Polarimetric calibration of circularly polarized synthetic aperture radar data

Autor: Douglas A. Gray, Alvin S. Goh, Mark Preiss, Paul Pincus
Rok vydání: 2017
Předmět:
Zdroj: IEEE Transactions on Geoscience and Remote Sensing. 55:6824-6839
ISSN: 1558-0644
0196-2892
DOI: 10.1109/tgrs.2017.2734924
Popis: Two novel aspects of polarimetric calibration for fully polarimetric imaging radar systems are addressed. First, the radar system model is formulated in the context of two generic transmitter designs, either a single amplifier followed by a high-power switch or a low-power switch followed by two amplifiers. In the latter case, it is shown that a particular factorization of the polarimetric distortion matrix leads to a significant simplification of the cross-talk representation, from the standard four parameters to two reciprocal parameters, one for each of the antennas. Various system models from the literature are thus placed in a unified framework. Second, calibration techniques for circularly polarized antennas are derived, using either corner reflectors or clutter. However, where standard linear-basis algorithms estimate the cross-talk by its first-order distortion of reflection-symmetric clutter, no equivalent algorithm has been found for the circular basis; indeed, it is shown that the distortion caused, to first-order, by circular-basis cross-talk does not permit the individual cross-talk parameters to be identified. The calibration techniques are applied to fully polarimetric data acquired by the Ingara L-band radar using left- and right-polarized helical antennas.
Databáze: OpenAIRE