Cemal Ozer YigitGebze Technical University | GYTE · Department of Geomatics
Cemal Ozer Yigit
PhD
About
89
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Introduction
I currently work at Gebze Technical University in Gebze/Turkey. I have been working on High-rate GNSS methods, such as RTK, PPP, and their application to structural health monitoring, natural hazard and earthquake early warning, and crustal deformation.
Additional affiliations
July 2018 - August 2019
April 2015 - June 2018
June 2008 - June 2009
University of New South Wales
Position
- Visiting Academic
Publications
Publications (89)
Relative/network GPS/GNSS (Global Positioning System/Global Navigation Satellite System) positioning has been widely used to precisely measure both structural and crustal deformation monitoring for more than two decades ago. In recent years, interest has increased for PPP (Precise Point Positioning) method due to its capability to generate position...
The fundamental dynamic property of the structures is the oscillation frequency, which can be derived from the response measurements. The structures with a short/medium/long span (e.g. suspended or cable bridges) vibrate vertically rather than horizontally. The potential of GNSS precise point positioning (PPP) for detecting the dynamic response of...
This paper investigates the usability of Global Navigation Satellite System (GNSS) Precise Point Positioning (PPP) methods, traditional PPP with a float-ambiguity solution and with ambiguity resolution (PPP-AR), in structural health monitoring applications based on experimental tests using a single-axis shake table. To evaluate the performance of t...
Skyscrapers cause both limited sky-view and multipath error when using Global Navigation Satellite System (GNSS) measurements for monitoring structural movements. To reduce multipath errors, cut-off elevation angle can be set to a high value such as 30°−40°. However, in the case of employing high cut-off elevation angles, the use of GPS only may no...
The use of final IGS precise orbit and clock products for high-rate GNSS-PPP proved its effectiveness in capturing dynamic displacement of engineering structures caused by earthquakes. However, the main drawback of using the final products is that they are available after approximately two weeks of data collection, which is not suitable for timely...
In this study, the global navigation satellite system (GNSS) high-rate data of 162 stations during the February 6, 2023, Kahramanmaraş earthquake sequence (Mw: 7.8 and Mw: 7.6) were evaluated with Precise Point Positioning (PPP) method. Co-seismic displacement time series of each of the GNSS stations during the earthquake sequence were generated. T...
A geodetic levelling staff, a method for measuring a height with the geodetic levelling staff, and a system including the geodetic levelling staff and a level are provided. The geodetic levelling staff includes a circular level that indicates whether the geodetic levelling staff is in a vertical position, a level detection unit for detecting a bubb...
Bu çalışma düşük maliyetli GNSS (Global Navigation Satellite System) alıcı ve anteninden elde edilen SF (tek frekanslı) çoklu GNSS gözlemlerine dayalı VA (varyometrik yaklaşım) tekniğinin düşey yönlü dinamik davranışları belirleyebilme yeteneğini değerlendirmektedir. Bu amaçla, düşey yönlü dinamik davranışları simüle edebilen bir sarsma tablası ile...
This study presents the capability of the single-frequency (SF) variometric approach (VA) technique with low-cost GNSS observations to detect short-term dynamic behaviors. Harmonic oscillations with amplitudes between 5 and 20 mm and frequencies between 0.3 and 5.0 Hz were generated employing a single-axis shake table to investigate the performance...
This contribution presents an evaluation of the effectiveness of the low-cost GNSS technique in structural health monitoring and GNSS-seismology applications. To evaluate the ability of the low-cost GNSS technique, harmonic oscillation, and earthquake tests were carried out employing the ZED-F9P-02B OEM low-cost GNSS receiver and two low-cost anten...
This contribution presents an evaluation of the positioning ability of the real-time (RT) ionosphere-free (IF) single-frequency precise point positioning (SF-PPP) technique in Arctic and Antarctic under different auroral activities. Firstly, Global Positioning System (GPS)-only observations obtained from International GNSS Service (IGS) stations in...
This study presents the usability of the high-rate single-frequency Precise Point Positioning (SF-PPP) technique
based on 20 Hz Global Positioning Systems (GPS)-only observations in detecting dynamic motions. SF-PPP solutions were
obtained from post-mission and real-time GNSS corrections. These include the International GNSS Service (IGS)-Final, IG...
Variometric approach (VA) technique has been introduced as an alternative to real-time kinematics and real-time precise point positioning techniques. As the ability of the variometric approach to detect short-term dynamic behaviors in real-time mode in applications such as Global Navigation Satellite Systems (GNSS)-seismology and structural health...
