Sercan Bülbül

COMPARISON OF REGIONAL AND GLOBAL TEC VALUES: TURKEY MODEL

The ionosphere is a layer of atmosphere 60 km to 1,100 km above the earth and is composed of solar rays and ionized gases. The ionosphere is an important layer affecting Global Navigation Satellite System (GNSS) measures. The quality of GNSS measures is directly related to the changes in the ionosphere. For this reason, monitoring changes in the ionosphere is quite important. One of the important parameters expressing the characteristic of the ionosphere is the Total Electron Content (TEC), which is a function of electron density exhibiting transformation with solar radiation. In this study, 68 stations including 56 TUSAGA-Active (CORS-TR) stations and also IGS stations were taken for evaluation. Bernese v5.2 GNSS software developed by Bern University of Switzerland was employed at the evaluation stage. From 2009 until 2015, TEC values were calculated at two hourly intervals, one day for each month. In the study, where a Single Layer Model was used, TEC values obtained from GNSS measurements have been compared with the TEC (IRI-2012 TEC) values obtained from the global ionosphere map (GIM-TEC) and the international ionosphere reference model programme published by the Centre for Orbit Determination in Europe (CODE), the European Space Agency (ESA), and the Jet Propulsion Laboratory (JPL).

Statistical analysis of accuracy and precision of GNSS receivers used in network RTK

It is important to make accurate and precise measurements in surveying applications. The concepts of accuracy and precision are not synonymous, even though they are commonly used in place of each other. Nowadays, real-time kinematic (RTK) method is widely used at surveying. As the RTK method can be done depending on a reference station, in countries which establish Continuously Operating Reference Stations (CORS) Network, method known as Network-RTK (N-RTK) can be done depending on the CORS Network. Continuously Operating Reference Stations-Turkey Network (CORS-TR), which consists of 146 reference stations that allow positioning both real time and post-process, was established in 2009. In this study, accuracy and precision of Global Navigation Satellite Systems (GNSS) receivers are tried to determine depending on different correction techniques. For this purpose, 12-h GNSS observations were performed at SLCK-Turkish National Fundamental GPS Network (SLCK-TNFGN) point. The observations were adjusted based on CORS-TR. N-RTK measurements were performed with different GNSS receivers, and accuracies of the receivers were investigated. In order to determine precisions of the receivers, means of RTK measurements were calculated and precisions of the receivers were determined. As a result of investigation, it is seen that accuracy and precision of receivers at 2D positioning and height vary depending on correction technique.

Surveying and Mapping Using Mobile Phone in Archeological Settlements

Depending on the development of technology, the boundary concept between different disciplines became unclear today and it became necessary to work jointly depending on data sharing. Also Producing the maps is effected the development of the technology and positioning of desired area is become very fast. Today, instead of hand GPS, users can be obtained coordinate desired via programs which are compatible with mobile phone. CORS (Continuously Operation Reference System) GNSS (Global Navigation Satellite System) receivers which measure points coordinates (x, y, h) at all weather conditions, day and night will become compatible Mobil PC devices (Mobil Phone) via compatible software. By means of this study, including the surveys of Ancient History and Archaeology sciences, different samples belonging to different periods have been evaluated. In this study, coordinates obtained with CORS-TR (Continuously Operation Reference SystemTuRkey) and Asus Zenfone 6 in which Kocaman Pro Software was used at selected areas compare with each and the usage of Asus Zenfone 6 was investigated in term of easiness and accuracy in Archaeological Settlements. This study was carried out at the Hatıp Castle, Malas II and Campus ruins in Konya. Only horizontal accuracy (x, y) was investigated. The horizontal accuracy is higher in Malas II and Campus ruins than Hatıp Castle. This is due to the distance of the GSM networks to the application area. Key-words: Map, Coordinates, Measurement, Accuracy, Mobile Phone, Archaeological Settlement.

Determining regional ionospheric model and comparing with global models

IZVLEČEK KLJUČNE BESEDE

Repeatable of Network RTK Measurement

Anahtar kelimeler GNSS; Klasik RTK; Ag RTK; Hizli statik yontem Ozet Gunumuzde nokta konumlarinin GPS/GNSS(Global Positioning System/Global Navigation Satellite Systems) ile gercek zamanli belirlenmesi genel olarak Klasik RTK(Real Time Kinematic) ya da Ag RTK(CORS: Continuously Operating Reference Stations) ile yapilmaktadir. CORS agini kuran ulkelerde ise Ag RTK yontemi tercih edilmektedir. Bu calismada Ag RTK olculerinin tekrarlanabilirligi test edilmistir. Olcmeler Selcuk Universitesi Kampus alaninda bulunan TUTGA(Turkiye Ulusal Temel GPS Agi) SLCK noktasinda farkli duzeltme teknikleri kullanilarak gerceklestirilmistir. Secilen duzeltme tekniklerinde olcmeler ucer gun sure ile 10-14 saatleri arasinda yapilmis, elde edilen koordinatlarin gunluk degisimi ve bilinen koordinatlara yaklasimi arastirilmistir. Yapilan degerlendirmelerde; gun icindeki koordinat farklarinin secilen duzeltme teknigine gore farklilik gosterdigi, yukseklik yonundeki farklarin x ve y yonundeki farklarin yaklasik 2 kati oldugu, gercek degere en iyi yaklasimi VRS tekniginin gosterdigi, butun duzeltme tekniklerinde elde edilen koordinatlarin bilinen koordinatlarla istatistiki anlamda uyusumlu oldugu sonucuna varilmistir.