# Bahattin ErdoganYildiz Technical University · Department of Geomatic Enginering

Bahattin Erdogan

PhD

## About

58

Publications

8,671

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293

Citations

Citations since 2017

Introduction

Bahattin Erdogan currently works at the Department of Geomatic Enginering, Yildiz Technical University. Bahattin does research in Deformation Analysis, Accuracy of GNSS Point Positioning and Statistical Analysis.

Additional affiliations

October 2015 - present

May 2012 - October 2015

January 2005 - May 2012

## Publications

Publications (58)

In geodetic studies, Global Positioning System (GPS) is widely preferred since it can be operated day and night and in all weather conditions. Also, GPS is used especially in the studies which require high accuracy such as monitoring deformations and determining tectonic movements. However, GPS error sources must be eliminated to achieve precise po...

The use of unmanned aerial vehicles (UAV) in photogrammetric mapping/surveying facilities has increased recently due to the developments on photogrammetric instruments and algorithms that enhance high-quality final products (orthoimages, digital surface model-DSM, etc.) in fast, accurate, and economical way. The aim of this study was to assess the...

Due to contents of the dry air and water vapor, troposphere affects radio signals of the space geodetic techniques (e.g., GNSS and VLBI) as range delays. These tropospheric delays should be eliminated to achieve precise point positioning. Over the years, researchers have been developed many of troposphere model. However, the existing models differ...

Küresel ısınmaya bağlı olarak gerçekleşen iklim değişimi ve etkilerine yönelik çalışmalar tüm dünyada güncel ve öncelikli hâle gelmiştir. Mevsimsel döngüye göre kar kalınlığı değişimlerinin izlenmesi, karın birikiminin tespit edilmesi ve yüzeyde kalma süresi ile erime hızının belirlenmesi de temel iklim modelleme çalışmaları için önemlidir. Bununla...

In some cases, tests for outliers and robust methods based on the Least Square Estimation (LSE) fail to detect and isolate outliers. LSE 'smears the effect' of an outlier on all estimates of the residuals, the unknowns, and the a posteriori variance of unit weight. Therefore as bias goes to infinity, the Influence Function (IF) also goes to infinit...

Nowadays, Global Navigation Satellite Systems (GNSS) data are used in most of the geodetic studies. Positioning information can be obtained by using GPS, GLONASS, Galileo and BeiDou in the structure of the GNSS. International GNSS Service (IGS) has initiated a project, called Multi-GNSS Experiment (MGEX), to collect, track and analyze different sig...

In Conventional Deformation Analysis (CDA), at least two different epochs are adjusted by using the Least Squares Estimation (LSE) method and compared statistically. The effect of the geometry of the network is an essential part of the adjustment model and the LSE method smears the effects of the displaced point over the other nondisplaced points....

The Global Navigation Satellite System (GNSS) is used for precise positioning applications, such as surveying and geodesy. The aim of the present work is to evaluate the effectiveness of web-based relative positioning (RP) and precise point positioning (PPP) GNSS post-processing services using measurements of different satellite visibility obstacle...

Kinematic Deformation Analysis (KDA) models are preferred to estimate displacement, velocity and acceleration parameters. The quadratic models are often used in KDA. To estimate the reliability of the model, Linear Motion Systems (LMS) integrated with GPS were established at four object points located properly in University Campus. Moreover, five c...

Global positioning system (GPS) refers positioning, timing and navigation services for different engineering applications. GPS positioning accuracies vary depending on the several parameters such as surveying method, data processing strategy and software packages. Bernese v5.2 software package is an important tool for processing and analyzing of th...

Benford’s law (BL), also known as the first-digit or significant-digit law, is an intriguing pattern in data sets, considers the frequency of occurrence of the first digits, which are not uniformly distributed as might be expected, conversely follow a specified theoretical distribution. According to BL, the occurrence of first non-zero digit in a n...

The linear and quadratic kinematic models are frequently preferred to put forth the characteristic of deformations in geodetic applications such as the determination of the tectonic, landslide and engineering structure motions. However, if one uses the linear model, this may result in an incorrect estimation of the velocity or acceleration when the...

Classical outlier detection test methods such as Baarda test and Pope test are generally preferred in geodetic problems. They depend on the Least Square Estimation (LSE) and LSE is very sensitive to the variations of the model. The capacity of the LSE changes depending on the different significance level, different type of outlier, the number of ou...

In different Geodetic networks the observations are measured repetitively. These observations, called original observations, are independent. At the design stage of the deformation monitoring network, either the mean value of the original observations or the original observations may be considered. Conventional Deformation Analysis (CDA) is based o...

Precise Point Positioning (PPP) algorithms have been widely used in the Global Positioning System (GPS)-based applications. A PPP technique with a single receiver provides effective solutions where accurate absolute positioning is required. This paper provides the performance assessment of GPS PPP for detecting the displacements caused by an earthq...

