Since 1994 the Alfred Wegener Institute (AWI) maps with ski-equipped research aircraft ice thickness and internal structure of the Antarctic ice sheet using radio-echo sounding (RES) beside other parameters such as magnetics and gravity. In October 2007 AWI took a new aircraft into service, of type Basler BT-67, named POLAR 5. The large range of the aircraft and its capability to start a high elevations, allowed for the first time to map ice sheet properties between all major deep ice core drill sites in East Antarctica while operating from existing stations. Because ice is transparent for electromagnetic waves in the frequency range of 1-300 MHz it is possible to detect ice thickness and internal structure of ice sheets using RES. By tracing internal horizons it is possible to transfer age-depth scales from one drill site to another. This allows to identify, synchronize and thus to compare corresponding parts of ice cores independent of their individual model based dating. During the IPY, in austral season 2007/08, POLAR 5 was operated from French-Italian station Concordia on the East Antarctic plateau for the survey Dome Connection East Antarctica (DoCo). Within three days of flying the deep ice core drill sites Talos Dome, Dome C, Vostok, and the summit area of Dome A have been connected with high resolution RES profiles. At Dome A another deep ice core will be established in near future. The combined profiles allow for the first time, a synchronization and comparison of the deep ice cores independent of their dating and gives an estimate for the future drill site. The presentation will focus the internal structure and the subglacial bed of the ice sheet between the drill sites. Furthermore, the individual age-depth scales of the ice cores will be compared, by using the extracted RES layers.