Speaker
Description
SAR tomography is a remote sensing technique that uses multibaseline interferometric acquisitions to reconstruct a three-dimensional (3D) image of the target region (Fornaro 2014). An extra layer of information can be added if using fully polarimetric images, providing data on scattering mechanisms present in the resolution cell.
KAPRI is a ground-based real-aperture (RAR), frequency-modulated continuous-wave (FMCW), Ku-band radar with polarimetric capabilities. Originally designed as a standalone interferometer for ground-motion and topography retrieval (Werner 2008), the system was extended to work on bistatic regime with large bistatic angles (Stefko 2024) and recently, as a tomographic array in a multiple-input multiple-output (MIMO) configuration.
Between the 24th and 25th of February 2026, two KAPRI units were deployed on a terrace of the High Altitude Research Station of Jungfraujoch and acquired continuous data for a total of about 6h, targeting a relatively flat snow-covered area of the Jungfraufirn region (Great Aletsch Glacier). The campaign aims to reconstruct a tomographic profile of the snowpack together with expanding the newly developed tomographic pipeline into a full-polarimetric one, in order to investigate snow properties. Additionally, in-situ snow measurements were conducted for calibration purposes and to support future data interpretation.
Tomographic simulations show multiple side-lobes that result from the uneven distribution of phase centers. Thus, the preliminary tomograms of the region of interest (ROI) need to be evaluated carefully. While patterns found in the reconstructed profile might resemble different layerings, the overlapping of sidelobes might look like strong reflections such as the the transition of the snow layer to the glacier ice, making interpretation very challenging.
At the moment, the analysis of the tomographic profiles is on-going and focusing on a single polarisation channel. Next, they will be compared to summer data (no signal penetration) for a better understanding of the results. Lastly, the processing will be extended to combine all polarimetric channels.
REFERENCES
Fornaro, G. & Pascazio, V. 2014: SAR Interferometry and Tomography: Theory and Applications”, Canadian Journal of Remote Sensing, vol. 2, no. 3, pp. 1043–1117.
Stefko, M., Bernhard, P., Frey, O., and Hajnsek, I. 2024: Polarimetric Analysis of Biseasonal Monostatic and Bistatic Radar Observations of a Glacier Accumulation Zone at Ku-Band, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 17, pp. 9706–9727.
Werner, C., Strozzi, T., Wiesmann, A., and Wegmulle, U. 2008: A real-aperture radar for ground-based differential interferometry”, International Geoscience and Remote Sensing Symposium (IGARSS), vol. 3, no. 1, pp. 210–213.