Editing Envisat (section)

=== ASAR ===
ASAR (Advanced Synthetic Aperture Radar) operates in the [[C band (IEEE)|C band]] in a wide variety of modes. It can detect changes in surface heights with sub-[[millimeter]] precision. It served as a data link for [[ERS 1]] and [[ERS 2]], providing numerous functions such as observations of different [[polarization (waves)|polarities of light]] or combining different polarities, angles of incidence and spatial resolutions.
{| class="wikitable"
|-
! Mode
! Id
! Polarisation
! Incidence
! Resolution
! Swath
|-
| Alternating polarisation
| AP
| HH/VV, HH/HV, VV/VH
| 15–45°
| 30–150&nbsp;m
| 58–110&nbsp;km
|- style="background:#efefef;"
| Image
| IM
| HH, VV
| 15–45°
| 30–150&nbsp;m
| 58–110&nbsp;km
|-
| Wave
| WV
| HH, VV
|
| {{0}}400 m
| 5&nbsp;km × 5&nbsp;km
|- style="background:#efefef;"
| Suivi global (ScanSAR)
| GM
| HH, VV
|
| 1000&nbsp;m
| 405&nbsp;km
|-
| Wide Swath (ScanSAR)
| WS
| HH, VV
|
| {{0}}150&nbsp;m
| 405&nbsp;km
|}

These different types of raw data can be given several levels of treatment (suffixed to the ID of the acquisition mode: IMP, APS, and so on):
* RAW (raw data, or "Level 0"), which contains all the information necessary to create images.
* S (complex data, "Single Look Complex"), images in complex numeric form, the real and imaginary parts of the output of the compression algorithm
* P (precision image), amplified image with constant pixel width (12.5&nbsp;m for IMP)
* M (medium precision image), amplified radiometry image with a resolution greater than P
* G (geocoded image), amplified image to which simple geographical transforms have been applied to show relief.

Data capture in WV mode is unusual in that they constitute a series of 5&nbsp;km × 5&nbsp;km spaced at 100&nbsp;km.