---
name: "asa_im_decode"
section: "1"
platform: "linux"
package: "gmtsar-core"
version: "6.5+ds-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/asa_im_decode"
---

# asa\_im\_decode(1)

asa\_im\_decode

## NAME

asa\_im\_decode - asa\_im\_decode

## SYNOPSIS

**asa\_im\_decode** *\<asa\_im\> \<asa\_ins\> \<out\> \<outType\> \<near\_range\>*

## DESCRIPTION

This program is part of GMTSAR.

\*\*\* asa\_im\_decode v1.1 by smb \*\*\*

Decodes Envisat ASAR Image Mode Level 0 data.

- asa\_im

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

- asa\_ins

  input auxiliary instrument characterization data file

- out

  output raw data file

- outType

  output file type (1=byte,4=float)

- near\_range

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

Notes:

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

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

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

auxiliary 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

\*\*\* asa\_im\_decode v1.1 by smb \*\*\*

Decodes Envisat ASAR Image Mode Level 0 data.

Usage: asa\_im\_decode \<asa\_im\> \<asa\_ins\> \<out\> \<outType\> \<near\_range\>

- asa\_im

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

- asa\_ins

  input auxiliary instrument characterization data file

- out

  output raw data file

- outType

  output file type (1=byte,4=float)

- near\_range

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

Notes:

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

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

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

auxiliary 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