Robusna prilagodba vertikalnih pomaka na osnovi podata GNSS mreže

Long operation periods of GNSS stations give a possibility to use the data in analyzing vertical crustal movements with the accuracy better than ± 0.5 mm/y. During the analysis, the reliability must be considered. This involves the choice of the vertical crustal movements network adjustment method. In most cases, the vertical crustal movements network models are designed as absolute and related to the ellipsoid, where the movement is calculated on the basis of estimated station coordinates. The other option is choosing differential relative models, where GNSS vector coordinates are used. In this case, GNSS stations are connected and vertical movements between them are calculated. In the next stage, the network of vertical crustal movements is adjusted and the accuracy is assessed. The aim of this article is to calculate and adjust the unadjusted trend based on GNSS time series in an area located in Central Europe. The article presents the robust adjustment method with a weighting scheme. The obtained results show that the accuracy of vertical crustal movements model of 0.5 mm/y can be obtained from the GNSS observations processing. Also the benefits coming from the application of robust adjustment method are emphasized.Na osnovi dugogodišnjeg niza podataka GNSS postaja omogućena je analiza vertikalnog gibanja kore s točnošću većom od –0,5 mm/god. Tijekom same analize potrebno je razmatrati pouzdanost, a što uključuje odabir metode DETINIRANJA MREŽE vertikalnih pomaka kore. U većini slučajeva te metode su dizajnirane apsolutne te povezane s elipsoidom, gdje se pomak računa za postaje procijenjenih koordinata. Druga mogućnost je odabir diferencijalnih relativnih modela, gdje se koriste GNSS vektorske koordinate. U tom slučaju, su postaje međusobno GNSS mreže povezane te se računa vertikalni pomaci između njih. U idućem koraku se vrijednosti pomaka kore podešavaju te se procjenjuje pouzdanost. Cilj ovog rada je izračuna i prilagodba vrijednosti vertikalnih pomaka kore na osnovi vremenskih nizova zapisa GNSS mreže postaja na području središnje Europe. Članak prikazuje robusnu metodu prilagođavanja s težinskom shemom. Dobiveni rezultati pokazuju da je na osnovi korištenih podataka GNSS mreže moguće postići pouzdanost od 0.5 mm / god. Također, naglašena je prednost primjene navedene metode

Terrestrial Laser Scanner as a Tool for Assessment of Saturation and Moisture Movement in Building Materials

Non Destructive Testing (NDT) is a key element of modern civil engineering. It is especially important in civil and structural engineering helping both in quality control of produced elements and technical assessments of existing structures. Existing NDT methods are being continuously improved and new methods are developed or adopted from different engineering fields. Terrestrial Laser Scanner (TLS) method which is commonly used for geodetic applications has a great potential to be successfully harnessed in civil and structural engineering. TLS can be used for remote sensing of saturation of building materials. A research programme was prepared in order to prove this concept. Specimens representing most popular European building materials were scanned using TLS. Tested specimens were in different saturation states including capillary rising saturation. The saturation assessment was based on differences of values of intensity. The concept proved to be feasible and technically realistic

Out-Of-Plane Displacements Determination Based on the Analysis of Point Clouds from TLS Using the M-Split Estimation

Building structures are exposed to the impact of various forces and natural phenomena. Earthquakes, heavy rains, displacements of land surrounding the building can have a significant and negative impact on the elements of buildings or entire construction objects. Terrestrial laser scanning technology can be successfully used to obtain data on changes in the structure of an object. This papier discusses the use of TLS as a measurement method for obtaining information on displacements and deformations that have occurred after heavy downpour. As a result of the rapid rain, the ground displacement occurred, which in effect led to damage to the retaining wall. The terrestrial laser scanning was used to measure the area covered by the displacements and the M-split method to model the obtained data

A Review of Tree Species Classification Based on Airborne LiDAR Data and Applied Classifiers

Remote sensing techniques, developed over the past four decades, have enabled large-scale forest inventory. Light Detection and Ranging (LiDAR), as an active remote sensing technology, allows for the acquisition of three-dimensional point clouds of scanned areas, as well as a range of features allowing for increased performance of object extraction and classification approaches. As many publications have shown, multiple LiDAR-derived metrics, with the assistance of classification algorithms, contribute to the high accuracy of tree species discrimination based on data obtained by laser scanning. The aim of this article is to review studies in the species classification literature which used data collected by Airborne Laser Scanning. We analyzed these studies to figure out the most efficient group of LiDAR-derived features in species discrimination. We also identified the most powerful classification algorithm, which maximizes the advantages of the derived metrics to increase species discrimination performance. We conclude that features extracted from full-waveform data lead to the highest overall accuracy. Radiometric features with height information are also promising, generating high species classification accuracies. Using random forest and support vector machine as classifiers gave the best species discrimination results in the reviewed publications

