Profile URL: https://hdl.handle.net/20.500.13091/11931
Job Title:Doç. Dr.
Email Address:sbulbul@ktun.edu.tr
Main Affiliation:02.08. Department of Geomatic Engineering
Status: Current Staff
ORCID:
0000-0001-6066-611X
0000-0001-6066-611XScopus ID:
57196346482
57196346482YÖK Akademik: 2EE93033BC96ED7C
Google Scholar:
thiqfZoAAAAJ
thiqfZoAAAAJWeb of Science ID:
ABF-6270-2021
ABF-6270-2021Name Variants:
Bulbul, Sercan
32 results
Scholarly Output Search Results
Now showing 1 - 10 of 32
Article Farklı Uydu Sistemi Kombinasyonlarının Gerçek Zamanlı Hassas Nokta Konumlamaya Etkisi(2022) İnal, Cevat; Bilgen, Burhaneddin; Bülbül, Sercan; Başbük, MusaHassas Nokta Konumlama (PPP) yöntemi, gerçek zamanlı (RT-PPP) ve ölçü sonrası değerlendirme (PP-PPP) olmak üzere iki şekilde uygulanmaktadır. Bu çalışmada, jeomanyetik aktivitelerin GNSS gözlemleri üzerindeki bozucu etkisinin sonuçlara yansımaması amacıyla Kp, Dst ve F10.7 indisleri incelenmiş ve jeomanyetik aktivitelerin olmadığı 30 ardışık gün belirlenmiştir. Yüksek, orta ve alçak enlem bölgelerinde bulunan Uluslararası GNSS Servisi-Multi GNSS Experiment istasyonlarından KIR8, PADO, NKLG’nin bu ardışık günlere ait Alıcıdan Bağımsız Veri Değişim Formatı (RINEX) verileri RTKLIB v2.4.3 yazılımı ile çözümlenmiştir. Daha sonra, elde edilen kartezyen koordinatlar gerçek değerlerle karşılaştırılmıştır. Ayrıca, her bir istasyona ait koordinat eksenleri yönündeki karesel ortalama hatalar ve konum ortalama hataları hesaplanarak farklı uydu sistemi kombinasyonlarının RT-PPP’ye etkisi incelenmiş, genellikle desimetre mertebesinde ortalama hatalar elde edilmiştir. Elde edilen ortalama hatalar değerlendirildiğinde; RT-PPP yönteminin jeodezik uygulamalardan beklenen doğruluğu henüz sağlayamadığı görülmekte, fakat gelecekte hem alıcı hem de antenlerin RT-PPP’yi destekler hâle gelmesi ve yayınlanan gerçek zamanlı düzeltmelerin iyileştirilmesiyle jeodezik uygulamalar için gerekli doğruluğu sağlayabileceği beklenmektedir.Article Web Tabanlı GNSS Yazılımlarının Konum Doğruluğu Üzerine Karşılaştırmalı İncelemesi(2025) Bulbul, Sercan; Inal, Cevat; Bilgen, Burhaneddin; Gul, NevriyeGNSS alıcıları ile toplanan verilerin bilimsel ve ticari yazılımlar ile değerlendirilmesi için iyi bir program bilgisi ve yazılımların belirli bir ücret karşılığında satın alınması gerekmektedir. Bu durumu aşmak amacıyla bazı kurumlar ve firmalar, ücretsiz ve web tabanlı çevrimiçi GNSS değerlendirme yazılımları geliştirmiştir. Bu çalışmada, söz konusu yazılımların (CSRS-PPP, MagicGNSS, APPS, Trimble-RTX, IBGE-PPP, IGN-PPP, raPPPid, PPPH, AUSPOS, OPUS) performansları, uzay iklim koşulları göz önüne alınarak analiz edilmiştir. Beş farklı IGS istasyonuna (NOT1, SULP, ANK2, BOR1, MIKL) ait veriler mutlak (PPP) ve bağıl konumlandırma yöntemleriyle değerlendirilmiş ve uzay iklim koşullarının GNSS ölçüleri üzerindeki olumsuz etkisini ortadan kaldırmak amacıyla uzay iklim koşullarının etkisinin minimum olduğu bir gün seçilmiştir. 6, 12 ve 24 saatlik veri bölümleriyle yapılan analizde, elde edilen koordinatlar web tabanlı bağıl konum belirleme ve SNX dosyasından elde edilen koordinatlar ile karşılaştırılmıştır. Sonuç olarak, yazılımlar arasında doğruluk farkları gözlenmiş, gözlem süresinin doğruluk üzerinde önemli etkisi olduğu belirlenmiş ve özellikle PPPH yazılımının daha yüksek konum farkları ürettiği tespit edilmiştir.Article Investigation of the Effect of Annual Average Temperature and Precipitation Changes on Cors-Tr Stations: the Case of Kstm Station(Konya Teknik Univ, 2024) Acar, Alparslan; Bülbül, Sercan; Başçiftçi, Fuat; Yıldırım, ÖmerIn this study, the effects of meteorological changes on the point positioning of CORS-TR stations were investigated. For this purpose, KURU, SINP, BOYT, CORU, CANK, CMLD, KRBK, KSTM stations were selected. The KSTM station was taken as unknown and adjusted