An analytical approach to single-frequency precise point positioning (PPP) is discussed in this paper. The use of the GRAPHIC ionosphere-free linear combination that is based on single-frequency phase and code observations eliminates the ionosphere bias; however, the rank deficient Gauss–Markov model is obtained. On the basis of S-transformation we prove that the single-frequency PPP represents an unbiased estimator for station coordinates and troposphere parameters, while it presents a biased estimator for ambiguities and receiver-clock error parameters. We also show that any other particular solution on the basis of S-transformation is obtained only when the common least-squares estimation in single step is applied. The recursive least-squares estimation with parameter pre-elimination only determines the vector of unknowns as possible to transform through S-transformation, whereas the same does not hold for the cofactor matrix of unknowns. The method was validated on a set of permanent stations on a territory of Europe and Slovenia, where a centimetre precision for static and a decimetre precision for kinematic survey were obtained.
COBISS.SI-ID: 7055713
A completely automatic processing chain for orthorectification of optical pushbroom sensors is presented. The procedure is robust and works without manual intervention from the arrival of the raw satellite image to orthoimage generation. It is modularly divided in three main steps: automatic GCP extraction, geometric modelling and orthorectification. The GCP extraction step uses georeferenced vector road map as a reference and produces a file with a list of GCPs coordinates and their accuracy estimation. The usability of the method is presented by testing three RapidEye images of regions with different terrain configuration. Various tests to verify the efficiency of the procedure and to make it more robust were carried out. The geometric model achieved sub-pixel accuracy in the independent check points whereas the positional accuracy of the orthoimages was around one pixel. The proposed procedure is general and can be easily adapted to various sensors.
COBISS.SI-ID: 38502189
Geographical information is connected to everyday life in many ways. Web cartography has made geospatial data more available to the public. In the next few years, the average age of the population will be over 51 years, with more than 15% of the population over the age of 65 years. The fact that the senior population is increasing suggests that online mapping and map viewer design should be aware of the senior population%s visual restrictions, as well as restrictions of other potential map users, including colour-vision-impaired users. This paper describes the senior population%s visual restrictions that can be compared with colour-vision-impaired users and provides guidelines with regard to online mapping and map viewer design for this growing segment of the elderly population.
COBISS.SI-ID: 6602081
In order to ensure safe operation of tall industrial chimneys their verticality needs to be accurately monitored. Vertical plumbing, the classic geodetic procedure for detecting the inclination has certain drawbacks and can be replaced by modern technology if necessary. In this article we are going to propose a more general and rigorous procedure, which includes measurements that result in point clouds, and explain the processing of this type of data. In our case study we used two types of modern geodetic instruments: the most accurate total station (TPS) Leica TS30 and the terrestrial laser scanner (TLS) Riegl VZ- 400. Data acquired with these instruments were fit to a cylinder using the least squares adjustment and the results were compared. The article points out the differences between the used technologies as well as the differences between the results. During the study certain questions arose and we tried our best to explain and solve them. These included: the outlier detection and removal, the influence of large amounts of data on processing time and accuracy estimates, the influence of angle of incidence of laser beam on the chimney%s inclination. In the end the deviations from the best fitting model were investigated. The article represents a comprehensive review of the use of modern geodetic technology for solving important engineering monitoring tasks.
COBISS.SI-ID: 7179617
In the article, the past experiences in the field of land consolidation in Slovenia are presented, which are still reflected in the limited acceptability of this instrument among land owners. The current institutional (legal) framework is analysed in detail. The main objective of the research was to investigate the opinion of land consolidation participants about land consolidation. Based on the field survey conducted on a sample of private land owners involved in selected land consolidation projects we tried to define the advantages and disadvantages of the current practice. The main finding is that the active participation of land owners contributes to their comprehension of the aims and to their satisfaction with the results of the land consolidation. It has been shown that the active participation of land owners in the land consolidation is the basis for developing good practices; moreover, it affects the land owners’ perception of land consolidation. The transfer of knowledge and representation of good practices among actors are still needed, in particular because of bad experiences in the past (i.e. enforced and environmentally unfriendly projects) and the traditional emotional attachment to land among land owners.
