Operating in C-band, S1A’s stripmap products achieve
spatial resolutions better than 5m (Table 5-1 in [1]).
Especially in light of the increasing need for SAR timeseries and combination of S1A data with other data sources,
S1A products are expected to provide equally high and
consistent geolocation accuracy. The S1A ground segment
includes several groups providing scientific expertise and
engineering support during the mission’s commissioning
phase [4]. As one of these groups, the SAR team at the
Remote Sensing Laboratories, University of Zurich,
Switzerland is responsible for the S1A product geometric
calibration and validation. At the time of this writing (end of
May, 2014), S1A has not yet reached its final reference
orbit; this will be achieved within 1-2 months. Early
calibration issues and ongoing orbital manoeuvres have
presented a challenge to the generation of SAR products
with consistently high geolocation accuracy. However, in
spite of these challenges, product geolocation estimates have
been improving steadily.