based on other stations. Seasonal normal values of KSTM station in Kastamonu province covering the years 2016-2020 were examined in terms of temperature and precipitation amount. These values were determined according to the minimum, maximum and average value criteria by using T & uuml;rkiye State Meteorological Service data. For the calculations, IGS-standardized RINEX data of the stations for 5 years and 12 months between 2016 and 2020 and for 10 days on the 11th th and 20th th days of each month were used. All calculations were processed with Leica Geo Office v8.x. The calculated coordinates were compared with the current coordinates of CORS-TR at the same epoch and examined according to annual temperature and precipitation. In the analyzes, it was tested by statistical method whether all measurements were compatible. When it was examined whether the temperature changes were statistically significant, it was observed that the test values were calculated according to the temperature changes were below the test distribution limit at 95% confidence interval. When it was examined whether the precipitation changes were statistically significant, it was observed that the test values were calculated according to the precipitation changes were below the test distribution limit at 95% confidence interval.Other Examination of the Relationships between TEC Changes and Space Weather Conditions Before and After the February 6, 2023 Kahramanmaraş Earthquake (Mw= 7.8 and Mw=7.5)(2024) Bülbül, SercanAbstract Earthquakes are major natural disasters that cause loss of life and property. Predicting earthquakes in advance is highly important. In recent years, GNSS measurements have been used to predict earthquakes, particularly by analysing total electron content (TEC) values obtained from these measurements. However, it is crucial to accurately analyse the TEC changes influenced by space weather conditions and distinguish them from those caused by earthquakes. This study investigated the impact of the Pazarcık-Kahramanmaraş (Mw: 7.8) and Ekinözü-Kahramanmaraş (Mw: 7.5) earthquakes that occurred on February 6, 2023, on TEC changes. To achieve this goal, space weather conditions, such as the Kp, Dst (nT), F10.7 (sfu), P (\(N⁄c{m}^{3}\)), Bx (nT), By (nT), and Bz (nT) indices, were examined for one month before and after the earthquake occurred. Potentially active days were identified. After establishing space weather conditions, their impact on TEC changes was investigated. The results indicated that there was no significant influence of space weather conditions on TEC changes during the selected time frame, suggesting that these changes may be attributed to the earthquake. Additionally, CODE-TEC and ESA-TEC values for the selected time frame were obtained using the coordinates of 15 CORS-Tr stations in the earthquake region. The upper and lower boundary values of the TEC were determined, and days with anomalies were identified. As a result, it was found that there were days with a positive anomaly approximately 15–18 days before the occurrence of possible earthquakes, which could serve as a preparation period. Furthermore, postearthquake anomalies were suggested to potentially be caused by aftershocks.Article Citation - WoS: 4Citation - Scopus: 5A New Precise Point Positioning With Ambiguity Resolution (ppp-Ar) Approach for Ground Control Point Positioning for Photogrammetric Generation With Unmanned Aerial Vehicles(MDPI, 2024) Makineci, Hasan Bilgehan; Bilgen, Burhaneddin; Bulbul, SercanUnmanned aerial vehicles (UAVs) are now widely preferred systems that are capable of rapid mapping and generating topographic models with relatively high positional accuracy. Since the integrated GNSS receivers of UAVs do not allow for sufficiently accurate outcomes either horizontally or vertically, a conventional