Positioning systems are defined as locational, regional and global depending on their coverage. There are currently 4 global (NAVSTAR GPS, GLONASS, BeiDou and Galileo), 2 regional (NavIC and QZSS) GNSS operating around world. For Turkey, a regional system with IGSO (Inclined Geosynchronous Orbit) and GEO (Geostationary Orbit) satellites is more reasonable to establish considering cost benefit ratio. TURKSAT and TAI have already made studies on regional systems. In this context, it is aimed to design an affordable regional system based on existing GEO satellite fleet of Turkey. TURKSAT satellites positioned on 31, 42 and 50 degrees east longitudes are accepted as GEO components of the constellation. The constellation is completed with various IGSO satellite arrangements. The efficiency of proposed constellations has been examined by calculating DOP (Dilution of Precision) values for a target point in Istanbul. Except the initial constellation similar to QZSS design, 6 different scenarios has been tested. 3 QZ ground track design with equally distributed 6 satellites has been selected for minimum DOP values and maximum availability of satellite signals. DOP value results show that the proposed regional constellation can be used in all kind of reliable navigation applications.