The geodetic points that form the national geodetic network cover large areas, and the accuracy of their determination is a function of the distances between them. In mining areas, a local geodetic ...network superior in precision to the national geodetic network is required. However, it is necessary to include the geodetic points that form the local network in the national geodetic network. The present work represents the methodology for solving the mentioned purpose.
In order to monitor the landslide, a geodetic network was established in the area of the Urbas landslide, on the basis of which the movements of control points can be calculated. After various ...analyses, only two small areas near the Urbas landslide proved to be stable, so we established four reference points there. In this research we defined the geodetic datum of the geodetic network of the Urbas landslide. KEY WORDS geodetic network, Urbas landslide, sets of angles, adjustment of geodetic network, geodetic datum, stability of reference points (ProQuest: ... denotes formulae omitted.) 1 UVOD Preučevano območje je del Potoške planine, ki geografsko spada v Zahodne Karavanke, natančneje na pobočje Belščice, ki se razteza med Viševnikom nad Medjim dolom in Potoškim Stolom in je mejno območje med Slovenijo in Avstrijo (Peternel, 2017).
Global navigation satellite system-acoustic (GNSS-A) combined underwater positioning technique is widely applied in seafloor displacement monitoring and offshore exploration. The conventional GNSS-A ...positioning strategy is under the assumption of equal-precision sea-surface transducer's positions determined by GNSS positioning, which weakens the positioning accuracy of single seafloor transponder-equipped station. In this article, the extended joint adjustment (JA) of the measurements of the sea surface transducers to seafloor transponders and measurements of the transponder to transponder ranging is proposed. First, we refine the transducer-to-transponder timing observation equation system by acoustic ray-tracing strategy to reduce the sound-speed-related errors. Second, we establish the mathematical model for extended JA with inter-station ranging measurements for seafloor geodetic network (SGN) positioning. Finally, the efficacy of the proposed method is demonstrated both in simulations and in real measurement datasets. Experimental results show that the proposed method outperforms the traditional positioning methods, especially in the horizontal components.
Geodetic and topographic works determine the necessary information base and of major importance in the design and management of underground construction works (mining, hydrotechnics, roads, etc.). ...The efficiency and safety of these investments with special financial implications depend on their quality. In this context, the geodetic orientation of the underground topographic works was the main and permanent subject of study and analysis on which this scientific paper refers.
For more than a decade, the GNSS Service at the Geodetic Institute of Slovenia has been managing the national GNSS CORS network SIGNAL, and since 2016 also the GNSS part of the national Zero-Order ...Geodetic Network. During this period, different problems in the operation of CORS networks have been encountered, and much experience in the field of management and quality control of CORS networks has been gained. In cooperation with the Chair of Mathematical and Physical Geodesy and Navigation at the UL FGG and the Surveying and Mapping Authority of the Republic of Slovenia, a research project named The increase of reliability of public GNSS network SIGNAL and combined zero-order geodetic network was carried out in 2018 and 2019. Based on all the experience gained, a methodology for upgrading and improving the current procedures for management of both national CORS networks, with an emphasis on improving operational reliability and the quality control of both networks, was developed. In this article, the results of that project are presented.
Seafloor geodetic network construction involves the development of geodetic station shelter, network configuration design, location selection and layout, surveying strategy, observation model ...establishment and optimization, data processing strategy and so on. This paper tries to present main technological problems involved in the seafloor geodetic network construction, and seek the technically feasible solutions. Basic conceptions of developing seafloor geodetic station shelters for shallow sea and deep-sea are described respectively. The overall criteria of seafloor geodetic network construction for submarine navigation and those of network design for crustal motion monitoring are both proposed. In order to enhance application performances of the seafloor geodetic network, the seafloor network configuration should prefer a symmetrical network structure. The sea surface tracking line measurements for determining the seafloor geodetic station position should also adopt an approximately symmetrical configuration, and we recommend circle tracking line observations combined with cross-shaped line (or double cross-shape line) observations for the seafloor positioning mode. As to the offset correction between the Global Navigation Satellite System antenna phase center and the acoustic transducer, it is recommended to combine the calibration through external measurements and model parameter estimation. Besides, it is suggested to correct the sound speed error with a combination of observation value correction and parameterized model correction, and to mainly use the model correction to reduce the influence of acoustic ray error on the seafloor positioning. Following the proposed basic designs, experiments are performed in shallow sea area and deep-sea area respectively. Based on the developed seafloor geodetic shelter and sufficient verification in the shallow sea experiment, a long-term seafloor geodetic station in the deep-sea area of 3000 m depth was established for the first time, and the preliminary positioning result shows that the internal precision of this station is better than 5 cm.
This paper presents the reasons for the establishment, activities prior to and after the construction as well as the first results of coordinate time-series of points of the Slovenian combined ...geodetic network. The so-called zero-order geodetic network is of the highest quality, and since it connects the horizontal and vertical components of the coordinate system, it represents a framework for the realization of a unified national geodetic spatial system. From the establishment on, daily GNSS processing is performed for the analysis of time-series of coordinates of the network points. Currently, the time-series of coordinates confirm the satisfactory quality of equipment, observations and stabilization of stations. The repeatability of the coordinates is at a few-millimetre level for horizontal coordinates and at a five-millimetre level for the heights. However, the current time-series of coordinates allow only the first insight into the stability of the network points. For more definitive conclusions, it will take a few more years to acquire longer time-series of coordinates for identification of the disturbing effects for the particular station. The future activities are related to the inclusion of all satellite GNSS systems and the integration of combined geodetic network’s GNSS stations into the EUREF permanent station network, EPN, which will enable quality and continuous connection of the Slovenian coordinate system with all the ITRS and/or ETRS realizations.
Creating 3-dimensional (3D) models of underwater scenes has become a common approach for monitoring coral reef changes and its structural complexity. Also in underwater archeology, 3D models are ...often created using underwater optical imagery. In this paper, we focus on the aspect of detecting small changes in the coral reef using a multi-temporal photogrammetric modelling approach, which requires a high quality control network. We show that the quality of a good geodetic network limits the direct change detection, i.e., without any further registration process. As the photogrammetric accuracy is expected to exceed the geodetic network accuracy by at least one order of magnitude, we suggest to do a fine registration based on a number of signalized points. This work is part of the Moorea Island Digital Ecosystem Avatar (IDEA) project that has been initiated in 2013 by a group of international researchers (https://mooreaidea.ethz.ch/).
Today with the fast and powerful computers, large data storage systems and modern softwares, the probabilities distribution and efficiency of statistical testing algorithms can be estimated using ...computerized simulation. Here, we use Monte Carlo simulation (MCS) to investigate the power of the test and error probabilities of the Baarda’s iterative data snooping procedure as test statistic for outlier identification in the Gauss-Markov model. The MCS discards the use of the observation vector of Gauss-Markov model. In fact, to perform the analysis, the only needs are the Jacobian matrix; the uncertainty of the observations; and the magnitude intervals of the outliers. The random errors (or residuals) are generated artificially from the normal statistical distribution, while the size of outliers is randomly selected using standard uniform distribution. Results for simulated closed leveling network reveal that data snooping can locate an outlier in the order of magnitude 5σ with high success rate. The lower the magnitude of the outliers, the lower is the efficiency of data snooping in the simulated network. In general, considering the network simulated, the data snooping procedure was more efficient for α=0.01 (1%) with 82.8% success rate.
PDF