method is to use ground control points (GCPs) to perform bundle block adjustment (BBA) of the outcomes. Since the number of GCPs to be installed limits the process in UAV operations, there is an important research question whether the precise point positioning (PPP) method can be an alternative when the real-time kinematic (RTK), network RTK, and post-process kinematic (PPK) techniques cannot be used to measure GCPs. This study introduces a novel approach using precise point positioning with ambiguity resolution (PPP-AR) for ground control point (GCP) positioning in UAV photogrammetry. For this purpose, the results are evaluated by comparing the horizontal and vertical coordinates obtained from the 24 h GNSS sessions of six calibration pillars in the field and the horizontal length differences obtained by electronic distance measurement (EDM). Bartlett's test is applied to statistically determine the accuracy of the results. The results indicate that the coordinates obtained from a two-hour PPP-AR session show no significant difference from those acquired in a 30 min session, demonstrating PPP-AR to be a viable alternative for GCP positioning. Therefore, the PPP technique can be used for the BBA of GCPs to be established for UAVs in large-scale map generation. However, the number of GCPs to be selected should be four or more, which should be homogeneously distributed over the study area.Article Towards Geodetic-Level Accuracy in Low-Cost GNSS: Tectonic Velocity Determination Capabilities of the U-Blox Zed-F9p Over a Year Multi-GNSS PPP-AR Time Series(Elsevier Sci Ltd, 2026) Duman, Huseyin; Ogutcu, Sermet; Alcay, Salih; Ozdemir, Behlul Numan; Atiz, Omer Faruk; Bulbul, SercanThe growing availability of low-cost dual-frequency GNSS receivers is enhancing their suitability for various kinds of geodetic applications. Geodetic monitoring of the continuous crustal deformation using GNSS time series analysis is one of the commonly used geodetic applications. To maintain the most accurate estimated parameters such as secular velocity, seasonal signal parameters and offsets, geodetic-grade GNSS receivers are commonly used in the GNSS time series analysis. However, due to the increasing availability of low-cost dual-frequency GNSS receivers and advancements in software and hardware, these receivers have now reached a level that supports the GNSS time series analysis. In this study, over a year of multi-GNSS PPP-AR time series of the u-blox ZED-F9P low-cost GNSS receiver are investigated by evaluating the accuracy of the estimated parameters, comparing them with data from a geodetic-grade GNSS receiver monumented on a building roof. The results show that the minimum detrended standard deviation obtained from White Noise (WN) estimation is achieved using GPS + GLONASS + Galileo PPP for both receivers. The computed annual velocity and amplitude differences obtained from the GNSS time series between the u-blox ZED-F9P and the geodetic-grade GNSS receivers using GPS + GLONASS + Galileo PPP-AR are found as 0.6 mm / 0.4 mm / 0.8 mm and 1.5 mm / 0.4 mm / 0.2 mm for north, east, and up components, respectively. (c) 2025 COSPAR. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Article Citation - WoS: 2Citation - Scopus: 2Investigation of Tec Anomalies Possibly Caused by the 6 February 2023 Kahramanmaraş(turkey) Earthquakes With Space Weather Conditions(Ist Nazionale Di Oceanografia E Di Geofisica, 2024) Bulbul, S.This study investigates the Total Electron Content (TEC) variations associated with major earthquakes in Kahramanmara & scedil;(Turkey) on 6 February 2023, utilising Global Navigation Satellite System (GNSS) measurements and TEC values published by the Jet Propulsion Laboratory. Covering a 37-day period, including 18 pre/post-earthquake days, TEC values, originally from 15 CORS-TR