ASAR Products and Algorithms
In general, the ENVISAT product strategy is to offer a
simple, flexible product format and structure, featuring
a unique format, as well as stripline processing and
a floating scene concept. ENVISAT product data sets will
extend over a five-year period, and will include data
from a number of instruments and operating modes
collected in continuous operation or discrete segments.
In order to handle this volume and range of data, it
is necessary to separate the data into manageable sizes
and deliver them as product files. The product strategy
is based on:
- a systematic processing of all acquired data into
medium resolution of stripline products in order to
have a reference archive with no discontinuities
between pixels along-track
- child products extracted from parent products at
Level 0, Level 1B or Level 2
- a floating scene concept to
allow flexibility for users to order a portion
of the stripline the product that fulfils their needs.
- processing of precision, high resolution products on request
Furthermore, as a design rule, the number of facilities
generating and using product information has been
minimised to limit the effect of any changes in the
contents of the product header in the application software.
The general layout for all ENVISAT includes
the following records:
Main Product Header (MPH) - The MPH
has a fixed length and the format is identical for
all ENVISAT products.
Specific Product Header (SPH) - The
SPH is defined for each product and provides
additional information, applicable to the
whole product, related to the processing.
Data Set (DS) - The DS contains the
instrument's scientific measurements.
Product Confidence Data (PCDs)
- The PCD provides an evaluation of the overall
quality of the product.
This chapter of the ASAR Handbook
will provide detail on all of the ASAR products
and associated algorithms, including a
discussion on ASAR characterisation and
calibration, as well as hints on data handling.
The details of the layouts for each product
will be found in chapter "Data Formats."(Chapter 6. )