The technique described uses the radar return from natural targets and at least one trihedral corner reflector to calibrate compressed polarimetric radar data for relative amplitude, relative phase, absolute amplitude, and system crosstalk. The crosstalk method is based on the theoretical result that, for natural targets with azimuthal symmetry, the copolarized and cross-polarized components of the scattering matrix are uncorrelated. This method does not require any external calibration targets to be deployed. Since compressed data are used, it is necessary to model the transmitting and receiving systems as reciprocal. The method is used to estimate the crosstalk parameters of the NASA/JPL aircraft for different types of terrain and for two frequencies. For the C-band systems the crosstalk is less than -20 dB for all ranges in the images. The crosstalk of the L-band system is a function of range, however, and may be as poor as -10 dB in the near range, leading to a noticeable distortion of the polarization signatures.
[1]
H. Zebker,et al.
Imaging radar polarimetry from wave synthesis
,
1986
.
[2]
D. Giuli,et al.
Polarization diversity in radars
,
1986,
Proceedings of the IEEE.
[3]
J. Zyl,et al.
On the optimum polarizations of incoherently reflected waves
,
1987
.
[4]
J. Kong,et al.
Theoretical models for polarimetric radar clutter
,
1987
.
[5]
E. S. Kasischke,et al.
A digital calibration method for synthetic aperture radar systems
,
1988
.
[6]
L. Norikane,et al.
Data volume reduction for imaging radar polarimeter
,
1989,
Digest on Antennas and Propagation Society International Symposium.