stations in the earthquake region, were analysed in the gridded version. The study assesses pre/post-earthquake anomalies with the purpose of differentiating TEC changes caused by seismic events from those influenced by space weather conditions (SWCs). The examination of SWCs (disturbance storm time, geomagnetic storm index, GSM interplanetary magnetic field, solar wind speed, pressure, electric field, and proton density) reveals a general pre-earthquake quietness. Positive and negative TEC anomalies observed at the station locations during the study period indicate seismic events as potential precursors. Post-earthquake anomalies on 15 and 16 February 2023 are likely linked to SWCs and aftershocks. The study concludes that earthquake-induced TEC variations manifest approximately 16 days before the event, with positive anomalies, transitioning to both positive and negative anomalies approximately eight days before the earthquake. This suggests an eight-day period as a potential earthquake precursor, emphasising the potential for a future development of an early earthquake warning system through the integrated analysis of TEC variations and SWCs.Article Citation - Scopus: 2Investigation of Possible Causes of Ionospheric Anomalies Pre/Post-earthquakes Based on Space Weather Conditions (swc)(INDIAN ASSOC CULTIVATION SCIENCE, 2023) Bülbül, SercanEarthquakes in the world from past to present have caused many loss of life and property. Earthquake forecasting studies are very important in order to prevent destructive effects of these loss of life and property. Total electron content (TEC) is a component that can be easily used to predict natural disasters such as earthquakes. TEC values can be calculated according to the desired location with the help of dual-frequency GNSS receivers and GPS satellites surrounding the whole world. However, it is impossible to predict a possible earthquake with only TEC values. For this purpose, TEC values should be examined together with indices such as space weather conditions indices, and then a possible forecast scenario should be determined. In this study, GPS-TEC anomalies were investigated with possible causes of ionospheric anomalies based on space weather conditions (SWC) indices such as solar activity (EUV and F10.7), geomagnetic activity (Dst), geomagnetic storm (Kp), magnetic field changes (Bz), proton density (Np) changes in the Sivrice-Elazig earthquake (Mw 6.8) that occurred on January 24, 2020, and the Seferihisar (Izmir) earthquakes (Mw 6.6) that occurred on October 30, 2020, in the Aegean Sea off the coast of Seferihisar-Izmir.Article Strain Analysis of the Kahramanmaraş Earthquakes (6 February 2023) Using Cors-Tr Data(Konya Teknik Univ, 2026) Inal, Cevat; Bulbul, Sercan; Ozer, Eda; Gundogan, TunahanTürkiye is a seismically active region, which frequently leads to the occurrence of earthquakes across the country. The high seismic activity and frequent earthquakes in Turkey have attracted the attention of many researchers. Using Global Navigation Satellite Systems (GNSS), one of the fundamental geodetic measurement techniques, it is possible to compute earthquake-induced displacements and perform strain analyses. This study aims to determine the strains caused by the earthquakes that occurred on February 6, 2023, in Kahramanmaraş, using data from the Continuously Operating Reference Stations-Türkiye (CORS-TR). For this purpose, a total of 31 days of 24-hour RINEX data, including pre-earthquake, post-earthquake, and earthquake-day, from 21 CORS-TR stations were analyzed. These datasets were processed using GAMIT/GLOBK, AUSPOS, and Trimble-RTX software, and two-dimensional strain analyses were conducted based on the derived coordinates. The study area was divided into 28 triangular elements, with the CORS-TR stations serving as vertices, and