Taylan Ocalan

• Doctor of Philosophy
• Yıldız Technical University

Recently, photogrammetric products produced using Unmanned Aerial Vehicles (UAVs) are frequently preferred for disaster management, geological, and meteorological studies, urban studies and military purposes. Obtaining products with UAV photogrammetry provides a significant advantage over ground-based methods in terms of speed and cost. At the same...

Connecting Asia and Europe, Türkiye is vital for maritime transit, which requires continuous and precise sea level monitoring. Traditional tide gauges (TGs), while valuable, often have data gaps. GNSS-IR provides an alternative, though aligning it with TG measurements is challenging. This study introduces a method to estimate Vertical Local Tie (VL...

Taşınabilir ve giyilebilir akıllı mobil cihazların (telefon, tablet, kol saati, gözlük vb.) önemi dijitalleşen mekânsal bilgi endüstrisinde her geçen gün artmaktadır. Akıllı telefonlar gerek kullanım oranı gerekse ekonomik pazar payıyla bu endüstride ön plana çıkmaktadır. Profesyonel donanımlara kıyasla görece düşük maliyetli olan ve birçok sensör...

Determining and monitoring ground deformations is critical for hazard management studies, especially in megacities, and these studies might help prevent future disaster conditions and save many lives. In recent years, the Golden Horn, located in the southeast of the European part of Istanbul within a UNESCO-protected region, has experienced signifi...

Deniz seviyesi değişimi hem iklim bilimsel çalışmalarda hem de yerkürenin jeodinamik süreçlerinin izlenmesinde ve açıklanmasında ihtiyaç duyulan, sürekli olarak gözlemlenmesi gereken önemli bir değişkendir. Deniz seviyesi gözlemleri günümüzde uydu ve yer tabanlı ölçme sistem ve teknolojileri kullanılarak küresel, bölgesel ve yerel ölçeklerde gerçek...

The 6 February 2023 Mw 7.8 Pazarcık and subsequent Mw 7.5 Elbistan earthquakes generated strong ground shaking that resulted in catastrophic human and economic loss across south-central Türkiye and northwest Syria. The rapid characterization of the earthquakes, including their location, size, fault geometries, and slip kinematics, is critical to es...

According to the recent developments on image acquisition via relatively low-cost devices such as smartphones or tablets, researches on Structure-from-Motion (SfM) photogrammetry-based 3 dimensional (3D) model reconstruction become more popular and wide frequent practice especially for study areas in geology/geomorphology, historical heritage, fore...

An earthquake doublet (Mw 7.8 and Mw 7.6) occurred on the East Anatolian Fault Zone (EAFZ) on February 6th, 2023. The events produced significant ground motions and caused major impacts to life and infrastructure throughout SE Türkiye and NW Syria. Here we show the results of earthquake relocations of the first 11 days of aftershocks and rupture mo...

An earthquake doublet (Mw 7.8 and Mw 7.6) occurred on the East Anatolian Fault Zone (EAFZ) on February 6th, 2023. The events produced significant ground motions and caused major impacts to life and infrastructure throughout SE Türkiye and NW Syria. Here we show the results of earthquake relocations of the first 11 days of aftershocks and rupture mo...

Recently, an enormous number of concepts have been introduced as new insights into seismogeodetic tools and algorithms. Integration of Global Navigation Satellite Systems (GNSS) with accelerometers is a well-known and widely used approach for estimating co-seismic displacements. In this study, we present a two-stage Kalman Filtering (TSKF) approach...

Traditionally, photogrammetric product accuracy at cm level is obtained with Ground Control Points (GCP) in UAV photogrammetry. In recent years, UAVs equipped with Post-Processing Kinematic & Real-Time Kinematic (PPK/RTK) have become widespread. Accuracy in cm-level can be obtained with relative/differential positioning with these equipment. On the...

Global Navigation Satellite Systems (GNSS) can effectively provide semi-static and dynamic displacements by kinematic data processing of high rate observables without any numerical integration process unlike classical seismological sensors such as accelerometers. However, the noise amplitude of the high rate GNSS (HR-GNSS) derived displacements is...

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...

In the next generation, the use of dual-frequency Embedded GNSS Chipset in the smart devices, which will be widely used in engineering applications, has been used for the first time in Xiaomi Mi8. Considering this development dynamics, a kinematic test was carried out in the marine environment monitoring with a geodetic GNSS receiver and an android...

Here, we present the source mechanism and rupture process for the destructive 24 January 2020 Mw 6.7 Doğanyol–Sivrice earthquake at the East Anatolian Fault Zone (EAFZ, Turkey), obtained from seismological waveform analysis and space geodetic observations. Multi-data analyses and modelling in the present study provide fundamental data and strong co...

Here, we present the results of a kinematic slip model of the 2020 Mw 6.7 Doğanyol-Sivrice, Turkey Earthquake, the most important event in the last 50 yr on the East Anatolian Fault Zone. Our slip model is constrained by two Sentinel-1 interferograms and by 5 three-component high-rate GNSS (Global Navigation Satellite System) recordings close to th...

Today, photogrammetric products such as high accurate ortho-images, point clouds and Digital Surface Model (DSM) can be generated by Unmanned Aerial Vehicle (UAV) photogrammetry using Ground Control Point (GCP). In addition to this, several researches have been conducted to generate high accurate ortho-images, point clouds and DEMs by UAVs that hav...

