The aim of this paper is the geodetic determination of vertical movements of the Earth's crust using the methods of geostatistics. A practical research is conducted for the territory of the Republic ...of Srpska and most of Bosnia and Herzegovina. A free kinematic levelling network is constructed based on the data of high accuracy levelling, and vertical velocities of levelling points (benchmarks) are determined by applying the least squares adjustment method. Spatial vertical velocities and their horizontal gradients are evaluated using geostatistical methods. These results are compared with the existing geodetic solutions and other geo-data, and areas with significant values of vertical movements of the Earth's crust are marked.
The paper proposed the optimization of the network construction timing of the control network according to the specific conditions of the survey route. Moreover, presented here are the adjustments ...according to the layout requirements of the control network layout process, strengthening the control of the line level base point during the construction process. Several optimization solutions are discussed for the special design of the level control before the construction of the long tunnel. It has been explained the methodology to introduce new Continuously Operating Reference Station (CORS) technology in railway survey and design with appropriately adjustment of the position requirements of the control network according to the specification. In order to carry out the special design of the levelling route with precision, it is advisable to set a certain stable reference point in the level control of the long line. The proposed methodology can effectively solve some problems existing in the current high-speed railway construction process, and make the precision measurement control network better for survey, design, construction, supervision and operation.
Fault detection and isolation (FDI) techniques, which are called standard parity space approach (SPSA) and optimal parity vector approach (OPVA), have been presented in literature extensively for ...engineering sensor systems or sensor networks. This paper demonstrates the abilities of these approaches to detect and isolate outliers in geodetic networks. The ability to detect and isolate outliers has been measured by computing the mean success rate (MSR) for some given probability of significance levels. These approaches have been applied to a levelling network and a Global Navigation Satellite System (GNSS) network. Different matrix decomposition techniques have been used as an alternative way to the Potter algorithm, which is used in SPSA and OPVA. It has been proven that the abilities of FDI techniques, i.e. the MSRs of OPVA, increase with regard to the ones of SPSA in the levelling network and the GNSS network especially if the significance level α is chosen as 0.001 by using Monte-Carlo simulation.
THE UNIFIED LEVELLING NETWORK OF SARAWAK AND ITS ADJUSTMENT Som, Z. A. M.; Yazid, A. M.; Ming, T. K. ...
International archives of the photogrammetry, remote sensing and spatial information sciences.,
09/2016, Letnik:
XLII-4/W1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The height reference network of Sarawak has seen major improvement in over the past two decades. The most significant improvement was the establishment of extended precise leveling network of which ...is now able to connect all three major datum points at Pulau Lakei, Original and Bintulu. Datum by following the major accessible routes across Sarawak. This means the leveling network in Sarawak has now been inter-connected and unified. By having such a unified network leads to the possibility of having a common single least squares adjustment been performed for the first time. The least squares adjustment of this unified levelling network was attempted in order to compute the height of all Bench Marks established in the entire levelling network. The adjustment was done by using MoreFix levelling adjustment package developed at FGHT UTM. The computational procedure adopted is linear parametric adjustment by minimum constraint. Since Sarawak has three separate datums therefore three separate adjustments were implemented by utilizing datum at Pulau Lakei, Original Miri and Bintulu Datum respectively. Results of the MoreFix unified adjustment agreed very well with adjustment repeated using Starnet. Further the results were compared with solution given by Jupem and they are in good agreement as well. The difference in height analysed were within 10mm for the case of minimum constraint at Pulau Lakei datum and with much better agreement in the case of Original Miri Datum.
The paper's objective is to examine strategy for monitoring the stability of levelling reference marks, which was proposed in 5, for robustness against gross errors. The strategy in question is based ...on the application of three robust estimators: R-estimate of vertical displacement (based on rank tests) and two robust estimates of the standard deviation. (Because of the estimates' properties the application of the method is for the moment limited to one dimension networks.) The present paper shows that robustness of the estimates does not result in robustness of the strategy itself. This stems from the origin of outliers. There are two sources of outliers when the stability of reference mark is tested: gross errors and unstable points. Each unstable point generates outliers. If there are too many outlying observations of this type then the strategy cannot be robust against any gross error. The present paper indicates that the robustness of the strategy is strongly dependent on the number of unstable points. Thus, the method cannot be generally regarded as robust against gross errors. However, it is advisable to know when the strategy can withstand a single gross error (or multiple gross errors) and to understand how gross errors may influence the estimation results. The theoretical properties of the estimates and of the strategy are illustrated with two numerical examples.
According to the decision of IAG Reference Frame Sub-commission for Europe (EUREF) the EVRF2007 solution as the vertical reference has to be deployed in EU countries.The new height system LAS-2000,5 ...had been enacted as the European Vertical Reference System's EVRF2007 realization in Latvia and the new geoid model LV'14 had been introduced by Latvian authority Latvian Geospatial Information Agency. However, the appreciation of the quality of quasi-geoid model LV'14 is rather contradictious among the users in Latvia. The independent estimate and comparison of the two Latvian geoid models developed till now has been performed by the Institute of Geodesy and Geoinformatics. Previous geoid model LV98 which was developed for Baltic-1977 height system almost 20 years ago is outdated now. Preparatory actions described in order to fulfil the task of comparison the geoids in two different height systems. The equations and transformation parameters are presented in this article for the normal height conversion from Baltic-1977 height system to the Latvian realization named LAS-2000,5. The comparison is performed of both Latvian quasigeoid models - the new one LV'14 and previous LV98. The quality of both models estimated by controlling the geoid heights at the properly densified GNSS/levelling network sites. The distribution of discrepancies in comparison with normal distribution N(x,µ,s) is depicted in corresponding figures. For LV'14 quasi-geoid model the standard deviation of discrepancies is 3.2 cm, 75% of discrepancies x ≤ 3.2 cm. For LV98 quasigeoid model the standard deviation of discrepancies is 4.7 cm, 80% of discrepancies x ≤ 6 cm. Without doubt, the newly developed LV'14 quasi-geoid model is of higher quality.