Robust network adjustment of vertical movements with GNSS data

Long operation periods of GNSS stations give a possibility to use the data in analyzing vertical crustal movements with the accuracy better than ± 0.5 mm/y. During the analysis, the reliability must be considered. This involves the choice of the vertical crustal movements network adjustment method. In most cases, the vertical crustal movements network models are designed as absolute and related to the ellipsoid, where the movement is calculated on the basis of estimated station coordinates. The other option is choosing differential relative models, where GNSS vector coordinates are used. In this case, GNSS stations are connected and vertical movements between them are calculated. In the next stage, the network of vertical crustal movements is adjusted and the accuracy is assessed. The aim of this article is to calculate and adjust the unadjusted trend based on GNSS time series in an area located in Central Europe. The article presents the robust adjustment method with a weighting scheme. The obtained results show that the accuracy of vertical crustal movements model of 0.5 mm/y can be obtained from the GNSS observations processing. Also the benefits coming from the application of robust adjustment method are emphasized.Na osnovi dugogodišnjeg niza podataka GNSS postaja omogućena je analiza vertikalnog gibanja kore s točnošću većom od –0,5 mm/god. Tijekom same analize potrebno je razmatrati pouzdanost, a što uključuje odabir metode DETINIRANJA MREŽE vertikalnih pomaka kore. U većini slučajeva te metode su dizajnirane apsolutne te povezane s elipsoidom, gdje se pomak računa za postaje procijenjenih koordinata. Druga mogućnost je odabir diferencijalnih relativnih modela, gdje se koriste GNSS vektorske koordinate. U tom slučaju, su postaje međusobno GNSS mreže povezane te se računa vertikalni pomaci između njih. U idućem koraku se vrijednosti pomaka kore podešavaju te se procjenjuje pouzdanost. Cilj ovog rada je izračuna i prilagodba vrijednosti vertikalnih pomaka kore na osnovi vremenskih nizova zapisa GNSS mreže postaja na području središnje Europe. Članak prikazuje robusnu metodu prilagođavanja s težinskom shemom. Dobiveni rezultati pokazuju da je na osnovi korištenih podataka GNSS mreže moguće postići pouzdanost od 0.5 mm / god. Također, naglašena je prednost primjene navedene metode

A Review of Tree Species Classification Based on Airborne LiDAR Data and Applied Classifiers

Remote sensing techniques, developed over the past four decades, have enabled large-scale forest inventory. Light Detection and Ranging (LiDAR), as an active remote sensing technology, allows for the acquisition of three-dimensional point clouds of scanned areas, as well as a range of features allowing for increased performance of object extraction and classification approaches. As many publications have shown, multiple LiDAR-derived metrics, with the assistance of classification algorithms, contribute to the high accuracy of tree species discrimination based on data obtained by laser scanning. The aim of this article is to review studies in the species classification literature which used data collected by Airborne Laser Scanning. We analyzed these studies to figure out the most efficient group of LiDAR-derived features in species discrimination. We also identified the most powerful classification algorithm, which maximizes the advantages of the derived metrics to increase species discrimination performance. We conclude that features extracted from full-waveform data lead to the highest overall accuracy. Radiometric features with height information are also promising, generating high species classification accuracies. Using random forest and support vector machine as classifiers gave the best species discrimination results in the reviewed publications

On the numerical minimisation of the objective function applied to spherical harmonics fitting

The paper presents some considerations on the performance of various objective function minimization methods in the process of GNSS antenna PCV determination. It is particulary important in the case of structural health monitoring and diagnostics. PCV are used as an additional feature to improve the GNSS positioning accuracy. The process of PCV derivation is complex and involves fitting spherical harmonics into a set of observables. The paper compares computing performance and accuracy of few methods used in the fitting process

Wpływ dołączenia obserwacji od pseudosatelity na wyrównanie sieci GPS

Tyt. z nagłówka.Bibliografia s. 109.Dostępny również w formie drukowanej.STRESZCZENIE: W artykule zaprezentowano wyniki wyrównania sieci GPS w trudnych warunkach pomiarowych. Sieć została wyrównana dwukrotnie - z oraz bez dołączonego pseudosatelity. Obliczenia zostały wykonane przy wykorzystaniu autorskiego oprogramowania umożliwiającego obliczenie wektora na podstawie obserwacji GPS i obserwacji od pseudosatelity. Wpływ dołączenia pseudosatelity na wyrównanie sieci określony został na podstawie porównania wyników wyrównania sieci GPS bez utrudnień, GPS z utrudnieniami oraz GPS+PL z utrudnieniami. SŁOWA KLUCZOWE: GPS, pseudosatelita, sieć. ABSTRACT: This paper presents results of GPS network adjustment in difficult survey environment. Network was adjusted twice - with and without pseudolite observation. Calculations were made with authors own software for GPS and pseudolite data processing. The influence of pseudolite observation on GPS network adjustment was evaluated from differences between GPS only survey with no obstructions and survey with obstructions with and without pseudolite. KEYWORDS: GPS, pseudosatelite, networks

JupyTEP IDE as an Online Tool for Earth Observation Data Processing

The paper describes a new tool called JupyTEP integrated development environment (IDE), which is an online integrated development environment for earth observation data processing available in the cloud. This work is a result of the project entitled “JupyTEP IDE—Jupyter-based IDE as an interactive and collaborative environment for the development of notebook style EO algorithms on network of exploitation platforms infrastructure” carried out in cooperation with European Space Agency. The main goal of this project was to provide a universal earth observation data processing tool to the community. JupyTEP IDE is an extension of Jupyter software ecosystem with customization of existing components for the needs of earth observation scientists and other professional and non-professional users. The approach is based on configuration, customization, adaptation, and extension of Jupyter, Jupyter Hub, and Docker components on earth observation data cloud infrastructure in the most flexible way; integration with accessible libraries and earth observation data tools (sentinel application platform (SNAP), geospatial data abstraction library (GDAL), etc.); adaptation of existing web processing service (WPS)-oriented earth observation services. The user-oriented product is based on a web-related user interface in the form of extended and modified Jupyter user interface (frontend) with customized layout, earth observation data processing extension, and a set of predefined notebooks, widgets, and tools. The final IDE is addressed to the remote sensing experts and other users who intend to develop Jupyter notebooks with the reuse of embedded tools, common WPS interfaces, and existing notebooks. The paper describes the background of the system, its architecture, and possible use cases