Aydın Üstün- PhD
- Professor at Kocaeli University
Aydın Üstün
- PhD
- Professor at Kocaeli University
About
67
Publications
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546
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Introduction
Current institution
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March 2003 - June 2014
Publications
Publications (67)
This study focuses on analysing the impact of deterministic modifications of the Stokes kernel and terrain correction methods for precise geoid determination using the Stokes-Helmert method over a sophisticated topography. Three deterministic modification methods of Stokes’s kernel (Wong-Gore, Vaníček-Kleusberg, and Featherstone-Evans-Olliver) are...
With the progress in Global Navigation Satellite Systems (GNSS) technology, accurate geoid modelling has started to play an essential role in geodetic applications such as establishing height datum as a continuous surface model and related vertical control for infrastructure projects. Thus, numerous geoid modelling methods have been offered since 1...
Jeoit belirleme çalışmalarında 1 santimetre doğruluklu jeoit modeli oluşturmak ana hedeftir. Bu hedefin en hızlı ve en pratik şekilde çözülmesi bazı mühendislik problemlerinin çözülmesini kolaylaştırmaktadır. Bu nedenle jeoit belirmek için kullanılan yöntemler gün geçtikçe geliştirilmektedir. Stokes-Helmert yaklaşımı klasik jeoit modelleme seçenekl...
An efficient algorithm, tc-cylinder, has been developed to obtain terrain corrections by considering computational efficiency, data storage and use, spherical curvature effects, water bodies, etc. High resolution Digital Elevation Models (DEMs) are fundamental data sources for accurate terrain corrections. But a high-resolution DEM like SRTM1 poses...
Today’s geodetic community starts to model an accurate gravimetric geoid within a 5 mm level, which entirely meets the demands of all technical and geoscientific studies. In this context, a wide range of geoid modelling methods have been published through the years, each of them has its own philosophy. Recently, a new geoid modelling technique has...
2017 yılı Aralık ayından itibaren KOÜ Harita Mühendisliği Bölümü’nün yürütücülüğü ve Kocaeli Büyükşehir Belediyesi’nin desteği ile “Çok Bandlı InSAR ve GNSS Tekniği ile Doğu Marmara (İzmit Körfezi) Düşey Yönlü Yer Değiştirmelerin İzlenmesi, Zemin Çökmeleri ile Bina Yoğunluğu ve Sıvılaşma İlişkisinin Araştırılması” başlıklı ve 117Y155 numaralı TÜBİT...
Gravite alanının modellenmesi ile ilgili yapılan son
çalışmalar, topoğrafik kitlelerin etkisi hakkında
güvenilir bilginin önemini ortaya koymaktadır. Yerel
yoğunluk ve topoğrafyanın geometrisi, Newton integrali
tarafından tanımlanan bu etkinin temel bileşenleridir.
Yüksek çözünürlüklü topoğrafya, on yıldan fazla bir
süredir uydu radarından veya hav...
Investigation of systematic errors in GRACE temporal gravity field solutions using the Improved Energy Balance Approach
Land subsidence is a hazard that can severely threaten human life and urban infrastructure. The increase of the construction and floor concentration in the endurable and high liquefaction potential alluvial fields over time is seen as one of the main factors that raise the possibility of ground deformation. Therefore, it is of great importance to m...
Due to complicated geological and hydrogeological configuration, the land of Turkey is affected by variety of dangerous land movements. Slopes after strong earthquake or heavy rain are prone to landslide activity, dry land affected by intensive (and often illegal) water extraction undergoes gradual or sudden subsidence. To assist experts in predict...
Izmit Bay, tectonically, under control of the strike slip North Anatolian Fault System (NAFS) is a depression basin bounded by Kocaeli Peneplain in the north and Samanlı Mountains in the south. After the big earthquake, Mw=7.4 in 1999, many geodetic and geophysical research projects have focused on the monitoring of the post-seismic and inter-seism...
Multipath, a highly autocorrelated signal is observable phenomena during time periods longer than the sidereal period of Global Positioning System (GPS) satellites in their constellations. Multipath pattern and sidereal repeat time interaction are examined in terms of time series correlations of topocentric coordinates using GPS code and phase obse...