We combine accelerometer and asynchronous high-rate GNSS data to retrieve dynamic displacements. The method adopts relative GNSS positioning with observations of different sampling rates at rover and reference stations. The objective is to examine the feasibility of downsampling GNSS data at reference stations and thus, verify whether permanent GNS...
Havran-Balıkesir Fay Zonu (HBFZ), Batı Anadolu’daki önemli fay zonlarından birisidir. Edremit’in doğusundan, Balıkesir’e kadar KKD–GGB yönünde uzanan HBFZ iki ana fay ve altı segmentten oluşmaktadır. Fay zonu üzerinde kapsamlı paleosismolojik çalışmalar gerçekleştirilmiş ve zonun segmentlerindeki depremsizlik süreleri sismik bir boşluk (asismik har...
Bu çalışmada 6 Şubat 2023 tarihinde sırasıyla yerel saat ile 04:17 ve 13:24’te artarda meydana gelen Sofalaca-Şehitkamil Gaziantep (Mw:7.7) ve Ekinözü Kahramanmaraş (Mw:7.6) depremlerinin öncül jeodezik sonuçları verilmiştir. Öncül jeodezik sonuçları elde etmek için deprem odak merkezleri etrafındaki ve etkili olduğu alandaki TUSAGA-Aktif istasyonl...
We present the performance of real-time (RT)-precise point positioning (PPP) and GNSS-based variometric approach for displacement analysis stand-alone engine (VADASE) methods in capturing dynamic motions in real time. To examine the effectiveness of the two RT methods, different cases, including harmonic motions in various frequency and amplitude r...
Although the traditional-Precise Point Positioning (PPP) technique, may provide a positioning as precise as the relative positioning technique in long-term observation durations since it has the inability to provide high-precise positioning due to ambiguity problem in short-term observations, the interest in the PPP-AR (Ambiguity Resolution) techni...
In this research, the aim was to examine the aseismic surface deformations that occurred in the Bolvadin district center with a precise leveling technique. For this purpose, a geodetic leveling network consisting of eight profiles and 81 benchmarks was installed in the region, and five campaigns of precise leveling measurements were performed betwe...
Bu çalışma geleneksel-PPP (Precise Point Positioning) ve PPP-AR (Ambiguity Resolution) yöntemlerinin yapı sağlığı izlemeleri ve Global Navigation Satellite Systems (GNSS)-sismolojisi uygulamalarındaki etkinliğini ve ilgili tekniklere çoklu-GNSS gözlemlerinin katkısını araştırmaktadır. Yöntemlerin performanslarını değerlendirmek için yatay yönde har...
Aseismic dip-slip normal fault displacement related to numerous fast-slipping active faults was recently observed in several localities in the western Anatolia extensional province. Still, the characteristics of displacements along with the behavior of individual fault segments are poorly known. Here we analyze an aseismically active normal fault a...
Real-time displacement monitoring of earth crust and engineering structures with the Global Navigation Satellite System (GNSS) is highly important for detecting and preventing the damage and possible loss of life during natural phenomena. Nowadays, the Real-Time Kinematic Precise Point Positioning (RT-PPP) method using a stand-alone GNSS receiver c...
Yeryüzünde meydana gelen dinamik hareketlerin tespit edilmesinde GNSS (Global Navigation Satellite System) sensörüne dayalı birçok konum belirleme yöntemi (Bağıl Kinematik, Gerçek Zamanlı Kinematik (RTK), Hassas Nokta Konumlama (PPP), Gerçek Zamanlı (RT)-PPP vb.) kullanılmıştır. Kullanılan bu yöntemler ikinci bir GNSS alıcısı, internet bağlantısı,...
Nowadays, with the developments in GNSS (Global Navigation Satellite System) technology, the data storage and data processing capacity of GPS (Global Positioning System) receivers has been gradually increased. This situation is widely used in the detection and monitoring of horizontal and vertical vibrations that occur in the structure when high te...
Thanks to advances in receiver and software technology, the high-rate GPS (Global Positioning System) technique has become very important in monitoring the dynamic behavior of man-made structures in both real-time and post-missions. Real-time monitoring of the changes in the behavior of structures due to effects such as natural disasters, wind effe...
Real-time monitoring and the rapid risk assessment of the engineering structures after a natural event is crucial to prevent further disasters. Global Navigation Satellite System (GNSS) relative positioning and Precise Point Positioning (PPP) have been widely used in determining the seismic waveform and structural displacement. On the other hand, v...
In this study, 15 consecutive days of GPS/Galileo observations of three different International GNSS Service (IGS) stations selected at different latitudes were used, and these observations were evaluated in static mode using both traditional-PPP and PPP-AR techniques. In order to evaluate the effect of short and long observation duration on discus...