COBISS.SI-ID: 6476641
The paper presents the results of the selection of input parameters and parameters of the approximated geometrical forms with the RANSAC algorithm (RANdom SAmpling and Consensus). The RANSAC enables us to search within a given group of points for subgroups of points that belong to a mathematically describable object or a part of an object. The number of iterations within a single repetition depends on the data, selection and settings of the in put parameters (percentage of inliers, probability and minimum number of points that uniquely define a geometrical shape). In our research we applied simulation modelling to analyse the influence of the selection of input parameters on the approximation of the sphere and plane models.
COBISS.SI-ID: 6613601
This paper presents a Wavelet Neural Network (WNN) employment for discrete precise ephemerides tabular data of Global Navigation Satellite System (GNSS) orbit approximation to obtain continuous orbit function. Orbit function is essential in positioning and navigation tasks, the advantage of continuity, however, is that it can also be used during GNSS signal interruptions. The essence of WNN continuous orbit construction is single function determination for the entire interval, while the interpolation methods follow several discrete function establishment. Specifically, we investigate the performance of the WNN continuous orbit approximation by comparison with well known polynomial and trigonometric interpolations. The experimental results show that our proposed method is superior to the traditional methods especially near the end of intervals, because they are not subject to large scale function oscillations as in the case of polynomials constructions. We propose a WNN construction using different mother functions of the WNN namely Mexican hat, Morlet function, Gaussian and Daubechies (D4) wavelet. Furthermore best algorithm for regression estimation is described; selection of neurons in the hidden layer of WNN is based on orthogonal least squares algorithm. The main objective of this article is to show that the presented method of orbit function construction could be used for GNSS ephemerides distribution and short-time prediction in the Assisted GNSS-networks.
COBISS.SI-ID: 6122081
Over the last decade, the demand for three-dimensional (3D) cadastre has increased significantly worldwide. The physical and legal complexities of the built and natural environment prompt new concepts and definitions of real property units in order to meet the demands of a today’s society and to balance private and public spatial interests. Complex 3D objects cannot be defined and registered as cadastral objects in the traditional 2D land cadastre and represented in a 2D cadastral map. The paper presents results of the research, how to upgrade the data models of the land cadastre and building cadastre to introduce a unique 3D real property cadastre in Slovenia. It has been proven the data available in the current cadastres can significantly contribute toward the 3D real property cadastre and 3D graphical representation of cadastral data; nevertheless, some additional data are needed. The minimum data required could be provided already through the current cadastral procedures.
COBISS.SI-ID: 7778657
This paper discusses methodological problems of accurate area determination in the cadaster. The paper contrasts the ambiguous legal definition of the parcel boundary and parcel area in relation to the theoretically well-defined geodetic parcel boundary and the geodetic parcel area on the reference ellipsoid. To align with the real world, parcel area must account for terrain elevation. Various approximate methods for area determination which can be used in the cadaster are tested. A highly accurate method for parcel area computation is proposed, based on an equal-area projection. Considering the geodetic parcel area as a reference, the achievable accuracy of different methods is evaluated. For this analysis, the coordinates of the parcel boundary points are treated as error-free. Finally, the relevance of various systematic errors is discussed in relation to the statistical uncertainty of the parcel area, which could be gained by an a real-time kinematic GNSS survey. A case study is presented for the territory of Slovenia, its georeferencing rules, land demarcation pattern, and characteristics of its topography. Based on the results of this study, some general recommendations for the parcel area determination are given.
COBISS.SI-ID: 7925345
Paper in most important publication in the field of remote sensing (IF: 5.103, 1 of 27). The paper deals with increase of resolution of surface temperature data for urban heat islands detection. We enhanced the spatial resolution of the SEVIRI LST over central Europe to 1000 m spatial resolution and temporal resolution of 15 min. For each SEVIRI pixel, a multiple regression was run on the low-resolution data. Regression equation was then used on the high-resolution data in order to estimate LST of high spatial and temporal resolutions. The obtained results make possible to analyse the diurnal cycle of UHI. The publication has been cited at least 70 times, at least 55 times in SCI papers.
COBISS.SI-ID: 33178669