In this paper, a control survey to reveal horizontal and vertical deformation development of 8 years in İzmit Bay is presented. The study is a part of ongoing research project focusing on an investigation of subsidence occurrences caused by liquefaction and urbanization in İzmit Bay (the East Marmara). The space geodetic and remote sensing techniqu...
Gravity-related studies (determination of orthometric heights, geoid modelling, gravity reduction, and lateral density changes of topographical masses etc.) require high resolution digital terrain models. High frequency topographical data lead to accurate gravity field solutions. In a rough topography Bouguer plate may induce terrain correction err...
In the not very distant past, many organisations began providing online GNSS data-processing services. Some of these services work on the differential positioning principle and some use precise point positioning. Moreover, these services provide the results for both static and kinematic modes – users only need to specify the mode of processing. In...
Yükseklik belirlemede kullanılan başlıca yöntemler geometrik, gravimetrik ve astrojeodezik nivelmandır. Son iki teknik GPS nivelmanı ile ilişkili yöntemlerdir. Mühendislik ölçmelerinde zaman, maliyet ve doğruluk ilişkisinin optimum olması istenir. Yükseklik ölçmelerinde bunu sağlamak için işin türüne göre farklı yöntemler seçilebilir. Örneğin doğru...
This brief study introduces a partially working concept being developed at IT4Innovations supercomputer (HPC) facility. This concept consists of several modules that form a whole body of an efficient system for observation of terrain or objects displacements using satellite SAR interferometry (InSAR). A metadata database helps to locate data stored...
This brief study introduces a partially working concept being developed at IT4Innovations supercomputer (HPC) facility. This concept consists of several modules that form a whole body of an efficient system for observation of terrain or objects displacements using satellite SAR interferometry (InSAR). A metadata database helps to locate data stored...
It is investigated to what extent EGM96 affects the accuracy of digital elevation model (DEM) produced from the shuttle radar topography mission (SRTM). Global and regional analysis of EGM96 compared with EGM2008 indicate that locally there are large differences distorting to the accuracy level of SRTM DEM. In the absolute sense, the overall geoid...
The current state of work demonstrated in this paper is maps of the spatial and temporal patterns of deformation at ground subsidence by using advanced InSAR methods at specific areas surrounding Konya closed basin and its near vicinities. This work aims to significantly support AFAD's (Disaster and Emergency Management Authority) susceptibility ma...
ITU_GRACE16 is a static global gravity field model up to degree order 180 computed from GRACE SST data of 50 months collected between April 2009 to October 2013 by collaboration of various national institutions (YTU, KOU, NEU, SU) lead by ITU and OSU as the international collaborator with the support of research grant no 113Y155 from the Scientific...
ITU_GGC16 is a static global gravity field model up to degree order 280 computed from the combination of ITU_GRACE16 (up to d/o 180) and GO_CONS_GCF_2_TIM_R5 (up to d/o 280) by collaboration of various national institutions (YTU, KOU, NEU, SU) lead by ITU and OSU as the international collaborator with the support of research grant no 113Y155 from t...
The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve...
The precise orbit determination (POD) of satellites in Low Earth Orbits (LEO) has become a key technology for space missions. Especially, the contribution of LEO satellites to the recently developed gravity field models is significant. The orbits of these satellites can be tracked owing to the fact that satellite missions for gravity field determin...
InSAR (Interferometric synthetic aperture radar) techniques and applications are very useful for monitoring and mapping different types of deformations such as landslides, subsidence and volcanic activities on the Earth surface. In this research, we investigated Babadağ landslide (Denizli in western Turkey) by using the InSAR techniques and compare...
ZET Yerkabuğunun aktif deformasyon alanları, , birçok doğal afete neden olmuş ve olmaya devam etmektedir. Bunlardan başlıcaları, can ve mal kayıplarıyla insanoğlunun yaşamında derin izler bırakan depremler ve heyelanlardır. Bu afet türleri ile ilgili yapılan jeolojik ve çok disiplinli araştırmalar 20. Yüzyılın başından itibaren doğal afet zararları...
Nowadays, the geodetic community has aimed to determine 1-cm accuracy gravimetric geoid model, which satisfies the demands of most engineering applications. However, the gravimetric geoid determination is a difficult mission which needs an exclusive attention to obtain reliable results for this purpose. Today, Least-Squares Modification of Stokes (...
