184 research outputs found
The Glen Affric radar project: forest mapping using polarimetric interferometry
No full textIn this paper we describe the Glen Affric
radar project, a multi-disciplinary program addressing
the ability of polarimetric radar interferometry to
provide quantitative vegetation structural information of
importance in forest mapping and ecology studies
The Glen Affric radar project: investigating applications of polarimetric SAR interferometry
No full textSAR Coherence Tomography For Boreal Forest With Aid of Laser Measurements
No full textIn this paper we evaluate X- and L-band SAR coherence tomography
in boreal forest with the help of detailed digital terrain
and canopy height models, produced by laser scanning.
Polarimetric coherence tomography (PCT) needs accurate estimates
of ground phase and tree height. Supplemental accurate
elevation models allow us to evaluate the performance
of PCT in normal case when initial values are derived from
RVoG model inversion and provides opportunity to use PCT
for nonpolarimetric data. The work is based on E-SAR Lband
and X-band measurements in Finland. Our results show
that with accurate elevation and tree height information single
polarizationX-band coherence tomography is feasible and
works well. Accurate ground elevation information improves
also the performance of fully polarimetric repeat pass L-band
PCT. The laser DEM provides better ground phase estimate
than RVoGmodel inversion in the presence of temporal decorrelation.
Our results show that accurate ground phase estimation
ismore critical for successful coherence tomography than
other parameters
Transient excitation of a layered dielectric medium by a pulsed electric dipole: spectral representation
No full textSpectral methods are the obvious choice for modeling the transient excitation
of a continuously layered, plane-stratified dielectric halfspace. Such methods typically
involve an inverse spatial Fourier transformation and the evaluation of the constituents.
In this paper, we consider the spectral representation. The idea is to normalize the
spatial wavenumber with respect to frequency. Compared with the Cagniard-De Hoop
method, our approach is different in the sense that we keep the frequency real, and
allow the time variable to become complex. In this respect, our work also resembles
she spectral theory of transients.
We restrict the temporal Fourier inversion to nonnegative frequencies by expressing
the time-domain signal as the real part of a dual analytic signal. Reversing the order
of the temporal and spatial Fourier inversions then leads to the so-called time-domain
Weyl representation for the reflected field. In this representation, accumulated guidedwave
poles give rise to an additional branch cut. The representation thus obtained is
used to derive a suitable combination of Gaussian quadrature rules for the evaluation
of the spectral integral
Recent Developments and Applications of Multi-Pass Airborne Interferometric SAR using the E-SAR System
No full textAirborne SAR systems are traditionally considered to be a suitable testbed for the demonstration of new Earth observation
data acquisition techniques and for the development of new applications based on the acquired multi parameter data sets.
Spaceborne SAR system concepts and mission design is based on the experience gathered from these airborne SAR
experiments and from dedicated campaigns. DLR's E-SAR system is supporting these activities since the late 1980-ties
by providing high resolution multi-frequency and multi-polarisation data sets to a large user community. Triggered by the
scientific needs and also by the recent advancements in motion compensation techniques several new operating modes are
now available for the E-SAR system on a quasi-operational basis. This paper gives an overview of these techniques and
presents novel application examples
A new method for characterizing depolarization effects in radar and optical remote sensing
No full text
- …
