Sp-461 ers-envisat Symposium

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Two-way, only mainlobe pattern measured

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Module Stepping mode

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T/R module characteristics only

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External Characterization mode over an ASAR transponder receiver

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Only transmit pattern measured

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Initially, the on-ground characterization data will be used although as variations are detected they can be compensated

for either by updating the antenna pattern characterization data in the ground processor or by modifying the on-board

antenna coefficients in the case of changes to the T/R modules nominal gains (drifts).

Rain Forest

The reasons images of the Amazonian rain forest are used for the

characterization of the antenna beam pattern are that it is a stable, large-

scale, isotropic distributed target with a relatively high backscatter and a

well-understood relationship between backscatter and incidence angle.

In order to determine the two-way beam pattern, an uncorrected rain

forest image is averaged in the azimuth direction. In the final processed

image, the inverted beam pattern is applied and hence the effect of the

pattern on the backscatter is removed.