A kinematic deformation analysis (KDA) model is mostly preferred to estimate the displacement, velocity, and acceleration parameters in deformation analysis. Different models, such as linear and quadratic, are used in KDA. The displacement, velocity, and acceleration parameters are generally determined by the least-squares estimation (LSE) method....

In recent years, Precise Point Positioning (PPP) techniques, which are alternative to relative positioning techniques, have begun to be widely used in Global Navigation Satellite System (GNSS) positioning applications. The PPP technique offers an effective solution to obtain coordinates at high accuracy with a single receiver. Real-time PPP (RT-PPP...

Bir
datumdan diğer bir datuma olan koordinat dönüşümü jeodezinin temel
problemlerinden bir tanesidir. Genel olarak problem, matematiksel eşitlikler
kullanarak koordinatların, kartezyen koordinat sisteminde iki eksenin kesişimi
ile tanımlanan bir başlangıç noktasından başka bir sisteme dönüşümü olarak
tanımlanmaktadır. Dönüşüm parametrelerinin hesap...

Efficiency of the Multi-GNSS Precise Point Positioning Solutions

Determination of Snow Depth Using Reflected GPS Signals

In deformation analysis, statistical methods have been used to detect displaced point(s) and to identify the characteristic feature of object with a high of probability. These methods can sometimes have wrong results; that's why the reliability of the method should be known. However; to measure the reliabilities of the methods, it is required to kn...

The usage of the Precise Point Positioning (PPP) technique have increased rapidly in recent years. Also, the free service of the of high precision orbit/clock products and the other important information that are supported by different international organizations make major contributions for applications of the PPP technique as Post Process (PP) an...

Precise Point Positioning (PPP) technique is one of the most important subject in Geomatic Engineering. PPP technique needs only one GNSS receiver and users have preferred it instead of traditional relative positioning technique for several applications. Scientific software has been used for PPP solutions and the software may underestimate the form...

In recent years, users prefer Global Navigation Satellite System (GNSS) technique rather than traditional techniques for geodetic applications. Accuracy of GNNS observations depends on several parameters such as surveying method, data processing strategy and software. GNSS observations are generally processed by using academic software or commercia...

Benford’s law (BL), also known as the First-digit or Significant-digit law, is an intriguing pattern in data sets, considers the frequency of occurrence of the first digits, which are not uniformly distributed as might be expected, conversely follow a specified theoretical -logarithmic- distribution. In BL, the first leading (i.e. first non-zero) d...

Deformation analysis conventionally depends on the comparison of coordinate differences between different observation epochs. If the coordinates’ differences are statistically confirmed, then the changes in point coordinates are interpreted as the displacement. At the first step, global congruency test is applied and if H0 hypothesis is rejected th...

Jeodezik ağlarda ölçü kümesi içerisindeki kaba
hatalar, kestirilen parametreler ve bunlara ait standart
sapmalar açısından bozucu etkiye sahiptirler. Bu etkileri
azaltmak ya da elimine etmek amacıyla genellikle
Baarda ve Pope test yöntemleri (klasik uyuşumsuz ölçü
yakalama yöntemleri) kullanılmaktadır. Jeodezik
ağlarda ölçüler (uzunluk, doğrultu, y...

In recent years, due to the increase in providers of orbit and clock corrections of satellites for data evaluation in real-time and post-processing the method of Precise Point Positioning (PPP) using measurements of Global Navigation Satellite System (GNSS) and Web-based online positioning services have become widespread. Owing to some advantages,...

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 networ...

Nowadays, Precise Point Positioning (PPP) technique, which is alternative to relative positioning depending on the Global Navigation Satellite System (GNSS), has been extensively preferred. PPP technique make possible to estimate high precise point coordinates only using one single receiver. In addition, Real Time PPP (RT-PPP) solutions are perform...

The accuracy of GNSS positioning varies depending on the observing methods. The accuracy of static GNSS positioning is approximately millimeters but the accuracy is approximately centimeters for rapid static positioning. When the required accuracy cannot be obtained in rapid static GNSS positioning, increasing the observing session duration could p...

Coordinate transformation is an important problem in geodesy discipline. Variations in stochastic and functional models in transformation problem cause different estimation results. Least-squares (LS) method is generally implemented to solve this problem. LS method accepts only one epoch coordinate data group erroneous in stochastic model. But howe...

Outlier detection is an important task for fitting a model to a set of data. Two different outlier detection approaches are given as tests for outliers and robust methods. For these approaches, usually outliers are considered as additive bias terms neglected in the original adjustment model. However, there is another approach that outlier is consid...

Deformation analysis plays an important role for human life safety; hence investigating the reliability of the obtained results from deformation analysis is crucial. The deformation monitoring network is established and the observations are analyzed periodically. The main problem in the deformation analysis is that if there is more than one displac...