A height system reconstruction includes renovation of benchmark fields and geometric levelling networks. It is periodical process that has purpose to ensure reliable, quality and accurate height ...system for different users. The height system reconstruction in the Republic of Croatia is based on II NVT levelling lines (second levelling of high accuracy). Specific Croatian territorial shape and geopolitical relationships must be considered for new levelling polygons. Since the height system reconstruction in Croatia is imminent, the purpose of this article is to investigate a priori influences of levelling lines in the neighbouring countries on the quality of nodal benchmark accuracy in the new projected Croatian fundamental levelling network.
Relational Database of Three Precise Levelling Campaigns in Poland Kowalczyk, Kamil (Department of Surveying, University of Warmia and Mazury, Olsztyn); Bednarczyk, Michał (Department of Surveying, University of Warmia and Mazury, Olsztyn)
Technical sciences,
11/2009, Letnik:
12
Journal Article
Recenzirano
Four precise levelling campaigns were carried out in Poland: in 1926-1937, 1953-1955, 1974-1982, 1997-2003. The levelling data from these campaigns is stored in printed catalogues, text files and ...spreadsheets. A comprehensive analysis of this data requires its compilation in a standardized form (a database). First attempts at the standardization of precise levelling data format date back to 2002 at the University of Warmia and Mazury in Olsztyn ( _yszkowicz et al. 2002). The authors of this paper, in turn, have collected the complete data from the last three precise levelling campaigns in Poland, which gives an opportunity to standardize the levelling database structure. The subject of the paper is to provide a theoretical background and to offer a relational database of the precise levelling network in Poland, with the data from each campaign. The paper describes the data, database schemas and examples of retrieving information with SQL queries.
W Polsce przeprowadzono cztery kampanie niwelacji precyzyjnej: 1926-1937, 1953-1955, 1974-1982, 1997-2003. Materiał niwelacyjny z tych prac jest przechowywany w katalogach papierowych, plikach tekstowych oraz arkuszach kalkulacyjnych. W celu przeprowadzania szerszych analiz tych wyników należy zebrać cały materiał w jednolitej formie (bazie danych). Pierwsze próby ujednolicenia formy przechowywania danych z niwelacji precyzyjnej podjęto na Uniwersytecie Warmińsko-Mazurskim w 2002 roku ( _yszkowicz i inni 2002). Obecnie nadarzyła się okazja ujednolicenia struktury bazy danych niwelacyjnych dzięki zgromadzeniu przez autorów kompletnego materiału z trzech ostatnich kampanii niwelacji precyzyjnej w Polsce. Przedmiotem niniejszego opracowania było przygotowanie teoretyczne i praktyczne relacyjnej bazy danych sieci niwelacji precyzyjnej obszaru Polski z kolejnych kampanii. Praca zawiera opis danych z poszczególnych kampanii niwelacji precyzyjnej oraz schematy budowy tej bazy, a także przykłady uzyskiwania różnych informacji za pośrednictwem zapytań SQL.
The paper presents geodetic application of R-estimation. Proposed method concerns estimation of differences between parameters of two functional models. Such estimation seems very useful in many ...geodetic problems, e.g., when observations are disturbed with gross errors or when differences mentioned are displacements of geodetic network points. The paper presents general solutions of R-estimation but it focuses special attention on its geodetic applications. In particular, it concerns levelling networks. The estimation method proposed here can be applied, for example, to monitoring of reference mark stability. The paper presents particular solution of such problem, based on R-estimation principle. Theoretical derivations and analysis are illustrated with some numerical examples.
Praca przedstawia geodezyjne zastosowania R-estymacji. Proponowana metoda dotyczy estymacji różnic między parametrami dwóch modeli funkcjonalnych. Taka estymacja wydaje się bardzo użyteczna w rozwiązaniu wielu problemów geodezyjnych, np. kiedy obserwacje są zaburzone błędami grubymi lub kiedy wspomniane różnice są przemieszczeniami punktów osnowy geodezyjnej. Praca przedstawia ogóle rozwiązania R-estymacji, ale szczególną uwagę zwrócono na jej geodezyjne zastosowanie, przede wszystkim dotyczące sieci niwelacyjnych. Przedstawiony sposób estymacji może być na przykład stosowany do kontroli stabilności punktów nawiązania. Praca przedstawia sposób takiej kontroli oparty na ogólnych zasadach R-estymacji. Przedstawione wyprowadzenia i teoretyczne rozważania zilustrowano kilkoma przykładami numerycznymi.
V prispevku je predstavljen predlog za novo oštevilčevanje nivelmanskih poligonov in reperjev. Obravnavana je tudi analiza natančnosti izmerjenih višinskih razlik, opravljena na podlagi odstopanj ...obojestransko merjenih višinskih razlik in odstopanj pri zapiranju nivelmanskih zank. Na podlagi izravnave nivelmanske mreže in nivelmanskih poligonov je analizirana tudi natančnost na podlagi popravkov merjenih višinskih razlik in izvedena ocena natančnosti določitve nadmorske višine reperjev ; This paper presents a proposal for a new numbering of levelling polygons and benchmarks. Furthermore, an accuracy analysis is done with regard to: measured height differences, residuals calculated from differences of the forward and backward runs, residuals from loop closures, and results from network adjustments.
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