Design Of Geodetic Networks Research Articles

Multi-Criteria Optimization of Special-Purpose Geodetic Network Using the Vikor Method

This paper discusses and applies an approach for the design of a geodetic network intended to serve as an adequate basis for analyzing the verticality of buildings in Podgorica, Montenegro. The method analyzed in this paper is the Multi-Criteria Compromise Ranking/Solution (VIKOR), a technique used in multi-criteria optimization for different systems. During the research preparation, six competitive alternatives were established. The ranking of these alternatives was carried out based on four different preference approaches. The primary difference between these approaches lies in the varying weights assigned to certain criteria. Specifically, the weight ratios for individual criteria were adjusted. For the analysis of the building's verticality, a geodetic network design, selected as the optimal compromise solution, was utilized. The network measurements were conducted using appropriate geodetic instrument and supporting equipment. After completing the measurements in the optimized network, the network was adjusted, and the accuracy of the positional coordinates was assessed.

Comparison of selected reliability optimization methods in application to the second order design of geodetic network

Abstract Determination of the precision of the designed observations in a geodetic network referred as the Second Order Design is an essential element of the network design process. Although the precision requirements are usually of key importance, ensuring an adequate level of reliability, understood as the possibility of outliers detection can be also vital. The subject of this study is the optimization of the observations’ precision distribution to get the balanced observation reliability indices. The objective of the work is to test usability of two optimization methods based on optimization algorithms, (simulated annealing and Hooke–Jeeves optimization), to solve the mentioned problem. An analytical method proposed by Amiri-Simkooei was applied as a reference. The performance of the above-mentioned methods was tested on two simulated angular-linear networks. Due to acceptable working time and the possibility of defining the boundary conditions on the final solution, the Hooke–Jeeves method appeared to be the most suitable to solve the analysed problem.

The use of VIKOR Method in Finding the Optimal Solution for a Special-Purpose Geodetic Network Design

This study deals with the use of VIKOR method in finding the optimal solution for a special-purpose geodetic network design. It is about a multi-criteria compromise ranking method developed in 1986. Based on previously defined criteria functions related to precision and reliability, four acceptable alternative solutions were firstly established. Then, with the aim of finding the optimal one, those solutions were subjected to VIKOR method. The geodetic micro-network used in this study was simulated as a trilateration one and consisted of six control points discretizing a structural geometry as well as four, five or six reference points (pillars), depending on what alternative solution it was about. The optimal network design should have ensured the detection of deviations of the control points' positions in accordance with a priori introduced tolerances and constraints. It turned out the approach based on VIKOR method is a very efficient tool in tasks involving multiple conflicting requirements referred to a geodetic engineer and in the cases when the decision must be made in a short term.

МЕТОДИКА ПРОЕКТИРОВАНИЯ И ПОСТРОЕНИЯ ГЕОДЕЗИЧЕСКОЙ СЕТИ ПРИ НАЗЕМНОМ ЛАЗЕРНОМ СКАНИРОВАНИИ КРУПНЫХ ПРОМЫШЛЕННЫХ ОБЪЕКТОВ

When performing terrestrial laser scanning of large industrial facilities, it must give special atten-tion to designing and establishing a geodetic network to datum transformation measurements into a coordinate system. However, the design of geodetic networks by traditional geodesy methods does not consider all the features of the technique of terrestrial laser scanning. Also worth taking into account is the specifics of laser scanning data processing. Therefore, it is necessary to develop a methodology for designing and establishing a geodetic network in the context of terrestrial laser scanning. For this, the article analyzes the features of terrestrial laser scanning of large industrial facilities and methods for measurement results processing. Based on the analysis and practical experience, developing a flow chart for establishing a geodetic network was on the condition that registration of point cloud perform-ing used iterative closest points algorithm and datum transformation coordinate system performing us-ing HDS targets. Also, based on practical experience, the dependence of the values of the root-mean-square error of registration point cloud and the root-mean-square error of laser scanning station posi-tioning on the distance between the stations. As a result, a methodology for designing and establishing the geodetic network has been substantiated, including two stages. The first stage is the design and ac-curacy assessment of the geodetic control network, the coordinates of which are determined from the datum points by traditional geodesy methods. The second stage is the design and accuracy assessment of the laser scanning station positioning, the coordinates of which are determined from the geodetic control network.

