To evaluate the suitability of ground penetrating radar (GPR) systems for archaeological prospection three different GPR systems with several antenna configurations were tested on one test area at the roman site Carnuntum under identical environmental conditions in 2004 (Seren et al. 2005). Due to developments in hardware and software within the last year these measurements where repeated and compared with the previous results. The data processing considers the needs of the different systems and antennas and aims to produce depth slices for best interpretation from an archaeological point of view. The results show advantages and disadvantages of the different systems and antennas, the need to process the data differently, and the necessity to increase the power of the antennas.