Calibration of polarimetric PHARUS data
conference paper
This paper presents a procedure for the calibration of polarimetric PHARUS data, based on the JPL POLCAL
procedure, including some first results. Because the phase differences between the various polarization
channels of PHARUS turned out to be range dependent, the procedure had to be adapted by calibrating the phase
before conversion to Stokes matrix. Through this, the phase relationship between the channels could
successfully be recovered. Cross-talk was reduced to less than -30 dB. The gain imbalance, measured by
PARC responses, appeared to be high but was reduced to 0.65 dB. This relatively large uncertainty is mainly
due to differences in the antenna patterns and insufficient antenna measurements. For the same reason
the absolute calibration was not more accurate than a few dBs. Both gain imbalance and absolute calibration
will be improved by a series of antenna measurements.
procedure, including some first results. Because the phase differences between the various polarization
channels of PHARUS turned out to be range dependent, the procedure had to be adapted by calibrating the phase
before conversion to Stokes matrix. Through this, the phase relationship between the channels could
successfully be recovered. Cross-talk was reduced to less than -30 dB. The gain imbalance, measured by
PARC responses, appeared to be high but was reduced to 0.65 dB. This relatively large uncertainty is mainly
due to differences in the antenna patterns and insufficient antenna measurements. For the same reason
the absolute calibration was not more accurate than a few dBs. Both gain imbalance and absolute calibration
will be improved by a series of antenna measurements.
TNO Identifier
95078
Publisher
ESA/ESTEC
Source title
ESA CEOS SAR Workshop, ESTEC, 3-6 February 1998
Place of publication
Noordwijk
Pages
353-357
Files
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