New Computer Simulation Method for First-Order Design of Geodetic Network: Aiming for Low Cost

Optimization of a geodetic network is a process in which a specific stage (or stages) is designed in such a way that the obtained result meets the assumed (optimum) design requirements. The goal of this article is to present a new method for designing observation plans first-order design (FOD) that aims at maximally reducing the number of observations (the cost criterion) while maintaining the a priori established quality criteria (accuracy and reliability). To achieve this goal, a categorization of points was introduced and the criteria were arranged into a hierarchy. Because the method uses computer simulation, sequential estimation was also used to speed up the computational process. The cost model is a general model defined as minimization of the number of observations in the network, regardless of their weight. The study was carried out using the example of a geodetic network designed for the National Stadium in Warsaw. The results bear out the effectiveness of reduction of observations and show the impact that strict criteria have on the scale of this reduction.

Control Points Selection Based on Maximum External Reliability for Designing Geodetic Networks

A set of stable and identifiable points—known as control points—are interconnected by direction, distance or height differences measurements form a geodetic network. Geodetic networks are used in various branches of modern science, such as monitoring the man-made structures, analysing the crustal deformation of the Earth, establishing and maintaining a geospatial reference frame, mapping, civil engineering projects and others. One of the most crucial components for ensuring the network quality is Geodetic Network Design. The design of a geodetic network depends on its purpose. In this paper, an automatic procedure for selection of control points is proposed. The goal is to find the optimum control points location so that the maximum influence of an anomaly measurement (outlier) on the coordinates of the network is minimum. Here, the concept of Minimal Detectable Bias defines the size of the outlier and its propagation on the network coordinates is used to describe the external reliability. The proposed procedure was applied to design a levelling network. Two scenarios were investigated: design of a network with one control point (minimally constrained levelling network) and another with two control points (over-constrained levelling network). The centre of the network was the optimum position to set the control point. Results for that network reveal that the centre of the network was the optimum position to set the control point for the minimal constraint case, whereas the over-constraint case were those with less line connections. We highlight that the procedure is a generally applicable method.

Multicriteria Decision Making in Geodetic Network Design

AbstractThe article presents an original approach to the design of geodetic networks, taking into account quality criteria. This approach is based on the geodetic network design using the methods o...

Geodetic network design and data processing for Hong Kong–Zhuhai–Macau link immersed tunnel

The immersed tunnel is composed of elements which are prefabricated elsewhere and floated to the tunnel site to be sunk into the prepared trench. Each element and the closure joint must line up exactly for the watertight gaskets to seal properly. For the construction of extra-long immersed tunnel, particular care should be taken in the perspective of geodetic control. Therefore, the design and implementation of the geodetic basis and hierarchical surface control networks are described. To decrease the influence of lateral refraction and to improve the configuration strength and increase the number of redundant observation compared with traverse, the design of underground surveying network named duo-linear joint chain is presented. The data-processing methodology, including outlier detection for excluding outliers from observation and variance component estimation for realistic precisions of observation, is described. Hong Kong–Zhuhai–Macau immersed tunnel surveying data are analysed and the performance of the geodetic networks and data processing methodology is demonstrated.

Optimization of observation plan based on the stochastic characteristics of the geodetic network

Abstract Optimal design of geodetic network is a basic subject of many engineering projects. An observation plan is a concluding part of the process. Any particular observation within the network has through adjustment a different contribution and impact on values and accuracy characteristics of unknowns. The problem of optimal design can be solved by means of computer simulation. This paper presents a new method of simulation based on sequential estimation of individual observations in a step-by-step manner, by means of the so-called filtering equations. The algorithm aims at satisfying different criteria of accuracy according to various interpretations of the covariance matrix. Apart of them, the optimization criterion is also amount of effort, defined as the minimum number of observations required. A numerical example of a 2-D network is illustrated to view the effectiveness of presented method. The results show decrease of the number of observations by 66% with respect to the not optimized observation plan, which still satisfy the assumed accuracy.

Optimal observational planning of local GPS networks: assessing an analytical method

AbstractPrecision, reliability and cost are the major criteria applied in optimization and design of geodetic networks. The terrestrial networks are being replaced quickly by permanent and campaign Global Positioning System (GPS) networks. These networks must be optimized using the same three criteria. In this article the optimization of the observational plan of local GPS networks (Second Order Design (SOD)) is considered using the precision criterion. This study is limited to the selection of optimal numbers and the best distribution of the non-trivial baselines throughout the network. This objective is accomplished based on the SOD solution through the analytical method in operational research by the means of quadratic programming algorithm. This presented method is tested on a real GPS network and appears to be a useful technique in terms of cost reduction in the field work by the provided observational plan and optimal distribution of the baselines throughout the network. Results indicate that weights of almost 36% of the baselines are negligiblewhen compared to the weights of the rest of the baselines; therefore, they could be eliminated fromthe observational plan, resulting in a 36% saving in the fieldwork cost.

