Polarimetry: the characterisation of polarisation effects in EM scattering

This thesis is concerned with the development of a general theory for the characterisation of polarimetric scattering problems. Traditionally, two main approaches have been used in the literature: the first based on measurement of the coherent scattering matrix (Jones calculus) and the second on measurement of the wave Stokes parameters (Mueller calculus). This thesis contains three main developments which extend and complement the published work in this area: 1) The representation of nonsymmetric scattering matrices on the Poincaré sphere, using an extension of the fork analysis first introduced by Kennaugh. 2) The construction of a geometry based on the Lorentz , transformation for analysing, on the Poincaré sphere. The interaction of partially polarised waves with single targets. 3) The reformulation of polarisation scattering problems in terms of a target spinor and associated coherency matrix. This leads to the construction of a target sphere in 6 dimensions analogous to the Poincaré sphere in 3 dimensions. This new formulation also leads to the development of a decomposition theorem for dynamic targets based on the eigenvectors of the coherency matrix. This decomposition is more fundamental than that used by Huynen and the two are compared and contrasted. In order to demonstrate main features of the new theory and to highlight its importance to experimental polarimetry, a laser based optical polarimeter was constructed. Results for the measured coherency Matrix obtained for transmission through quarter and half wave plates are presented and analysed using the target spinor theory

Optimised limit for polarimetric calibration of fully polarised SAR systems

The optimised limit for polarimetric calibration of fully polarised synthetic aperture radar systems is derived by establishing an error model as a function of cross-talk, channel imbalance and system noise. Compared with noise equivalent sigma zero, the polarimetric error below the optimised limit is too small to affect the signal of cross-polarised channel. Thus, polarimetric calibration could be relaxed or even ignored in this case. With the backscatter model, optimised limits for cross-talk and channel imbalance at X, C and L-bands are presented. Moreover, when ignoring channel imbalance, the limit for cross-talk is given in a quantitative way. These results are very useful in practice, allowing significant reduction in calibration cost

A review of the applications of SAR polarimetry and polarimetric interferometry - an ESA funded study

International audienc

Coherence Optimisation in Polarimetric SAR-Interferometry

In this paper we outline a general formation for vector wave interferometry and then solve the optimisation problem involving maximisation of phase coherence. In this way we are able to show that wave polarisation effects play an important role in the extraction of information from Radar interferograms

Polarimetric Radar Interferometry.

In this paper we outline a general formulation of vector wave interferometry and then use this formulation to solve the optimisation problem for interferometric coherence. We show that this problem can be reduced to a singular value decomposition of a non-symmetric complex matrix. We then develop a stochastic scattering model for an elevated forest canopy and use it to demonstrate application of the optimisation scheme

Polarimetric Optimisation in Radar Interferometry

A general formation for vector wave interferometry is outlined and the optimisation of the phase coherence. In this way it is shown that wave polarisation effects play an important role in the extraction of information from radar interferograms

Polarimetric Effects in Radar Interferometry

We first show formally that both these important limiting factors on interferometric performance depend on the choice of wave polari- sation. We then show how the theory of conventional single image radar polarimetry has to be modified to account for such coherent multi-imagery. We then demonstrate a formulation designed to find the optimum wave polarisations of use in interferometric appli- cations