Nowadays, the geodetic community has aimed to determine 1-cm accuracy gravimetric geoid model, which satisfies the demands of most engineering applications. However, the gravimetric geoid determination is a difficult mission which needs an exclusive attention to obtain reliable results for this purpose. Today, Least-Squares Modification of Stokes (...
Konya Closed Basin that includes two depression blocks, Konya and Tuz Gölü, is the biggest endorheic basin in Turkey. A lowering in the ground levels of the depositional areas has been shown with respect to the surrounding mountains. In the past, this process was controlled by geological and hydrogeological phenomena; nowadays, it has gained a new...
The decrease of groundwater caused by the rapid increase in population, global warming, over-use of water resources, and other influences is one of the most important problems of the world. The problems coming from the decrease of groundwater are not limited to loss of water resources. Depending on the decreasing water volume, a deformation and com...
Recently, many organizations have begun providingonline GNSS (Global Navigation Satellite System)data processing services. Currently, only one of these organizationsi.e., OPUS (On-line Positioning Users Service)provides a rapid static data processing option. In case ofstatic online data processing, the users are required to submitat least two hours...
In this study, the usage and accuracy performance of internet based GNSS processing services are evaluated. The main advantages of them are that the services are free and they require minimum user experience when compared with commercial and scientific software packages. After processing observation data on the internet based services, the
performa...
ABSTRACT: In Çumra agriculture basin, the changes in spatial locations of the soil surface depending on groundwater level changes have been observed. In order to the monitoring x, y and z coordinates in topography of the basin, 25 GPS measurement stations units were built. In addition, the boreholes were drilled at 11 different points, which were v...
Üç boyutlu jeodezik uygulamalarda, jeoit ile elipsoit arasındaki aykırılığın konuma bağlı olarak bilinmesi, elipsoidal yüksekliklerden ortometrik yüksekliklere geçişi sağlamaktadır. Jeoit global bir problem olmasına karşın, daha sık verinin bulunduğu alanlarda problem bölgesel ölçeğe indirgenebilir. Bu çalışmada, astrojeodezik nivelman tekniği kull...
In mountainous regions with scarce gravity data, gravimetric geoid determination is a difficult task that needs special attention to obtain reliable results satisfying the demands, e.g., of engineering applications. The present study investigates a procedure for combining a suitable global geopotential model and available terrestrial data in order...
Accuracies of relative positioning techniques namely rapid static, pseudo-kinematic, kinematic, and real-time kinematic are investigated to determine their performances against static survey technique that yields the most precise results. Measurements are taken at seven National Geodetic Survey points along Road 714 in Florida using three sets of t...
Temporal and spatial variations occur in the Earth's gravity field continuously. The investigation of these variations provides information about the natural mass transportation and redistribution of these masses (surface and interior) in the Earth. Seasonal groundwater storage changes, water circulation between the oceans and continents, melting g...
Interferometric SAR (InSAR) technique produces a high resolution topographic map and also gives information about changes on the Earth's surface during the repeat pass cycle of a satellite from the correlation properties of the radar echo. This technique is often limited by temporal and geometrical decorrelation, therefore phase noise occurs on res...
The determination of the geoid, which is a real shape of the Earth, with an accuracy of 1 cm is one of the most important aim of the today’s geodetic community. The gravimetric geoid modeling is the most preferred technique in order to reach to this target. Nevertheless, the gravity values measured on the physical surface of the Earth can not be di...
The dedicated satellite gravity missions CHAllenging Minisatellite
Payload (CHAMP), Gravity Recovery and Climate Experiment (GRACE), and
Gravity field and steady-state Ocean Circulation Explorer (GOCE) and
their recent and expected Global Geopotential Models (GGMs) present new
opportunities for the determination of gravity-related heights. Global
P...
ÖZET Global jeopotansiyel modeller, yeryuvarının dış çekim alanını ve buna bağlı büyüklükleri sayısal olarak değerlendirmek için kullanılır. Küresel harmoniklere dayalı bu modellerin açınım dereceleri arttıkça, serilerde yer alan Legendre fonksiyonlarını hesaplamada temel araçlar olan yineleme bağıntıları kullanılamaz duruma gelir. Ortaya çıkan sor...