Testing the compatibility of constraints for parameters of a geodetic adjustment model

Geodetic adjustment models are often set up in a way that the model parameters need to fulfil certain constraints. The normalized Lagrange multipliers have been used as a measure of the strength of constraint in such a way that if one of them exceeds in magnitude a certain threshold then the corresponding constraint is likely to be incompatible with the observations and the rest of the constraints. We show that these and similar measures can be deduced as test statistics of a likelihood ratio test of the statistical hypothesis that some constraints are incompatible in the same sense. This has been done before only for special constraints (Teunissen in Optimization and Design of Geodetic Networks, pp. 526–547, 1985). We start from the simplest case, that the full set of constraints is to be tested, and arrive at the advanced case, that each constraint is to be tested individually. Every test is worked out both for a known as well as for an unknown prior variance factor. The corresponding distributions under null and alternative hypotheses are derived. The theory is illustrated by the example of a double levelled line.

Optimized Zero and First Order Design of Micro Geodetic Networks

Precision is one of the main elements that control the quality of a geodetic network, which defines as the measure of the network efficiency in propagation of random errors. This research aims to solve ZOD and FOD problems for a geodetic network using Rosenbrock Method to optimize the geodetic networks by using MATLAB programming language, to find the optimal design of geodetic network with high precision. ZOD problem was applied to a case study network consists of 19 points and 58 designed distances with a priori deviation equal to 5mm, to determine the best points in the network to consider as control points. The results showed that P55 and P73 having the minimum ellipse of error and considered as control points. FOD problem was applied to three cases of selected network to analyzed using the objective function of A-Optimality and D-Optimality, with selected range of movement of 300m to each point in each direction. The first case was a free network, the second case was with P55 and P73 as control points, and the third case was with P42 and P44 as control points. The results showed that the third case was the optimal design with high precision

GPS baseline configuration design based on robustness analysis

AbstractThe robustness analysis results obtained from a Global Positioning System (GPS) network are dramatically influenced by the configurationof the observed baselines. The selection of optimal GPS baselines may allow for a cost effective survey campaign and a sufficiently robustnetwork. Furthermore, using the approach described in this paper, the required number of sessions, the baselines to be observed, and thesignificance levels for statistical testing and robustness analysis can be determined even before the GPS campaign starts. In this study, wepropose a robustness criterion for the optimal design of geodetic networks, and present a very simple and efficient algorithm based on thiscriterion for the selection of optimal GPS baselines. We also show the relationship between the number of sessions and the non-centralityparameter. Finally, a numerical example is given to verify the efficacy of the proposed approach.

Basic Concepts of Optimization and Design of Geodetic Networks

This contribution reviews a few basic concepts of optimization and design of a geodetic network. Proper assessment and analysis of networks is an important task in many geodetic-surveying projects. Appropriate quality-control measures should be defined, and an optimal design should be sought. The quality of a geodetic network is characterized by precision, reliability, and cost. The aim is to present a few case studies that have been designed to meet optimal precision and reliability criteria. Though the case studies may be of interest to the geodetic community in their own right, the aim is to gain insight into the general optimization problem of a geodetic network. This is also potentially of interest for educational purposes. The case studies include a zeroth-order design to improve the precision of the network points in a traverse network and a first-order design to meet the high reliability and maximum precision criteria in a geodetic network. It is shown that not only the configuration of the network but also the type of the observations used can affect the design criteria. For example, the case studies presented show that the optimal shape of the trilateration network (intersection with distances) can result in a weak network in the sense of reliability and precision if the observations are replaced by angles rather than distances (triangulation network). In close relation to the optimization problem of a geodetic network, the global positioning system satellite configuration is also optimized for a particular case that provides the minimum value of the geometric dilution of precision.

Second Order Design of Geodetic Networks by the Simulated Annealing Method

The problem of determining the required precision in observations in order to obtain a desired precision in final parameters, classically known as the second order design problem, is revisited in this paper and proposed to be solved by the simulated annealing method. An example and a flexible implementation in MATLAB are given.

