133 research outputs found
Važnost uvođenja vremenskih geoinformacija u pomorsku navigaciju
U ovom radu prikazuju se važnost i mogućnosti uvođenja vremena kao četvrte dimenzije u geoinformacije pomorske navigacije. Rad se temelji na radu Koncept pomorske četverodimenzionalne navigacije nagrađenog Rektorovom nagradom Sveučilišta u Zagrebu u svibnju 2006
Analysis of the advantage of using the SiRFStarIII architecture for navigational purposes in urban areas
Proteklih nekoliko godina tržište navigacijskih uređaja doživjelo je svoj najveći procvat - svakodnevna prisutnost navigacijskih uređaja nikad nije bila veća. Međutim, zbog sve većeg stupnja korištenja navigacijskih uređaja u urbanim sredinama, kao i građevinske ofenzive na iste, javlja se standardni problem GPS sustava - slabi signal koji vodi do manje točnosti i dugo vrijeme prvog fiksiranja rješenja pozicije (engl. Time To First Fix, TTFF). Radi poboljšanja situacije tvrtka SiRF Technology Holdings, Inc1 je proizvela novi čipset SiRFStarIII koji se odlikuje većom osjetljivošću, kratkim TTFF-om i predstavlja najnovije dostignuće u satelitskoj navigaciji. U
radu se analizira prednost korištenja SiRFStarIII čipseta u urbanim sredinama kroz nekoliko praktičnih testova na području Grada Zagreba.In the last few years the market of navigational devices experienced it’s biggest boom – their everyday
presense was never bigger. Meanwhile, because of a higher degree of use of navigational devices in urban ares as the engineering offensive on them some standard GPS problems are present – weak signal from satellites which leads to smaller accuracy and long Time To First Fix (TTFF). For a better situation, the company SiRF Technology Holdings, Inc. made a new chipset SiRFStarIII which accent is on higher sensitivity, short TTFF and represents the newest achievement in satellite navigation. This paper shows the analysis of the advantage of using the chipset SiRFStarIII in urban areas through few practical tests on the area of The City of Zagreb, Croati
Satellite radar observation feasibility for large infrastructure public works
A very large infrastructural work is being undertaken in Delft. A tunnel is going to be constructed to
replace the current rail viaduct. As in any large infrastructural work, the monitoring of the land deformations
during the period of the tunnel’s construction is highly essential. In this project, one study
was performed to analyse the feasibility of PSInSAR as an independent technique for monitoring of land
subsidence.
The driving mechanisms for deformation were studied to find out the relations among them. Soil geophysics,
hydrology, infrastructures and thermal expansion were studied in relation with deformation. Besides
these, the traditional deformation monitoring methods were also studied, since they are the competitors
of this technique. LiDAR, photogrammetry, tachymetry, levelling and GPS were considered in this study for
the comparison with radar. The major attention has been given in this study to assessment of the geolocalisation
quality of PSInSAR observations.
We have found that the accuracy and point density of PSInSAR is sufficient for deformation monitoring.
While its repeat interval might not be able to detect quick failure mechanisms, other techniques have proven
to be excellent complements for this deficiency. Radar measurements are also good for validation in
other fields, showing that they correlate well with thermal expansion and soil mechanics theory. Further
work should be directed to improving geolocalisation and deformation models
Crowdsourcing geospatial data for Earth and human observations: a review
The transformation from authoritative to user-generated data landscapes has garnered considerable attention, notably with the proliferation of crowdsourced geospatial data. Facilitated by advancements in digital technology and high-speed communication, this paradigm shift has democratized data collection, obliterating traditional barriers between data producers and users. While previous literature has compartmentalized this subject into distinct platforms and application domains, this review offers a holistic examination of crowdsourced geospatial data. Employing a narrative review approach due to the interdisciplinary nature of the topic, we investigate both human and Earth observations through crowdsourced initiatives. This review categorizes the diverse applications of these data and rigorously examines specific platforms and paradigms pertinent to data collection. Furthermore, it addresses salient challenges, encompassing data quality, inherent biases, and ethical dimensions. We contend that this thorough analysis will serve as an invaluable scholarly resource, encapsulating the current state-of-the-art in crowdsourced geospatial data, and offering strategic directions for future interdisciplinary research and applications across various sectors
- …