Achieving single meter positioning accuracy by portable mobile devices still poses a major challenge to the satellite signal receivers constructors, despite gradual constellation completing process ...and the progress achieved in last decades. Nowadays popular smartphones are multifunctional devices that serve also as a personal navigation tool in navigation and sport activities using the global navigation satellite systems (GNSS) receivers installed. It would seem that introducing newer models to the global market would cause constant progress in the accuracies obtained, however, the study results do not confirm that. This study focused on Galaxy series smartphones of Samsung, one of the leading manufacturers worldwide, to examine its technological progress. The aim was to verify the thesis using statistical models and analyses to compare succeeding generations of smartphones on six devices from the series. The authors conducted two synchronous stationary measurement campaigns of 24 and 12 hours with one-second interval in obstacle-free environment which provided 70000+ and 30000+ statistical samples of position measurements. The reference values of true smartphones coordinates were determined by means of state-of-the-art precise surveying instruments and geodetic calculations. The results indicate that two newest generations of the Galaxy series included in the research, namely S6 and S7, obtained lower accuracies than their predecessors. Against the backdrop of lack of public availability of smartphones technical parameters, the conducted research results are relevant especially to smartphones positioning service users community.
The main factors influencing the shape of the beach, shoreline and seabed include undulation, wind and coastal currents. These phenomena cause continuous and multidimensional changes in the shape of ...the seabed and the Earth’s surface, and when they occur in an area of intense human activity, they should be constantly monitored. In 2018 and 2019, several measurement campaigns took place in the littoral zone in Sopot, related to the intensive uplift of the seabed and beach caused by the tombolo phenomenon. In this research, a unique combination of bathymetric data obtained from an unmanned surface vessel, photogrammetric data obtained from unmanned aerial vehicles and ground laser scanning were used, along with geodetic data from precision measurements with receivers of global satellite navigation systems. This paper comprehensively presents photogrammetric measurements made from unmanned aerial vehicles during these campaigns. It describes in detail the problems in reconstruction within the water areas, analyses the accuracy of various photogrammetric measurement techniques, proposes a statistical method of data filtration and presents the changes that occurred within the studies area. The work ends with an interpretation of the causes of changes in the land part of the littoral zone and a summary of the obtained results.
Theoretical nominal GPS orbits are parallel and share six ascending nodes of orbital planes. However, due to the perturbations and continuous modernization of the system, this state does not occur. ...The configuration of satellite orbits is continuously monitored by the control segment and presented regularly in the form of a GPS almanac. Almanacs, however, do not contain a parameter defining the convergence of orbits. This work presents a novel method of assessment of the configuration of orbit ascending nodes compared with the nominal constellation state. The method is a tool for space segment monitoring and detection of anomalies. The source data were 7035 System Effectiveness Model almanacs published from the 847th to 2123rd GPS weeks (March 1996–September 2020). The algorithm uses the procedure of assigning satellites to orbital planes and both the robust estimation and the least-squares methods to determine the estimates of the angular separation of orbit ascending nodes. A long-term analysis of the symmetry and trend of changes in the position of the ascending nodes was conducted. The study showed the occurrence of significant anomalies. The research provides information on the trend of satellite orbit separations and deviations of orbital planes from the initial hexagonal GPS symmetry.
The article discusses an important issue in connection with the technique of mobile Global Navigation Satellite System (GNSS) measurements of railway track coordinates, which is digital filtering ...performed to precisely determine railway track axes. For this purpose, a measuring technique is proposed which bases on the use of a measuring platform with a number of appropriately distributed GNSS receivers, where two of them determine the directional base vector of the platform. The receivers used in the research had high measuring frequency in the Real Time Kinematic (RTK) operating mode and enabled correction of the obtained results in post–processing. A key problem discussed in the article is the method for assessing the quality of the measurement results obtained from GNSS receivers, and their preparation for further processing making use of geometrically constrained parameters of the base vector and specialized digital filtering, among other elements, to precisely determining the track axis. The obtained results confirm the applicability of the used method of GNSS signal processing.
The study aims to assess the applicability of the ordinary least squares method, robust estimation, and conditions-binded adjustment in processing the six synchronous coordinate pairs of global ...navigation satellite system (GNSS) receivers. The research is part of the research project InnoSatTrack, focused on the enhancement of the determination of geometrical parameters of railway tracks using GNSS, inertial, and other sensors. A fixed frame of installation of six receivers is used in the data processing. Due to the limited availability of railway routes for measurements, the stationary campaign was conducted to gather data for the adjustment procedures tests. Six GNSS receivers in the frame-restricted configuration were set up using the tachymetric method for recording 96,729 synchronous static observations. Post-processed coordinates of the receivers were adjusted according to the geometrical conditions of the survey frame. Analysis showed higher applicability of the conditions-binded method than other estimation methods by obtaining superior results in both the precision and the maintenance of the design conditions factors than in the OLS and robust estimators.