Here we present the results of a kinematic slip model of the 2020 Mw 6.7 Doğanyol-Sivrice, Turkey Earthquake, the most important event in the last 50 years on the East Anatolian Fault zone. Our slip model is constrained by two Sentinel-1 interferograms and by 5 three-component high-rate GNSS recordings close to the earthquake source. We find that m...

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...

Coordinate transformation from one datum to another is the basic problem in geodesy. Generally, the problem may be expressed by converting coordinates in a cartesian coordinate system with defined origin provided by intersection of two axes into another system using mathematical equations. To compute the transformation parameters, sufficient number...

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...

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...

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...

Determination of Snow Depth Using Reflected GPS Signals

The Unmanned Aerial Vehicle (UAV) has been successfully used in many different fields such as military, forest fire, archaeological sites, agricultural applications, traffic control, radiation monitoring, natural disasters and investigating of forest lands. Ortho-images and Digital Surface Model (DSM) produced by data obtained from UAV are higly va...

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...

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,...

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...

Kako je Globalni položajni sustav (GPS) rutinski proveden u mnogim tehnički projektima, također je učinkovito primijenjen u procjeni i zaštiti šumskih i prirodnih izvora. Ovisno o preferiranoj metodi snimanja GPS-om u primjeni na šumskim područjima, mogu se postići različite razine preciznog određivanja položaja. Tradicionalno, u mnogim slučajevima...

Global Navigation Satellite Systems (GNSS) consist of satellite technologies such as GPS, GLONASS, BeiDou and Galileo. These technologies have effectively been used in many application areas. GNSS Continuously Operating Reference Stations (CORS) have also been applied successfully in many areas of forested industry. Typical applications include fir...

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...

The transition curves in the modern highway and railway construction are route elements equally crucial as alignment and curve (circular). In order to prevent a sudden change of the centrifugal force, the transition curve must be applied due to the impact of the motion in a sharp curve. Over the years the application of the clothoid has become wide...

Global Navigation Satellite Systems (GNSS) consist of satellite technologies such as GPS, GLONASS, BeiDou and Galileo. These technologies have effectively been used in many application areas. GNSS Continuously Operating Reference Stations (CORS) have also been applied successfully in many areas of forested industry. Typical applications include fir...

Since Global Positioning System (GPS) has been routinely conducted in many engineering projects, it is also effectively applied to the assessment and preventing of forest and natural resources. Depending on the GPS survey method preferred in the applications performed around the forest environments, different level point positioning accuracy can be...

This study investigates the accuracy of an online Precise Point Positioning (PPP) service operated by the Geodetic Survey Division of Natural Resources Canada (NRCan), Canadian Spatial Reference System (CSRS)-PPP, by using single/dual-frequency Global Positioning System (GPS) data collected by dual-frequency geodetic-grade and Original Equipment Ma...

Turkey occupies a critical segment in the Alpine-Himalayan orogenic belt that is characterized by many active fault lines. Numerous earthquakes of varying magnitudes have occurred on these fault lines over the years. A significant portion of these earthquakes have been recorded along the Fethiye Burdur Fault Zone (FBFZ). Unfortunately, the latest e...

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...

Preserving forests and their value to us is indispensable to human life. When making forest preservation plans and managing forests efficiently, it is necessary to use three dimensional (3D) models of the forest regions. Apart from the traditional and photogrammetric methods used for producing these maps, the LIght Detection and Ranging (LIDAR) mea...

We know that position accuracies from relative and static Global Positioning System (GPS) measurements are degraded by a variety of physical, hardware and software effects. As a result, users often take special precautions to minimise these effects and, hopefully, improve their accuracies when planning and making measurements. In this study, the ef...

Today, global navigation satellite systems (GNSS), real time differential correction techniques, CORS networks, GNSS user equipments, wireless communications and networking (WCN) systems, cellular systems, mobile navigation and Internet GPS are the systems used for different purposes in scientific, commercial and daily life areas. The latest innova...

Today, global navigation satellite systems (GNSS), real time differential correction techniques, CORS networks, GNSS user equipments, wireless communications and networking (WCN) systems, cellular systems, mobile navigation and Internet GPS are the systems used for different purposes in scientific, commercial and daily life areas. The latest innova...

Nowadays, highway transportation planning has become a significant problem due to the increased transportation need. Considering the problem as a whole, it is existed intricate subject by the help of constrictions of the land use areas, planning the transportation networks due to the residential areas because of irregular urbanization, penetrated c...

SUMMARY Nowadays, highway transportation planning has become a significant problem due to the increased transportation need. Considering the problem as a whole, it is existed intricate subject by the help of constrictions of the land use areas, planning the transportation networks due to the residential areas because of irregular urbanization, pene...

The length based engineering problems such as highways, railways etc. acquires three- dimensional topographic data to expose the project details. In view of highway transportation planning projects, to expose the existing situation accurately and rapidly has become a significant problem due to the increased transportation need. Therefore, three-dim...

SUMMARY Practical engineering applications for determination of observation stations for topographic and cadastral surveys and staking application are required traversing. GPS one of the efficient and optimum surveying techniques has been using routinely for positioning of the traverse points among the satellite-based surveying. In our days, many s...