strain analyses were performed for each triangle. The results reveal that the largest strains occurred in the EKZ1-MAR1-ANTE and EKZ1-ANTE-MLY1 triangles, due to the proximity of EKZ1, MAR1, ANTE, and MLY1 stations to the epicentres. Moreover, considering the coordinate displacements, the largest shifts were observed at EKZ1, MLY1, MAR1, ANTE, and TUF1 stations, respectively. Based on this observation, each station was subsequently selected as a reference point, and strain parameters were computed relative to directions originating from these reference points. The parameters obtained from different software packages were consistent with each other, similar to the triangular division method.Article Galileo Uydu Sisteminin Bağıl Konum Belirlemeye Katkısının Araştırılması(2021-12-31) Bülbül, SercanGünümüzde nokta koordinatları GNSS tekniğiyle de belirlenmektedir. Yüksek doğruluk gerektiren uygulamalarda GNSS tekniklerinden bağıl konum belirleme teknikleri yaygın olarak tercih edilmektedir. Bağıl konum belirleme yöntemlerinden statik ölçü ve bu ölçülerin değerlendirilmesinde ise farklı uydu konfigürasyonları kullanılmaktadır. İlk olarak sadece GPS (G) uyduları kullanılırken, zamanla farklı kurum ve kuruluşlar tarafından geliştirilen önce GLONASS (R) daha sonra GALİLEO (E) uydu sistemleri ile nokta koordinatları belirlenmeye başlanmıştır. Gerçekleştirilen bu çalışmada, GALİLEO uydu konfigürasyonunun nokta koordinat ve konum doğruluklarına etkisi araştırılmıştır. Bu kapsamda 6 adet IGS-MGEX istasyonundan oluşan bir jeodezik ağ oluşturulmuştur. Seçilen ağa ilişkin 31 günlük ( 01-31.08.2017) 24 saat RINEX verileri Bernese v5.2 Bilimsel GNSS değerlendirme yazılımında ikili farklar yöntemi ile G, G+R ve G+R+E farklı uydu konfigürasyonunda değerlendirilmiştir. Karşılaştırmada ITRF2014 (2010.00 referans epoğu) koordinatları hız değerleri ile ölçü epoğuna kaydırılarak elde edilen koordinatlar gerçek değerler olarak alınmıştır. Daha sonra koordinat eksenleri yönündeki karesel ortalama hatalar (koh) ve konum doğrulukları hesaplanarak istatistiksel olarak birbirleri ile karşılaştırılmıştır. Karşılaştırma sonucunda ise G, G+R ve G+R+E uydu konfigürasyonları ile elde edilen konum doğrulukların %95 güven aralığında birbirleri ile uyuşumlu olduğu belirlenmiştir.
Research Topics
Domains
Physical Sciences
Fields
EngineeringEarth and Planetary SciencesPhysics and Astronomy
Subfields
Aerospace EngineeringOceanographyGeophysicsAstronomy and Astrophysics
Specific Research Areas
GNSS positioning and interference
Inertial Sensor and Navigation
Geophysics and Gravity Measurements
Earthquake Detection and Analysis
Ionosphere and magnetosphere dynamics
Sustainable Development Goals
11SUSTAINABLE CITIES AND COMMUNITIES
5
Research Products
Documents
18
Citations
114
h-index
6
Documents
21
Citations
113
Publication Collaboration
| Affiliation Name | Count |
|---|---|
| Konya Technical University | 24 |
| Selçuk University | 7 |
| Tokat Gaziosmanpaşa Üniversitesi | 5 |
| Ankara Hacı Bayram Veli University | 5 |
| Karamanoğlu Mehmetbey University | 5 |
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Data obtained from OpenAlex
| Journal | Count |
|---|---|
| Niğde Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi | 3 |
| Konya mühendislik bilimleri dergisi (Online) | 3 |
| Advances in Space Research | 2 |
| Afyon Kocatepe Üniversitesi Fen ve Mühendislik Bilimleri Dergisi | 2 |
| Bulletin of Geophysics and Oceanography | 2 |
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Scholarly Output
32
Articles
30
Views / Downloads
68/57
Supervised MSc Theses
1
Supervised PhD Theses
0
WoS Citation Count
74
Scopus Citation Count
88
Patents
0
Projects
0
WoS Citations per Publication
2.31
Scopus Citations per Publication
2.75
Open Access Source
19
Supervised Theses
1
Scopus Quartile Distribution
Competency Cloud