Geodetic Network Design and Optimization on the Active Tuzla Fault (Izmir, Turkey) for Disaster Management.

Both seismological and geodynamic research emphasize that the Aegean Region, which comprises the Hellenic Arc, the Greek mainland and Western Turkey is the most seismically active region in Western Eurasia. The convergence of the Eurasian and African lithospheric plates forces a westward motion on the Anatolian plate relative to the Eurasian one. Western Anatolia is a valuable laboratory for Earth Science research because of its complex geological structure. Izmir is a large city in Turkey with a population of about 2.5 million that is at great risk from big earthquakes. Unfortunately, previous geodynamics studies performed in this region are insufficient or cover large areas instead of specific faults. The Tuzla Fault, which is aligned trending NE–SW between the town of Menderes and Cape Doganbey, is an important fault in terms of seismic activity and its proximity to the city of Izmir. This study aims to perform a large scale investigation focusing on the Tuzla Fault and its vicinity for better understanding of the region's tectonics. In order to investigate the crustal deformation along the Tuzla Fault and Izmir Bay, a geodetic network has been designed and optimizations were performed. This paper suggests a schedule for a crustal deformation monitoring study which includes research on the tectonics of the region, network design and optimization strategies, theory and practice of processing. The study is also open for extension in terms of monitoring different types of fault characteristics. A one-dimensional fault model with two parameters – standard strike-slip model of dislocation theory in an elastic half-space – is formulated in order to determine which sites are suitable for the campaign based geodetic GPS measurements. Geodetic results can be used as a background data for disaster management systems.

Geodetic Network Design and Optimization on the Active Tuzla Fault (Izmir, Turkey) for Disaster Management

Geodetic Network Design and Optimization on the Active Tuzla Fault (Izmir, Turkey) for Disaster Management

Satellite radar interferometry for deformation monitoring: a priori assessment of feasibility and accuracy

Abstracts Conventional satellite repeat-pass radar interferometric measurements can be used for monitoring subsidence phenomena with high accuracies. This methodology was developed for mostly contiguous phase observations, enabling spatial coherence estimation and 2D phase unwrapping. Unfortunately, in many areas in the world, complete temporal decorrelation of the scattering characteristics occurs in a period reaching from days to months. In these circumstances, only urban areas and isolated stable scatterers maintain coherent. The problem is to detect these scatterers amidst their decorrelated neighbors, as spatial coherence estimation is not possible anymore. Methodology for the detection and analysis of such points, labeled permanent scatterers (PS), has been developed by Ferretti et al. [Ferretti, A., Prati, C., Rocca, F., 2000. Nonlinear subsidence rate estimation using permanent scatterers in differential SAR interferometry. IEEE Trans. Geosci. Remote Sens. 38(5), 2202–2212], using many (30 or more) SAR images of a particular site. This approach enables coherence estimation using temporal, pixel-based evaluation. Together, these points form a geodetic network of opportunity with different characteristics when compared to traditional geodetic network design. For practical purposes, it is necessary to define a set of guidelines to assess the feasibility of contiguous or PS radar interferometry for a specific deformation problem. This feasibility is dependent on the number of SAR data acquisitions available, their spatial and temporal baselines and observation statistics, and the expected spatial and temporal behavior of the deformation process. Here, we will discuss the evaluation procedure to assess a priori whether the techniques of contiguous and PS–InSAR are feasible for specific deformation studies in terms of precision and reliability.

A NEW METHOD FOR SECOND ORDER DESIGN OF GEODETIC NETWORKS: AIMING AT HIGH RELIABILITY

The main design criteria for a geodetic network are precision, reliability and strength, and cost. In this paper, a new method for second order design of geodetic networks for high reliability is suggested. In this methodology, the weight of the observations are improved in such a way that the same redundancy numbers are obtained for all observations. The effectiveness of the methodology is verified with two examples.

First-order design of geodetic networks using the simulated annealing method

The general problem of the optimal design for a geodetic network subject to any extrinsic factors, namely the first-order design problem, can be dealt with as a numeric optimization problem. The classic theory of this problem and the optimization methods are revised. Then the innovative use of the simulated annealing method, which has been successfully applied in other fields, is presented for this classical geodetic problem. This method, belonging to iterative heuristic techniques in operational research, uses a thermodynamical analogy to crystalline networks to offer a solution that converges probabilistically to the global optimum. Basic formulation and some examples are studied.