PolInSAR for Forest – Radar Remote Sensing of Boreal Forest
Polarimetric SAR interferometry combines radar polarimetry and interferometry and allows locating scattering mechanisms as a function of relative altitude. Applications of polarimetric interferometry include for example forest height estimation and advanced 3D techniques like interferometric SAR coherence tomography. Recently, fully polarimetric SAR instruments have been attached onto satellite platforms, which rapidly made available large amounts of PolInSAR data.
Figure 1. Left: Dornier aircraft equipped with the DLR E-SAR system. Right: Bell helicopter equipped with the Aalto University’s HUTSCAT profiling scatterometer.
Figure 2. Tree height map derived with Polarimetric Interferometry.
Our team has worked in this research field for several years. The research was started in 2003 when a PolInSAR measurement campaign was organized in Finland, in close co-operation with the DLR (German Aerospace Center, Microwaves and Radar Institute, Institute of Radar Remote Sensing). In cooperation with DLR, the team has validated POLinSAR methods for boreal forest height retrieval and has proposed a method for retrieval of forest height with single polarization X-band SAR and a supplementary ground model. The group has worked also with SAR coherence tomography in forest.
Figure 3. Tree height derived from E-SAR measurements with PolInSAR techniques compared to HUTSCAT scatterometer measured forest profiles. Top: HUTSCAT profile with estimated ground line and tree top measurement. Middle: Same profile with L-band derived tree height. Bottom: X-band tree height inversion results on top of HUTSCAT profile. The x-axis is HUTSCAT sample number and the y-axis is HUTSCAT vertical range.
Cooperation partners: DLR, VTT, FGI
Recent publications:
- J. Praks, F. Kugler, K. Papathanassiou, I. Hajnsek, M. Hallikainen, “Height estimation of boreal forest: interferometric model based inversion at L- and X-band versus HUTSCAT profiling scatterometer,” IEEE Geoscience and Remote Sensing Letters, vol. 4, no. 3, pp. 466–470, July 2007.
- J. Praks, O. Antropov, M. Hallikainen, “LIDAR aided polarimetric SAR interferometry studies in boreal forest: phase center and extinction coefficient at X- and L-band,” IEEE Transactions on Geoscience and Remote Sensing, Accepted for publication, December 2011.
- J. Praks, F. Kugler, J. Hyyppa, K. Papathanassiou, and M. Hallikainen, “SAR coherence tomography for boreal forest with aid of laser measurements,” Proc. IEEE Geoscience and Remote Sensing Symposium 2008 (IGARSS’08), vol. 2, pp. 469–472, Boston, USA, 7-11 July 2008.