Son yıllarda interferometrik yapay açıklıklı radar tekniği, yeryüzünde meydana gelen deformasyonların incelenmesinde yeni bir araç olarak kullanılmaktadır. InSAR tekniği radar görüntülerini kullanarak yüksek çözünürlüklü topografya bilgisi (sayısal arazi modeli) üretmesinin yanı sıra yüzey deformasyonlarının belirlenmesinde de jeodeziye yeni bir ba...
Spectral evaluation of global geopotential models (GGMs) is necessary to recognize the behaviour of gravity signal and its error recorded in spherical harmonic coefficients and associated standard deviations. Results put forward in this wise explain the whole contribution of gravity data in different kinds that represent various sections of the gra...
One of the potential dangers that might arise as a result of bringing excessive amounts of groundwater to the surface of the Earth is land subsidence. Such surface deformations – these velocities may vary from a few millimetres to a few metres per year – do the greatest damage to infrastructure facilities and buildings in residential units. Agricul...
In February 2000, the Space Shuttle Endeavour of the “Shuttle Radar Topography Mission” (SRTM) launched by NASA collected elevation data by scanning the earth landmasses between ∼60º north and south parallels. After this 11 days mission, the collected data were processed, and a Digital Elevation Model (DEM) at 1-arc second – and also 3-arc-second –...
Depending on scale, topographic maps depicting the shape of the land surfaces of the Earth are produced from different data sources. National topographic maps at a scale of 1:25 000 (25K maps) produced by General Command of Mapping are used as the base map set in Turkey. This map set, which consists of approximately 5500 sheets, covers the whole co...
Topographic maps that show the shape of land surfaces of the Earth are derived from different data sources depending on the map scale. National topographic maps with the scale of 1:25 000 (25K maps) are used as the base topographic map set published by General Command of Mapping in Turkey. This map set, which consists of approximately 5 500 sheets,...
In February 2000, the "Shuttle Radar Topography Mission" satellite launched by NASA captured elevation data by scanning the Earth landmasses between the ~60º North and South parallels. After the mission of 11 days, the collected data were processed, and a Digital Elevation Model (DEM) with 1×1 arc second resolution was created. Thereafter, the firs...
A long-range geoid testing procedure is presented using a geometrical geoid profile, which extends in an approximate north-south direction between the Mediterranean and the Black Sea. Along the first-order leveling line of the Turkish National Vertical Control Network (TNVCN), 47 leveling benchmarks at 20-25 kin intervals were selected as global po...
On February 2000, The Shuttle Radar Topography Mission (SRTM) Satellite collected global topographic data using a multifrequency radar system. The precision of the height information for a global model data is so high that is never reached before. Many research institutions and national mapping agencies have been testing the quality and reliability...
The geoid profile, which extends nearly in north-south direction between Antalya and Samsun tide gauges, is determined by GPS/levelling along the first order levelling line of Turkish National Vertical Control Network (TNVCN). 47 levelling benchmarks at 20-25 km intervals were selected as GPS/levelling points with known Helmert orthometric heights....
CHAMP, GRACE and GOCE satellites are low Earth orbiters which will be used for the determination of the Earth's gravity field. The mission of the satellites is to provide the knowledge for the gravity field that leads to observe the Earth system for geodetic and geodynamic purposes with a sufficient accuracy. The characteristics specific to the sat...
Özet: Yeryuvarõnõn kitle dağõlõmõ tam olarak bilinmediğinden V dõş çekim potansiyeli, ∆ V = 0 Laplace diferansiyel denkleminin çözümünü veren harmonik fonksiyonlar ile gösterilir. Bu gösterimde matematiksel bir kolaylõk sağladõğõ için genellikle küresel harmonikler kullanõlmaktadõr. Ancak kutuplardan basõk bir dönel elipsoit yeryuvarõnõn gerçek şek...
SMALL/SCALE MAP DESIGN USING GIS: THE MAP OF KONYA PROVINCE The rapid developments in information technologies, and also in geographic information systems (GIS) have affected cartography. Today, most maps have been designed in a GIS environment, either following the cartographic rules or not. Although the GIS software packages have been well develo...
