·         Determination of station locations

·         Determining CORS network GPS receivers

·         Determining CORS network software

·         Determining CORS control center

·         Determining power and communication requirements (electric, phone, internet etc.)

are some of the subjects.

Goal is to determine RTK locations throughout Turkey, with the help of the CORS-TR project. In the CORS-TR network RTK coverage is expected to be 75km from the nearest station. In accordance, CORS locations every 100-150km are being considered. CORS-TR will be mostly utilized in urban areas. In addition, when energy, communication and similar requirements are considered, following criteria will be essential while selecting CORS station locations.

·         City centers

·         Large population areas near borders and shore lines

·         Sturdy ground (out of landslide zone)

·         Existence of power and communication

In addition selecting locations that will help observing tectonic plate movements will be high priority.

Main specifications that will be considered while selecting CORS GPS receivers for CORS-TR are the following:

·         Double frequency GPS receivers and choke-ring antenna

·         Ability to process GPS, GLONASS and GALILEO signals that will be in service in the near future

·         Web based

·         Open to all types of communication techniques (radio, GSM / GPRS, Thuraya, NTRIP, Internet, …)

There are companies like Leica, Thales, Topcon and Trimble that are capable of providing such systems. System selection will be done by considering receiver technical capability, company adequacy, support and price.

For CORS software the main requirement will be the ability to calculate ionosphere, troposphere, multipath and orbit modifications and RTK location up to 75 km. Selected software will be at least capable of both of the wide spread techniques. These techniques,

·         FKP (Flachen Korrectur Parameter) – Linear area correction parameters

·         VRS (Virtual Reference Stations) – Virtual Reference Stations

Administration of the CORS-TR will be handled from a central location. All CORS-TR station data will be transmitted to this center and CORS network calculations and corrections will be served from this location.  Consideration of deploying centers for regions is also in the project scope.

For communication RTCM 3.0 and higher protocols will be used. Thus including radio, GSM, GPRS, NTRIP (Network Transport of RTCM via Internet Protocol) communication will be provided. GSM Coverage throughout country (Turkcell, Telsim, Avea .. ) will be determined and Thuraya usage will be researched for the areas out of coverage.

All work in this part is planned to finish by the end of 2006.

Sturdy government building roofs, meteorology station areas and other areas with protection and communication are being considered for CORS-TR.

After CORS receiver facilities are constructed, receivers will be deployed and CORS-TR will start serving. As mentioned before all data will be collected to a central location automatically and post-processing, DGPS and RTK services will be provided to users.

During initial applications of the project, CORS-TR center will be formed in ?stanbul as part of ?KÜ and system will be started and become functional. Similar centers will be formed by HGK and TKGM as well.

Until recently ED50 datum (Me?eda?, Ankara) have been used in our country and all geodesic networks, maps and scales were created on this datum. Said National Geodesic Network (UJA) work was started by HGK between 1950 and 1954 and with later densifications 449215 points were assigned. Because of the limited technology of the time which these points were assigned, they have UJA 1/100000 – 1/50000 (10-20ppm) relative precision (1.0 – 2.0m error in 100km base)