Usability of turkish national gnss permanent network-active points for detecting deformations

GPS (Global Positioning System), which came into our lives in 1980s and opened to civilian use in 2000s, has been used extensively in surveying applications. In the following years, the satellite systems of other countries such as Russian GLONASS, China Beideu, India IRNSS and European Union GALILEO also became operational and the system was named as GNSS (Global Navigation Satellite System). Previously, the GNSS technique could be used to determine point positions by simply post-processing the data obtained by static observations. However, the intensive use of the GNSS technique has created the need for instant position determining. The GNSS method, firstly using static technique (post process), has caused the need to determine the position instantly. As a result, the classical RTK (Real Time Kinematic) was developed based on a single point and then the Network-RTK technique was developed. Today, in many countries there are networks of constant GNSS stations CORS (Continuously Operating Reference Station), which are continuously monitoring with the Network-RTK technique. In our country, there is a TNPGN-Active (CORS-TR) system, consisting of 158 stations (including 4 in the TRNC (Turkish Republic of Northern Cyprus)) on a national scale. On the local scale, there are GNSS-CORS networks that are continuously monitoring to cover their own regions established by some municipalities. These networks enable both post-process and real time coordinate generation. TNPGN-Active system allows all users to receive services from the control center., all users can get service from the control center, service can be provided all over the country, can create a base for all geographic information technologies and provide ED50 and ITRFyy datum conversion relationships. It is also used extensively in continuous monitoring and steering of land, air and sea vehicles, personally finding directions and addresses, very fast and sensitive cadastral measurement, mapping and engineering applications and geographical city and information system studies. The aim of this study is to find out whether TNPGN-Active points can be used to determine deformations in any engineering structure or earth's crust. For this purpose, a two-stage application was made. In the first stage of application, the success of the points of TNPGN-Active system in determining the crustal or structural deformations has been tried to be demonstrated. For this purpose, it has been tried to determine which magnitude deformations in any engineering structure or earth crust can be determined by using 1 second and 30 seconds data of TNPGN-Active system and it has been tried to determine what the optimum measurement period will be. Therefore, a measure mechanism has been designed which allows to determine the amount of deformation beforehand. When the results obtained from the vii measurements on the measure mechanism are examined, 6 and 12 hours measurements are sufficient to determine horizontal deformations using TNPGN-Active points but it is necessary to use 24-hours measurements in order to determine the vertical deformations. In the second stage of application, 9 stations belonging to the TNPGN-Active system selected around the NAF (North Anatolian Fault Line) were analyzed based on 7 IGS points using 10 years and 30 seconds recording interval data covering the years 2009-2018. Afterwards, it was analyzed by relative confidence ellipsoids method to determine whether there is a significant movement for consecutive years at these points. As a result of the analyzes made within the scope of the study, it was concluded that there was a significant movement in all TNPGN-active points selected on the NAF and it was concluded that these movements are compatible with TNPGN-Active point's velocities in the literature.