asa_im_decode

Synopsis

asa_im_decode <asa_im> <asa_ins> <out> <outType> <near_range>

Description

asa_im_decode Decodes Envisat ASAR Image Mode Level 0 data.

asa_im_decode v1.1 by smb

Required Arguments

asa_im

Input image file(s) (multiple files if merging along-track)

asa_ins

Input auxilary instrument characterization data file

out

Output raw data file. out is a complex file with no headers (byte/float I1, byte/float Q1, byte/float I2, byte/float Q2, …)

outType

Output file type (1=byte,4=float). If outType is byte, then the decoded floats are multiplied by 127.5, shifted by 127.5, rounded to the nearest integer and limited to the range 0-255.

near_range

Near range to which to align all lines (0=use first line near range)

Notes

Starting range computed as (rank*pri+windowStartTime)*c/2 where rank is the number of pri between transmitted pulse and return echo

Calibration/noise lines are replaced with previous echo data line

Missing lines within a data set and between adjacent along-track data sets are filled with zeroes in float mode and 0.*127.5+127.5 + .5 = 128 for byte mode

Auxilary data files can be found at http://envisat.esa.int/services/auxiliary_data/asar/

Envisat ASAR Product Handbook, Issue 1.1, 1 December 2002 can be found at http://envisat.esa.int/dataproducts/asar/CNTR6-3-6.htm#eph.asar.asardf.0pASA_IM__0P

Example

asa_im_decode