  Remote sensing for archaeological investigations using surface response is
reasonably well established, however, remote subsurface exploration is limited
by depth and penetration and ground resolution. Furthermore, the conservation
of archaeological sites requires constant monitoring capability, which is often
not feasible between annual field seasons, but may be provided by modern
satellite coverage. Here we develop an approach using Sentinel-1 C-band radar
backscatter, and Sentinel-2 multispectral data, to map and characterise the
site of Qubbet el-Hawa, Egypt. The multispectral bands analysed show similar
sensitivity to satellite imagery. However, the radar backscatter is sensitive
to exposed known structures, as well as disturbances to soil
textural/composition profile due to excavation/erosion. Sub-resolution features
such as causeways manifest as a 'radar-break' in the backscatter - a
discontinuity in otherwise continuous radar units. Furthermore, the finite
subsurface response in the backscatter under the arid conditions of the site
means we are able to delineate some shallow subsurface structures and map their
orientation beneath the surface in areas not yet excavated. The sensitivity of
Sentinel-1 backscatter to soil disturbance and human activity at Qubbet
el-Hawa, and the short (~12 day) recurrence time of the satellites, makes it an
important tool in heritage conservation.