The theory of cartographic projections is a tool which can present the convex surface of the Earth on the plane. Of the many types of maps, thematic maps perform an important function due to the wide ...possibilities of adapting their content to current needs. The limitation of classic maps is their two-dimensional nature. In the era of rapidly growing methods of mass acquisition of spatial data, the use of flat images is often not enough to reveal the level of complexity of certain objects. In this case, it is necessary to use visualization in three-dimensional space. The motivation to conduct the study was the use of cartographic projections methods, spatial transformations, and the possibilities offered by thematic maps to create thematic three-dimensional map imaging (T3DMI). The authors presented a practical verification of the adopted methodology to create a T3DMI visualization of the marina of the National Sailing Centre of the Gdańsk University of Physical Education and Sport (Poland). The profiled characteristics of the object were used to emphasize the key elements of its function. The results confirmed the increase in the interpretative capabilities of the T3DMI method, relative to classic two-dimensional maps. Additionally, the study suggested future research directions of the presented solution.
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•Novel method of inclined symmetrical structures geometry assessment.•Point cloud spatial expansion method application.•Symmetry analysis case study of the Leaning Tower of Pisa.
The ...study develops the Point Cloud Spatial Expansion (PCSE) method by introducing the procedure of verticalization of point clouds. The inclined axis of a sloped symmetrical object causes distortions in the PCSE datasets, and its content is inconsistent with the actual state of the structure. By using the Errors-In-Variables estimation, the course of the inclined axis of symmetry of the object is determined. The processed data set ensures the correct results of the PCSE method. The practical verification of the algorithm was carried out on a point cloud of one of the most characteristic inclined buildings in the world – the Leaning Tower of Pisa (Italy). The study proved the validity of introducing the point cloud verticalization procedure in the PCSE, which resulted in gaining additional features of universality and efficiency of the method.
Historical parks and palace and park complexes deserve special protection for their potential and as the embodiment of national heritage. Most of them are impressive estates that bear witness to ...their times and reflect the dreams and aspirations of their owners. However, because of the entangled history of post-socialist countries including Poland much of the cultural heritage they represent has been irreversibly destroyed. The aim of the study was to assess the concept of culture-led regeneration as applied to palace and park complexes situated in rural areas at risk of marginalisation in a post-socialist country, Poland, using the case of Kujawsko-Pomorskie Voivodeship. Its findings show that culture-led regeneration is a valuable instrument for protecting historical palace and park estates, which saves the areas from further devastation and boosts local development.
•A new method of elaborating the results of geodetic measurements (Msplit♢ estimation).•Measurement of displacements by using the Msplit and Msplit♢ estimation method.•Application of Msplit and ...Msplit♢ estimation in the PCSE method.•Strengthening the Identification of Observations with Split Functional Models.•Investigation of the robustness properties of Msplit♢ estimation.
This article addresses the issue of raising the level of identification of observations with either single or more split functional models in the squared Msplit(q) estimation process. The theoretical part of the study presents the theoretical grounds for the classical method for estimating parameters in a split functional model and proposes a modification of the computational algorithm to increase the quality of the determinations obtained. Theoretical considerations were verified through numerical tests concerning, e.g. issues of geodetic surveying practice and civil engineering.
•Innovative method of determining GNSS receiver errors in dynamic measurements.•Measurements performed under dynamic conditions.•Low-cost GNSS receivers used in sports & recreation differ ...significantly from each other.•Although oldest devices are still fully functional, the newest are more accurate.•No considerable differences in GNSS receiver accuracy during the surveys carried out at different speeds.
The article attempts to assess the positioning accuracy of a series of twelve low-cost, code GNSS receivers, manufactured by a single producer (Garmin) in the years 2003–2019, dedicated to runners. The use of such devices in recreation and sports is widespread, but they differ from each other depending on Global Navigation Satellite Systems used and individual characteristics. The surveys were carried out with the use of experimental railway measurement platform, at three speeds (10, 30, 50 km/h). The position accuracy measures commonly used in geodesy and navigation were calculated, as well as Cross Track Error measure for two confidence levels of 68% and 95%. The results demonstrated improvements in accuracy, primarily because of the number of GNSS systems used; e.g. 2011 GPS-only receiver 2DRMS = 10.35 m; 2015 GPS/GLONASS 2DRMS = 8.14 m and 2019 GPS/GLONASS/Galileo 2DRMS = 4.29 m. The test speed did not have a significant effect on the accuracy of the devices.
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