3.1.3 Internal Data Flow
ASAR Data Processing
All of the ASAR modes of operation
are processed on the ASAR Generic Processor to
be installed in the ESA Payload Data
Handling Stations (PDHS), at Kiruna and
ESRIN-Frascati, and to be procured by the
ENVISAT Processing and Archiving Centres (PACs)
and national stations offering ESA ASAR
services. The use of a generic processor will
ensure product compatibility between the
different processing centres (same format
and processing algorithm) and will simplify
The ASAR generic processor runs on
an IBM SP-2 parallel computer system and is
designed to ensure a throughput linearly
proportional to the number of processing nodes
available in the station.
The key feature of the ASAR Generic
Processor is the capability to process acquired
data to generate medium-resolution products
(150 m) or low-resolution product (1 km), and
their corresponding browse products, in
Stripline without geometric or radiometric discontinuity.
The ASAR ground processor
functional block diagram is shown below in
|Figure 3.20 ASAR ground processor functional block diagram
ASAR User Services
The access to user services is provided via the
Internet and it includes, in particular, a free
access to all browse images and the
capability to access the data inventory.
The user services allow ordering of products from
acquired data and the ordering of future
products to be acquired. The on-line
retrieval of small products is also possible.
The delivery of products is performed in Near
Real Time (NRT) via satellite links and off-line
on physical media.
For a full discussion of the ASAR products, and
the processes that produce them, refer to the "Products and
Algorithms"(Chapter 2. ) section of this handbook.