The observations in geodetic networks are measured repetitively and in the network adjustment step, the mean values of these original observations are used. The mean operator is a kind of Least Square Estimation (LSE). LSE provides optimal results when random errors are normally distributed. If one of the original repetitive observations has outlie...

In geodetic networks, observations are measured repetitively, and the mean values of these observations are used for network adjustment, outlier detection, deformation analysis, etc. These repetitive observations are independent, and if one of them has outlier, the effect of the outlier decreases depending on the computed mean value. Also, the mean...

Deformation analysis plays an important role for human safety, so investigating the reliability of the obtained results from deformation analysis is extraordinarily important. It uses statistics most widely and if H-0 hypothesis is rejected in applying of the global congruency test, the localisation process is performed to detect one or more displa...

In geodetic measurements some outliers may occur sometimes in data sets, depending on different reasons. There are two main approaches to detect outliers as Tests for outliers (Baarda's and Pope's Tests) and robust methods (Danish method, Huber method etc.). These methods use the Least Squares Estimation (LSE). The outliers affect the LSE results,...

Nowadays, Global Positioning System (GPS) has been used effectively in several engineering applications for the survey purposes by multiple disciplines. Web-based online services developed by several organizations; which are user friendly, unlimited and most of them are free; have become a significant alternative against the high-cost scientific an...

To monitor plate tectonics, the movement of engineering structures, landslides etc., geodetic control networks as, e.g., conventional vertical, horizontal or 3D networks as well as GPS networks, may be established. It is necessary to control the stability of these networks periodically. The main aim of geodetic deformation measurements is to identi...

The main problem in conventional deformation analysis (CDA) is that if there is more than one displaced point in a given monitoring network, the least-squares estimation (LSE) smears the disturbing effects of the displaced points over all other points. Therefore, only one displaced point can be detected successfully using CDA. If the number of disp...

Outliers in observation set badly affect all the estimated unknown parameters and residuals, that is because outlier detection has a great importance for reliable estimation results. Tests for outliers (e.g. Baarda's and Pope's tests) are frequently used to detect outliers in geodetic applications. In order to reduce the computational time, sometim...

In geodetic networks, probable failures in the outlier detection arise not only due to ability of outlier detection methods, but also due to the weakness in the configuration of the networks. The purpose of this paper is to detect this weakness by cross-checking the observations for existing geodetic networks or at design stage. To do it, we introd...

Outliers in geodetic networks badly affect all parameters and their variances estimated by least-squares. Tests for outliers (e.g. Baarda’s and Pope’s tests) are frequently used to detect outliers in geodetic networks. To measure the ability of these tests, the mean success rate (MSR) is proposed. Studies have shown that the MSRs of these tests in...

Rapid static GPS positioning is an alternative to real time kinematic (RTK) GPS positioning or to static GPS positioning. With careful attention, one can obtain cm positioning using the method. Rapid static GPS has become popular through online rapid static GPS positioning services that emerged only recently. Then researchers have studied the accur...

In deformation analysis, it is important to know whether the points detected by conventional deformation analysis (CDA) are really displaced or not, and also if there are any more displaced points in the network. It is impossible to answer these questions unless the actual positions of the displaced points before the analysis are known. Moreover, t...

Rapid static GPS is used in practical surveying applications and in monitoring of various natural hazards such as land slides. The technique emerged as a surveying tool that provides cm positioning in which the ambiguity resolution is obtained in minutes taking the advantage of various statistics and using special algorithms. It is still tempting t...

Deformation analysis is one of the most interest areas in the survey engineering. Deformation analysis contains the comparison of coordinate differences between different observation epochs. If the coordinates’ differences statistically are confirmed, the point coordinates changes are interpreted as the displacement. Several deformation models can...

Deformation analysis is one of the most interest areas in the survey engineering. There are two kinds of network in deformation analysis, relative monitoring network and absolute monitoring network. In this study, we investigate reliability of the relative deformation networks with the conventional deformation analysis techniques using Monte Carlo...

## Projects

Projects (2)

GNSS-IR yöntemine dayalı olarak sinyal gürültü oranı (signal-to-noise ratio, SNR) verileriyle kar kalınlığı değişimlerini belirlemek, GNSS-IR kestirimlerini iyileştirmek için yeni modeller geliştirmek, farklı filtreler ve istatistiksel analiz yöntemleri kullanarak en uygun stratejiyi ortaya koymak.

Bu projede Kinematik Deformasyon Analizi ile kestirilen farklı modellerin sonuçlarının güvenilirliğinin ölçülmesi ve sonuçların tartışılması amaçlanmıştır. (In this project, it is aimed to measure the reliability of the results of different models estimated by Kinematic Deformation Analysis and to discuss the results.)