G.P.R. imaging capabilities: the experience in the "Laurentina" archaeological test site

A G.P.R. survey was recently carried out in the «Laurentina - Acqua acetosa» archaeological site near Rome. The aim of the survey was two fold: assessing the potential capabilities of this geophysical technique as related to data acquisition, processing and interpretation; developing a strategy to investigate archaeological sites. According to an existing map of the buried ruins, derived from the site excavation, it was possible to evaluate the real imaging power of G.P.R. As a matter of fact all the archaeological structures were clearly outlined by radar images in the G.P.R. response. In addition other strong reflectors, due to excavation activity, were accurately mapped. Data acquisition was designed to develop a strict comparison of various sets of instruments. 300-400 MHz single antennas and 500 MHz antenna arrays were carefully tested in the field to optil1lize the acquisition parameters and estimate an initial e.m. response. A strong data processing was an heavy but necessary step in order to properly enhance the e.m. response of walls and pavements. The effectiveness of the processing algorithms results in a definite improvement of the radar image quality, expecially of the excavated trench bottom signatures. Clutter frequency of the heterogeneous subsurface were worked out utilizing multi-frequency antennas. All these G.P.R. examples clearly exhibit a difference of resolving power between raw and processed data. A 3D arrangement and display can further enhance radar results and improve the final section interpretability.