The case study presented is a prime example of integrated geophysical-archaeological prospection. The aerial photographs available are complemented by non-destructive geomagnetic and geoelectric surveys with a reading distance of 0.5 m or less. To gain depth information and provide higher resolution, ground-penetrating radar (GPR) data are integrated. The GPR data were collected in a 0.5 ð 0.05 m raster and visualized as black-and-white time or depth slices. The developments presented allow us to incorporate GPR into the standardized interpretation process of archaeological prospection based on a geographical information system (Grs). Using GPR and all the other prospection data available as a basis, a detailed three-dimensional interpretation model of the monument detected, the southern part of the forum of the civil town of Roman Carnuntum, is created.

Traditionally, ground‐penetrating radar (GPR) measurements for near‐surface geophysical archaeological prospection are conducted with single‐channel systems using GPR antennae mounted in a cart similar to a pushchair, or towed like a sledge behind the operator. The spatial data sampling of such GPR devices for the non‐invasive detection and investigation of buried cultural heritage was, with very few exceptions, at best 25 cm in cross‐line direction of the measurement. With two or three persons participating in the fieldwork, coverage rates between a quarter hectare and half a hectare per day are common, while frequently considerably smaller survey areas at often coarse measurement spacing have been reported. Over the past years, the advent of novel multi‐channel GPR antenna array systems has permitted an enormous increase in survey efficiency and spatial sampling resolution. Using GPR antenna arrays with up to 16 channels operating in parallel, in combination with automatic positioning solutions based on real‐time kinematic global navigation satellite systems or robotic total‐stations, it has become possible to map several hectares per day with as little as 8 cm cross‐line and 4 cm in‐line GPR trace spacing. While this dramatic increase in coverage rate has a positive effect on the reduction of costs of GPR surveys, and thus its more widespread use in archaeology, the increased spatial sampling for the first time allows for the high‐resolution imaging of relatively small archaeological structures, such as for example 25 cm wide post‐holes of Iron Age buildings or the brick pillars of Roman floor heating systems, permitting much improved archaeological interpretations of the collected data. We present the state‐of‐the‐art in large‐scale high‐resolution archaeological GPR prospection, covering hardware and software technology and fieldwork methodology as well as the closely related issues of processing and interpretation of the huge data sets. Application examples from selected European archaeological sites illustrate the progress made.

The launch of the first German radar satellite TerraSAR-X in 2007 opened a new era in spaceborne radar remote sensing. So far the applicability for the high-resolution prospection of upstanding and, especially, buried monuments was limited because of the low resolution of the former sensors. TerraSAR-X, however, provides us with images with a spatial resolution of up to 1 m. The satellite operates in the so-called X-band with a frequency of 9.65 GHz. Therefore it is supposed that there is no possibility to penetrate the soil with this sensor. To testify and analyse the benefit of TerraSAR-X in archaeological geophysics, we chose as a test site a Roman fortress in Syria. The site was chosen as we already have GPR data of the same area for a comparison and for the verification of the actual penetration depth. Our results revealed that it is possible to resolve superficial and even buried structures in the data set, which provides evidence that the X-band waves can penetrate the soil. This paper shows our results of the survey and an estimation of the possible penetration depth of TerraSAR-X. Copyright

Summary Recently, the unique foundations of a school of gladiators were discovered in the Roman town of Carnuntum (40 km southeast of Vienna, Austria) by applying a combination of non‐invasive archaeological prospection techniques such as magnetometry, ground penetrating radar, aerial photography, airborne laser scanning and airborne imaging spectroscopy. Although the well‐preserved remains of the building complex were revealed down to a depth of 1.8 m by high‐resolution near‐surface geophysics, some questions about the surrounding soil landscape remained unanswered. Therefore, a proximal soil sensing procedure based on a survey with a multi‐receiver electromagnetic induction (EMI) instrument was conducted to interpret the surroundings of the school, covering an area of 5.6 ha. We investigated the usefulness of integrating the complementary apparent electrical conductivity (ECa) and apparent magnetic susceptibility (MSa) measurements for the mapping and investigation of this soil landscape. The multiple ECa measurements allowed the identification of zones with low‐conductive gravel outcrops, and zones where silty‐clayey soils were deposited on top of the underlying gravel. An EC‐depth slicing procedure enhanced the contrast between small soil features, such as frost‐wedge pseudomorphs and drainage gullies, and their background, and provided indications about the depth extent of these features. The MS‐depth slices showed the foundations of the school of gladiators, an aqueduct and grave monuments. After combining these results with the topography, an integrated visualization of the school in its soil landscape was obtained. This study demonstrated the potential of multi‐receiver EMI soil surveys to map and interpret the soil landscape and to discern small natural as well as archaeological features.

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