (GNSS) positioning and time transfer require c... more High precision Global Navigation Satellite Systems (GNSS) positioning and time transfer require correcting signal delays, in particular higher-order ionospheric (I2+) terms. We present a consolidated model to correct second-and third-order terms, geometric bending and differential STEC bending effects in GNSS data. The model has been implemented in an online service correcting observations from submitted RINEX files for I2+ effects. We performed GNSS data processing with and without including I2+ corrections, in order to investigate the impact of I2+ corrections on GNSS products. We selected three time periods representing different ionospheric conditions. We used GPS and GLONASS observations from a global network and two regional networks in Poland and Brazil. We estimated satellite orbits, satellite clock corrections, Earth rotation parameters, troposphere delays, horizontal gradients, and receiver positions using global GNSS solution, Real-Time Kinematic (RTK), and Precise Point Positioning (PPP) techniques. The satellite-related products captured most of the impact of I2+ corrections, with the magnitude up to 2 cm for clock corrections, 1 cm for the along-and cross-track orbit components, and below 5 mm for the radial component. The impact of I2+ on troposphere products turned out to be insignificant in general. I2+ corrections had limited influence on the performance of ambiguity resolution and the reliability of RTK positioning. Finally, we found that I2+ corrections caused a systematic shift in the coordinate domain that was time-and region-dependent and reached up to À11 mm for the north component of the Brazilian stations during the most active ionospheric conditions.

Remote Sensing, 2017

The ionosphere is still considered one of the most significant error sources in precise Global Na... more The ionosphere is still considered one of the most significant error sources in precise Global Navigation Satellite Systems (GNSS) positioning. On the other hand, new satellite signals and data processing methods allow for a continuous increase in the accuracy of the available ionosphere models derived from GNSS observables. Therefore, many research groups around the world are conducting research on the development of precise ionosphere products. This is also reflected in the establishment of several ionosphere-related working groups by the International Association of Geodesy. Whilst a number of available global ionosphere maps exist today, dense regional GNSS networks often offer the possibility of higher accuracy regional solutions. In this contribution, we propose an approach for regional ionosphere modelling based on un-differenced multi-GNSS carrier phase data for total electron content (TEC) estimation, and thin plate splines for TEC interpolation. In addition, we propose a methodology for ionospheric products self-consistency analysis based on calibrated slant TEC. The results of the presented approach are compared to well-established global ionosphere maps during varied ionospheric conditions. The initial results show that the accuracy of our regional ionospheric vertical TEC maps is well below 1 TEC unit, and that it is at least a factor of 2 better than the global products.

This paper presents an algorithm for GNSS carrier phase positioning based on some properties of A... more This paper presents an algorithm for GNSS carrier phase positioning based on some properties of Ambiguity Function Method. There is no stage of ambiguity search/resolution in the presented approach, since there is no ambiguity parameter in the proposed adjustment model. The integer nature of the ambiguities is ensured in the results through the least squares adjustment with condition equations in the functional model. Therefore the proposed method is robust to cycle slip effect. Also, an appropriate function for the condition equations is presented and tested here. The new approach requires subsequent processing of the linear combinations of GNSS signals in the cascade adjustment. The presented numerical tests were performed using in-house developed GINPOS software and GPS data sample collected by Polish GNSS network -ASG-EUPOS.

The paper presents the results of the first GPS measurement campaign, conducted in December 2006,... more The paper presents the results of the first GPS measurement campaign, conducted in December 2006, on a network of fundamental altitude points, situated in the Main and Old City of Gdañsk.