Speaker
Description
Synthetic Aperture Radar tomography (TomoSAR) provides a powerful framework for retrieving the vertical distribution of radar scattering within forest canopies. P-band observations are particularly attractive for forest applications because of their ability to deeply penetrate the vegetation layer, allowing to sense both canopy and ground contributions. While TomoSAR imaging has been extensively investigated from both spaceborne and airborne platforms, recent advances in radar miniaturization components have opened new possibilities for 3D imaging from lightweight unmanned aerial vehicles (UAVs). Such platforms combine flexible deployment, reduced operational cost and make easier to repeatedly acquire the same area, making them particularly suitable for multi-pass and multi-temporal observations of forest environments.
This work investigates the potential of the ONERA SAR-Light UAV-borne P-band SAR system for multi-pass forest tomography. The fully polarimetric system operates at a central frequency of 855MHz with a bandwidth of 600MHz. A dedicated tomographic acquisition campaign was performed in Southern France in April 2026 over a relatively dense and mature forest with an average canopy height of around 25m. Two areas were investigated, each including three types of land cover: open field, short vegetation and dense forest. A tomographic stack consists of 10 acquisitions performed along nominally parallel tracks, with a vertical and horizontal separation of about 0.7m between consecutive passes. The flight altitude was approximately 120m above the ground and the complete tomographic acquisition sequence was repeated twice over each area.
First tomographic reconstructions have been performed to retrieve the vertical distribution of radar reflectivity. Forest height estimation is compared with LiDAR reference data for validation. The three-dimensional distribution of polarimetric scattering mechanisms within the forest is also analyzed. The influence of range resolution is then studied by reducing the original 600MHz bandwidth and assessing its impact on vertical resolution and polarimetric analysis over all three investigated land-cover types.