Deriving Forest Canopy Height Models using multi-beam TerraSAR-X Imagery

The presented study focuses on the derivation and validation of digital surface models and digital forest canopy height models using multi-beam TerraSAR-X Spotlight data. The derivation of these elevation models is based on multi-image radargrammetry and the validation is based on a comparison to laser scanner DSM and DTM. It is shown that the resulting DSMs are very accurate (+/- 1 meter) on bare ground, while forest canopy heights are systematically underestimated. This bias is caused as the SAR signal in X-band penetrates into the forest canopy, where the penetration depth depends on the off-nadir look angle.