EXCAVATION CAMPAIGNS FOR EVALUATING GROUND PENETRATING RADAR TO IMPROVE THE 3-DIMENSIONAL CHARACTERIZATION OF ARCHAEOLOGICAL TARGETS

Ground Penetrating Radar (GPR) is a geophysical technique for near-surface exploration and monitoring. It is an established method for investigating of archaeological sites in a fast, high-resolution, 3-dimensional and non-invasive way by using electromagnetic radiation in the microwave range to detect the reflected signals from buried objects.

As part of archaeological excavation campaigns at an important prehistorical site in Austria, Province of Styria, GPR data were collected with a Mala ProEx system and a 500 MHz antenna. Remains of the Hallstatt and early La Tène culture are dominant in this region with burial mounds, remains of ancient settlements, and smelting areas.

Such excavation campaigns provide excellent and detailed information on near-surface structures and objects and contribute better insight into the subsurface. This is crucial for understanding soil layers from archaeological and geological perspectives. Fine-grained natural deposits from the last 2000 years are making the coarse remnants respectively structures of traces of ancient civilizations easier to detect. These layers differ in propagation velocity of the electromagnetic waves and interfaces are indicated by a change of the GPR amplitude. Information collected during the excavations provide better future applications of how GPR can be enabled. Spatially located objects and layers in combination with photogrammetry data are used to calibrate the GPR and have improved data processing and interpretation.

GPR evaluation is inevitable for improving the survey and visualization of archaeological sites. This project utilizes LiDAR techniques for absolute orientation, filtering, classification, and analyzing GPR data in the form of a point cloud. This point cloud contains information about position, amplitude or classification of the point, such as, archaeological-relevant or non-relevant, and will be a benefit for a better understanding of archaeological sites. The LiDAR workflows add a facility of a 3-dimensional insight into near-surface structures. Single archaeological targets can be analyzed individually and relevant information can be preserved for future research work with the chief purpose of exploring archaeological sites without the help of an excavation.