A high-precision GNSS receiver is a powerful and complementary sensor for early warning and rapid hazard assessment. The developments in GNSS receiver and algorithm provide a broad range of new applications for geosciences and structural engineering investigations in both real-time and post-mission mode. High-rate GNSS has been widely used for high...
Nowadays, the high rate GNSS (Global Navigation Satellite Systems) positioning methods have been widely used as a complementary tool to other geotechnical sensors, such as accelerometer, seismometer, and inertial measurement unit (IMU), to evaluate dynamic displacement responses of engineering structures. However, the most common problem in structu...
Positioning information using PPP (Precise Posint Positioning) method can be obtained with a single GNSS (Global Navigationing Satellite Systems) receiver in both static and kinematic mode at a level very similar to the Relative Positioning method. This method has been used as an alternative to the relative method in recent years since it provides...
This study evaluates the performance of the Precise Point Positioning method using Global Navigation Satellite System measurements (GNSS-PPP) for monitoring vibration modes of shear type buildings excited by harmonic ground motions and hammer tests. For experimental testing, the shear type lumped-mass building system is represented by a specially d...
In the actively deforming region of western Anatolia, crustal deformation is accommodated by destructive earthquakes and a variety of aseismic events. In this study, we investigated the 2016–2017 aseismic sequence located in the Bolvadin Fault, one of the segments of the Akşehir-Simav Fault System of western Anatolia by analysing surface deformatio...
In our study, the positioning accuracy performance of the improved PPP-AR undifferenced single receiver technique, which should allow for more accurate results and faster convergence than PPP-float, is evaluated through a long-period kinematic test in one of the most difficult marine environments: Antarctica. The kinematic experiment was carried ou...
Besides the classical geodetic methods, GPS (Global Positioning System) based positioning methods are widely used for monitoring crustal, structural, ground etc., deformations in recent years. Currently, two main GPS positioning methods are used: Relative and Precise Point Positioning (PPP) methods. It is crucial to know which amount of displacemen...
This study aims at the investigation of using the Precise Point Positioning-Global
Navigation Satellite System (PPP-GNSS) to determine the dynamic characteristics of structures.
A cantilever steel bars having lengths of 70, 100 and 120 cm were tested under dynamic
excitation. The GNSS was used to measure the natural frequencies and damping values o...
This study evaluates the usability of the GNSS-PPP method for structural health monitoring and seismogeodesy applications. Two test scenarios were considered. The first test scenario included monitoring hormonic oscillations in amplitude of 5 mm to 20 mm with the frequency range of 0.2 Hz to 2.5 Hz that were generated using a shaking table, which h...
Recently, the high rate global navigation satellite system-precise point positioning (GNSS-PPP) technique has been used to detect the dynamic behavior of structures. This study aimed to increase the accuracy of the extraction oscillation properties of structural movements based on the high-rate (10 Hz) GNSS-PPP monitoring
technique. A developmental...
Aksehir-Sultandagi Fault Zone (ASFZ) is one of the most important seismogenic zones located in the expansion region of Western Anatolia.
Every man-made structure creates certain risks — dams are no exception. Most failures in man-made structures that have occurred could have been avoided if the structures’ behaviour had been inspected, monitored, and analyzed continuously, and if proper corrective measures had been taken in a timely fashion. The DSI (The General Directorate of State...
Greek-Turkish boundary near the cities Kos and Bodrum has been shaken on July 20, 2017 by a Mw6.6 earthquake. The mainshock is located offshore and did not generate an on-land surface rupture. Analyzing pre- and post-earthquake continuous/survey-type static GPS observations, we investigated co-seismic surface displacements at 20 sites to characteri...
Son yıllarda, Afyon-Akşehir Grabeni'nin orta bölümünde yer alan Bolvadin yerleşim alanı içerisinde, Bolvadin Fayı üzerinde, yıkıcı bir deprem olmaksızın faya paralel/yarıparalel gidişli daha önceden olmayan yüzey deformasyonları oluşmuş ve oluşmaya devam ettiği gözlenmiştir. Çizgisel gidişli yarık ve çatlaklar şeklinde gözlenen yüzey deformasyonlar...
ÖZET: Akşehir-Simav Fay Sistemi (ASFS), Kuzeybatı-Güneydoğu (KB-GD) gidişli olan çok sayıda süreksiz aktif normal fay zonların bulunduğu ve Batı Anadolu Genişleme Bölgesi içerisinde yeralan sismojenik kuşaklardan birisi olan içermektedir. Bölgede son yüzyıl içerisinde yüzey kırığı oluşturmuş çok sayıda deprem meydana gelmiştir. Son yıllarda, Afyon-...
