Anthony Freeman

Learn More
An approach has been developed that involves the fit of a combination of three simple scattering mechanisms to polarimetric SAR observations. The mechanisms are canopy scatter from a cloud of randomly oriented dipoles, evenor double-bounce scatter from a pair of orthogonal surfaces with different dielectric constants and Bragg scatter from a moderately(More)
Two simple scattering mechanisms are fitted to polarimetric SAR observations of forests. The mechanisms are canopy scatter from a reciprocal medium with azimuthal symmetry, and a ground scatter term, which can represent double-bounce scatter from a pair of orthogonal surfaces with different dielectric constants or Bragg scatter from a moderately rough(More)
A model for linearly polarized fully polarimetric backscatter measurements is used, incorporating the effects of system noise, channel amplitude, phase imbalance, crosstalk, and Faraday rotation. A step-by-step procedure is outlined for correction (or calibration) of fully polarimetric data subject to Faraday rotation, to recover the true scattering matrix.(More)
The potentially measurable effects of Faraday rotation on linearly polarized backscatter measurements from space are addressed. Single-polarized, dual-polarized, and quad-polarized backscatter measurements subject to Faraday rotation are first modeled. Then, the impacts are assessed using L-band polarimetric synthetic aperture radar (SAR) data. Due to(More)
Tandem-L is a proposal for an innovative interferometric and polarimetric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important mission objectives are global forest height and biomass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of(More)
During the two different overflights of t he Bonanza Creek Exper imenta l Fores t ( n e a r Fa i rbanks , Alaska) by t h e NASA/JPL r a d a r po la r ime te r in M a r c h 1988, t h e envi ronmental condi t ions over t he region changed significantly with tempe ra tu res ranging f r o m unseasonably w a r m (1 t o 9°C) d u r i n g one day t o well below(More)
The purpose of this paper is to analyse and quantify the topographic effects on the antenna gain pattern correction of existing spaceborne Synthetic Aperture Radar systems, namely ERS-1, JERS-1, SIR-C, and X-SAR. Simulations and real SAR data of a test site are used. The corrections are carried out taking into account the local surface topography and(More)