Dual Pol-InSAR Forest Height Estimation By Means Of TANDEM-X Data (original) (raw)
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TanDEM-X Pol-InSAR Performance for Forest Height Estimation
IEEE Transactions on Geoscience and Remote Sensing, 2014
TanDEM-X and TerraSAR-X platforms form together the first spaceborne single-pass polarimetric interferometer in space. This allows, for the first time, the acquisition of spaceborne polarimetric synthetic aperture radar interferometry (Pol-InSAR) data without the disturbing effect of temporal decorrelation. This paper aims to assess the potential of such data for forest applications. For this, single-and dual-pol data acquired over a boreal, a temperate, and a tropical site were investigated to characterize X-band penetration and polarization diversity of the interferometric coherence measurements. Pol-InSAR forest height inversion schemes have been proposed and implemented for the single-and dual-pol cases and cross validated against LIDAR reference measurements for all sites. The single-pol inversion relies on an external ground digital terrain model (DTM) and performed well for all sites with correlation coefficients r 2 between 0.80 and 0.98. The dual-pol inversion does not require an external DTM but depends on the visibility of the whole forest layer. Accordingly, its performance varied with forest structure and season: The best performance was achieved for the summer acquisition of the boreal test site (r 2 = 0.86) and for the winter acquisition of the temperate test site (r 2 = 0.77). For the tropical test site, only a weak correlation (r 2 = ∼0.50) could be established.
2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS, 2013
TanDEM-X (TDX) forms with TerraSAR-X (TSX) the first single-pass synthetic aperture radar (SAR) interferometer in space with polarimetric capabilities. The availability of such system allows for the first time the acquisition and analysis of X-band Pol-InSAR data from space without the disturbing effect of temporal decorrelation. After two years of mission, time series with variable baseline over the same forest sites are available, allowing to (1) explore their information content, (2) assess penetration capabilities, (3) assess scattering model assumptions, and (4) estimate vertical structure and monitor its dynamics. This paper discusses for the first time the potential of estimating forest vertical structure from spaceborne single-pass interferometers, extending classical tomographic concepts. Results of first experiments with TSX/TDX multibaseline Pol-InSAR data acquired over the Tapajos national forest (Brazil) are shown. Especially regarding tropical forests, potentials and applications of X-band for forest structure monitoring will also be discussed.
Forest Height Estimation by means of Pol-InSAR Limitations posed by Temporal Decorrelation
2009
Polarimetric Synthetic Aperture Radar (SAR) Interferometry (Pol-InSAR) is a radar remote sensing technique, based on the coherent combination of radar polarimetry (Pol-SAR) and SAR interferometry (InSAR) which is substantially more sensitive to structural parameters of forest volume scatterers (e.g. forest) than conventional interferometry or polarimetry alone. However, temporal decorrelation is probably the most critical factor towards a successful implementation of Pol-InSAR parameter inversion techniques in terms of repeat-pass InSAR scenarios. This report focuses on the quantification of the effect of temporal decorrelation at L-band as a function of temporal baseline based on multi-temporal airborne experimental data acquired in the frame of dedicated air-borne experiments. Conclusions on the suitability of ALOS/PalSAR for Pol-InSAR applications are drawn and recommendations for mission characteristics of a potential follow on mission are addressed.
Tropical-Forest-Parameter Estimation by Means of Pol-InSAR: The INDREX-II Campaign
IEEE Transactions on Geoscience and Remote Sensing, 2000
This paper addresses the potential and limitations of polarimetric synthetic aperture radar (SAR) interferometry (Pol-InSAR) inversion techniques for quantitative forest-parameter estimation in tropical forests by making use of the unique data set acquired in the frame of the second Indonesian Airborne Radar Experiment (INDREX-II) campaign-including Pol-InSAR, light detection and ranging (LIDAR), and ground measurements-over typical Southeast Asia forest formations. The performance of Pol-InSAR inversion is not only assessed primarily at L-and P-band but also at higher frequencies, namely, X-band. Critical performance parameters such as the "visibility of the ground" at L-and P-band as well as temporal decorrelation in shorttime repeat-pass interferometry are discussed and quantitatively assessed. Inversion performance is validated against LIDAR and ground measurements over different test sites.
2009
Many applications require bare-earth Digital Terrain Models (DTMs) in the presence of forest canopy. L-Band is an attractive candidate, but the derived interferometric phase represents a combination of ground and volume scattering contributions from the canopy above. The use of PolInSAR techniques, and the Random Volume Over Ground (RVOG) Model has had considerable success in model inversion studies where the objective has been to extract tree height. A major problem for the robust application of this technique is the presence of temporal decorrelation, caused by the use of repeat-pass interferometry. In this paper we will present the current results of canopy height and DTM estimation in forested areas using an experimental airborne, single-pass, L-Band PolInSAR system for which temporal decorrelation is not an issue.
Multi-baseline Pol-InSAR Forest Height Estimation in the presence of temporal decorrelation
2010
This paper addresses the effect of temporal decorrelation on the inversion of forest parameters using Pol-InSAR techniques. The modeling of temporal decorrelation and the inversion of single-baseline Pol-InSAR data in the presence of temporal decorrelation is discussed. Model based simulations and experimental multi-temporal fully polarimetric and repeat pass interferometric data from the SIR-C Space shuttle mission are used for the performance analysis of the proposed approach.
Frequency effects in Pol-InSAR forest height estimation
2006
Forest height has been related and inverted from interferometric measurements at different baselines, polarisations, frequencies. In this paper the effect of frequency on model based inversion of forest height from interferometric measurements is addressed and obtained experimental results at X, L and P Band are discussed.
Multi-baseline Pol-InSAR Forest Height Estimation in the presence of temporal decorrleation
2010
This paper addresses the effect of temporal decorrelation on the inversion of forest parameters using Pol-InSAR techniques. The modeling of temporal decorrelation and the inversion of single-baseline Pol-InSAR data in the presence of temporal decorrelation is discussed. Model based simulations and experimental multi-temporal fully polarimetric and repeat pass interferometric data from the SIR-C Space shuttle mission are used for the performance analysis of the proposed approach.
Pine forest investigation using high resolution P-band Pol-InSAR data
Remote Sensing of Environment, 2011
In this paper, a high-resolution P-band Pol-InSAR 4 data set acquired by the airborne RAMSES system over pine forest 5 stands of different height is investigated. A significant penetration 6 depth in all the polarimetric channels and a wide range of polari-7 metric-phase-center heights are observed, attesting of an interac-8 tion of the radar waves with different forest structural elements. 9 The main objective of this paper concerns forest-height inversion 10 at P-band. First, forest-modeling assumptions are evaluated us-11 ing ap r i o r iinformation, such as ground-level and forest-height 12 measurements. The full extend of the forest height is shown to 13 be responsible of the volume decorrelation, and a significant ori-14 entation effect is clearly identified over the highest stands. As a 15 consequence, the Oriented Volume over Ground model (OVoG) 16 is determined to be the most appropriated model for the 17 forest-height inversion. At P-band, the ground contribution is Q1 18 present in all the polarimetric channels due to the important 19 penetration at this frequency. To overcome this difficulty, a 20 time-frequency optimization method based on sublook decom-21 position is developed to separate the pure ground and canopy 22