This paper offers a comprehensive assessment of network-based positioning results using GPS-only and combined GPS/GLONASS data under open to limited sky view conditions. Data analysis is performed in a short (4 h) and a long (24 h) term spanning observations from five GNSS stations using 10°, 20°, 30° and 40° elevation cut-off angles, which simulat...
Since the 1990s, seismic deformations have been commonly determined using the Global Navigation Satellite System (GNSS). Recently, the GNSS systems have become even more powerful with the use of new technologies in innovative studies. In this study, the GNSS data was used to investigate interseismic, coseismic and postseismic deformation and veloci...
This paper studies the structural behavior of the Ermenek arch dam, the second highest dam in Turkey. The
investigated period covers the stage of the last-quarter part of first filling (1 and 1/2 year) and the begging of its operational lifetime (1 year). Displacement responses of the dam to temperature load and water load are assessed in detail ba...
In order to produce an accurate noise map of a city or a region, it is necessary to make noise measurements
at certain locations and these measurements must be modeled with the most suitable mathematical
algorithm. A homogeneous and representative distribution of the noise measurement points is the
first key factor in the production of sound noise...
Batı Anadolu Genişleme Bölgesi içerisinde yeralan ve en önemli sismojenik kuşaklardan birisi olan Akşehir-Simav Fay Sistemi (ASFS), Kuzeybatı-Güneydoğu (KB-GD) gidişli olan çok sayıda süreksiz aktif normal fay zonları içermektedir. Tarihsel ve aletsel dönemdeki deprem kayıtları bu sistem içerisinde yüzey kırığı oluşturmuş çok sayıda depremin varlığ...
Batı Anadolu Genişleme Bölgesi içerisinde yer alan ve en önemli sismojenik kuşaklardan birisi olan Akşehir-Simav Fay Sistemi (ASFS), Kuzeybatı-Güneydoğu (KBGD) gidişli olan çok sayıda süreksiz aktif normal fay zonları içermektedir. Tarihsel ve aletsel dönemdeki deprem kayıtları bu sistem içerisinde yüzey kırığı oluşturmuş olan çok sayıda depremin v...
Landslide area occurs on steep-slope and forestry. Generally, investigations are pursuing on the difficult topographical area for monitoring a landslide. GNSS measurements and analysis are providing very accurate, large content, scope and reliable information to monitoring movements on ground surface. Most techniques are not possible produce safe r...
Bu makalede, Hassas Nokta Konumlama (Precise Point Positioning - PPP) yönteminin yüksek duyarlıklı konum bilgisi gerektiren çalışmalarda ölçü süresine bağlı konum belirleme performansının hem GPS ölçüleri hem de GPS/GLONASS ölçüleri kullanılarak araştırılması hedeflenmiştir. Bu amaçla, düşük (ekvator), orta ve yüksek (kutup) enlem olmak üzere 3 far...
Son yıllarda PPP (Precise Point Positioning) yöntemiyle konum belirleme doğruluğunun artması yönteme olan ilginin artmasına ve yöntemin daha yaygın kullanılır hale gelmesine neden olmuştur. CSRS-PPP (The Canadian Spatial Reference System-PPP), APPS (Automatic Precise Positioning Service) v.b. gibi Web-Tabanlı PPP yazılımlarla tek nokta GNSS veriler...
The present study evaluates the dynamic behaviour of the Ermenek Dam, the second highest dam in Turkey, based on conventional geodetic measurements and Finite Element Model (FEM) analyses during its first filling period. In total, eight periods of measured deformation are considered from the end of construction until the reservoir reached its full...
GNSS technology has been extensively used to measure crustal deformation and widely used to construct displacement waveforms. GNSS seismology uses GNSS receiver as displacement seismometer for earthquake studies. In other words, it can sense large dynamic displacement without saturation. In GNSS, relative positioning method requires a reference sta...
Monitoring the response of engineering structures, such as tall buildings, tower and large-scale bridges, under severe loading conditions, such as strong earthquake or wind storm, is an important requirement to verify their design and construction and to evaluate structural condition and reliability. In the last two decades, high-rate real-time or...
In recent years, in addition to the GPS constellation, the ability to utilise extra satellites available in the GLONASS system enhanced the capabilities and possible applications of precise point positioning (PPP) method. However, the intrinsic differences in GPS and GLONASS and the lack of a fully tested global tracking network of multi-GNSS syste...
