ASAR Wide Swath Mode Single Look Complex Products
To date, the only operational Level-1B data product
offered by ESA from the ASAR Wide-Swath Mode (WSM) has been the multi-look
detected product (ASA_WSM_1P), intended to support applications that exploit
In order to support the development of new applications
with the ASAR ScanSAR data, a new WSM product providing phase information has
been developed and implemented in the ESA ASAR processor, the Wide-Swath
Single-Look complex product (ASA_WSS_1P). It is expected that this new product
will be mainly used for INSAR applications based either on wide-swath/wide-swath
pairs or wide-swath/image mode pairs, applications of ocean current mapping,
large-area ocean wave retrievals, and atmospheric water vapour characterisation.
It shall be mentioned that the standard ESA WSS product is based on the
prototype WSS processor developed by Polimi/Poliba, which has also been used to
generate prototype products for testing the potential and preparing the
exploitation of the new WSS product (see the first ASAR WSM-WSM interferogram).
The new ESA ASA_WSS_1P product is
now available as standard ENVISAT ASAR product and it can be ordered using
EOLI-SA. Please contact firstname.lastname@example.org for
The ASA_WSS_1P product format is slightly different
from other ASAR products since:
characteristics of the ASA_WSS_1P product are summarised below:
- there are 5 different MDSs, one per sub-swath
- a "Doppler Grid" ADS has been included to support ocean current mapping
- there are 5 records in the MPP ADS, one per sub-swath
- there are 5 records in the SQ ADS, one per sub-swath
A detailed description of the WSS
product format can be found in the "ENVISAT-1 Product Format Specifications.
Volume 8: ASAR Products Specifications" (PO-RS-MDA-2009, Is.4, Rev.A, 11/05/2004, http://earth.esa.int/pub/ESA_DOC/ENVISAT/ASAR/ASAR_productspecs_issue4A.pdf).
- processing is fully phase preserving
- data in the MDSs is sampled in a common grid both in range and in azimuth
- standard product is 60 sec long with 80 m az. pixel spacing
- auxiliary timeline information has been added in the Main Processing
- elevation antenna pattern correction is applied by default (although the
product is a single-look complex)
Some additional information regarding the ASA_WSS_1P characteristics
applications can be found in
the paper presenting the new products at the ENVISAT Symposium
The potential of Wide-Swath Complex products for estimating ocean surface velocity is thoroughly
Details regarding the use of Wide Swath Single-Look complex products
for interferometric applications can be found in the presentation from Poliba/Polimi at the ENVISAT Symposium 2004.
Wide Swath Single Look complex products were used for the
interferometric analysis over BAM after the earthquake in December 2003.
Interferometric results using WSM data and comparison with the standard results
using only Image Mode data can be found here.
In addition, some results on the use of ScanSAR interferometry for
atmospheric parameter estimation are available here.