Subsurface imaging with low frequency SAR. Field validation in France and Egypt using a ground-penetrating radar

G. Grandjean, P. Paillou, N. Baghdadi, E. Heggy, T. August, Jose Achache

Research output: Contribution to journalArticle


We study the capabilities of low frequency radar systems to sound the subsurface in arid countries. This approach is based on the coupling between two complementary radar techniques: the airborne Synthetic Aperture Radar (SAR) used in L-band (1.2 GHz) for imaging large scale subsurface structures, and the Ground-Penetrating Radar (GPR) used between 500 and 900 MHz for sounding soils at a local scale, from the surface down to several meters. In this paper, we first recall the results obtained on the Pyla dune (France). This site is a bare sandy area presenting large subsurface structures (paleosoils) at varying depths. A polarimetric analysis of airborne SAR data, as well as the GPR sounding experiment, shows that subsurface scattering occurs at several places. The SAR penetration depth is estimated by inverting a simple scattering model for which the subsurface structure, i.e. geometric and dielectric properties, is determined by the GPR data analysis. The recent results obtained on the well-known site of Bit Safsaf (southern Egypt) are then presented. The comparison between L-band SAR and GPR sections shows that penetration effects occur in many places, revealing rich subsurface structures. These results suggest that airborne radar systems in a lower frequency range (P-L band) should be able to detect soil structures down to several meters, leading to innovative Earth observation systems for geological and hydrogeological mapping in arid regions.

Original languageEnglish
Pages (from-to)217-222
Number of pages6
JournalProceedings of SPIE-The International Society for Optical Engineering
Publication statusPublished - 1 Jan 2002



  • Airborne SAR
  • Ground-penetrating radar
  • Low frequency radar
  • Penetration in soils

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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