Ionosphere modeling has been a highly interesting subject within the scientific community due to its effects on the propagation of electromagnetic waves. Propagation of electromagnetic waves is affected by the electron density in the ionosphere. This electron density is not permanent and it can represent regular and irregular variation according to...
Bu çalışmada tek GNSS alıcısı ve geliştirilen kinematik model çözümüne dayalı yüksek frekanslı yapısal titreşimlerin belirlenebilirliği araştırılmıştır. Bu amaçla, esnek ve tek yönlü salınım yapan bir çubuk üzerinde monte edilmiş GNSS alıcısı ile üretilmiş 2 farklı titreşim veri seti kullanılmıştır. Titreşim deneyleri hem birinci mod hem de ikinci...
SUMMARY Detail measurement is one of the most important studies of the survey engineering. It can be defined as the measurement of detail points with sufficient accuracy in order to draw all the natural and artificial objects on the land. About a 20 ha test area were established in Selcuk University Campus to compare RTK-GPS and classic methods. De...
Son yıllarda PPP(Precise Point Positioning) yöntemi araştırmacıların ilgisini çeker hale gelmiştir. PPP yönteminde ikinci bir alıcıya gereksinim olmadan noktanın konumu rahatlıkla cm mertebesinde belirlenebilmektedir. Günümüzde PPP ile konum belirleme hizmeti veren web tabanlı birçok GNSS yazılımı mevcuttur. Bu çalışmada farklı enlem bölgelerinden...
Gebze Yüksek Teknoloji Enstitüsü, Müh. Fak., Jeodezi ve Fotog. Müh. Blm., Gebze-(cyigit,m.yildiz)@gyte.edu.tr ANAHTAR KELİMELER: Ortofoto, planimetrik doğruluk, hava fotoğrafı, GPS/IMU Bu çalışmada, dış yöneltme parametreleri GPS/IMU ile doğrudan coğrafi konumlandırma ve GPS/IMU verileri ile blok köşelerinde ve blok içerisine homojen dağılmış Yer K...
In recent years thanks to modernization of GLONASS, especially increasement of the satellite number, it becomes worthwhile to investigate the usability of GLONASS on global
positioning in terms of accuracy and precision. Many researches have been performed for
investigating the GPS and GLONASS positioning performance. These researches mostly
consis...
Mapping of the ionosphere is a very interesting subject within the scientific community due to its effects on various areas. Many studies have been performed for ionosphere mapping. In recent years GPS observations are widely used for this purpose. This paper demonstrates concept and practical examples of instantaneous mapping of the ionosphere, ba...
Nowadays, GPS is the best positioning system with its constellation, but number of GLONASS satellites increased to the required number, with launched new ones, for positioning. With recent revitalization of GLONASS, a great number of high precision GLONASS and GPS/GLONASS receivers have been produced. In this paper, baselines of two networks have b...
The selection of the optimal GPS baselines can be performed by solving the geodetic second-order design (SOD) problem. In this paper, the particle swarm optimisation (PSO) algorithm, a stochastic global optimisation method, has been employed for the selection of the optimal GPS baselines to be measured in the field that will meet the postulated cri...
As it is known, GLONASS can be used together with GPS on global positioning. Beginning from January 2010, with increasement of GLONASS satellite number and replacement of GLONASS-M satellites with old ones, usability of only-GLONASS became wortwhile. In this study, different length of 3 baselines(long, medium and short) have been processed by using...
Mühendislik yapıları beklenen hizmet ve yaşam süreleri boyunca maruz kalacakları olası yükleri karşılayabilecek şekilde tasarlanır ve inşa edilirler. Kule, gökdelen vb. yüksek yapıların tasarımında, az katlı yapıların aksine, yapıya dinamik yük olarak etkiyen depre-min yanısıra, rüzgar yüklerinin de göz önüne alınması gereklidir. Yapıların rüzgar y...
It is necessary to use different sensors in an integrated manner – GPS, accelerometer, inclina-tion sensor and so on – in order to monitor and identify static, quasi-static and resonant response of tall buildings subjected to wind loading. There are some di¤erences among these sensors with respect to data sampling rate, data quality, and their mea-...
Wind-induced response of tall buildings consists of three components: static, quasi-static and
resonant. It is necessary to use different sensors in an integrated manner – GPS,
accelerometer, inclination sensor and so on – in order to monitor and identify these three
components. There are some differences among these sensors with respect to data sa...
The weight problem in geodetic networks can be dealt with as an
optimization procedure. This classic problem of geodetic network
optimization is also known as second-order design. The basic principles
of geodetic network optimization are reviewed. Then the particle swarm
optimization (PSO) algorithm is applied to a geodetic levelling network
in ord...