Envisat ASAR AP Precision L1 [ASA_APP_1P]

Envisat ASAR Alternating Polarisation Mode Precision Image

How to Access Data

Users can freely access the collection using the below links and will be requested to login (new users shall register) to ESA EO Sign In to download the products. ESA internal users can use their ESAAD account.

The products are available for download via the following interfaces:

ESA EO Multimission Catalogue (EO CAT) - Allows users to discover and search products among the available datasets from ESA and Third Party Missions and instruments, using various criteria (spatial, temporal, specific).

ESA ERS and Envisat (A)SAR dedicated Online Dissemination Service - The ESA (A)SAR On-the-fly (OTF) data processing and dissemination service allows end-users to gain direct access to the (A)SAR archive from the ERS-1, ERS-2 and Envisat Missions. The data is collection based and allows data browse and download through the treeview as well as via geographical catalogue search based on area of interest and metadata. Interferometric search option is available for relevant collections. Data download is available via HTTPS, including bulk download functionality.

For information on the (A)SAR On-The-Fly service please refer to the OTF FAQ page

For further information about the EO Sign In Service visit TellUS

Should you need support please contact EOHelp



This ASAR Alternating Polarisation Mode Precision product is generated from Level 0 data collected when the instrument is in Alternating Polarisation Mode (7 possible swaths). The product contains two CO-registered images corresponding to one of the three polarisation combination submodes (HH and VV, HH and HV, VV and VH).

This is a stand-alone multi-look, ground range, narrow swath digital image generated using the SPECAN algorithm and the most up to date auxiliary information available at the time of processing. Engineering corrections and relative calibration (antenna elevation gain, range spreading loss) are applied to compensate for well-understood sources of system variability.

Generation of this product uses a technique to allow half the looks of an image to be acquired in horizontal polarisation and the other half in vertical polarisation and processed to 30-m resolution (with the exception of IS1). Absolute calibration parameters are available depending on external calibration activities and are provided in the product annotations.

Spatial Resolution: 30 m ground range x 30 m azimuth



Spatial coverage: 
90 N, -90 S, -180 W, 180 E
Temporal coverage:
2002-11-15 - 2012-04-08
Date of launch:
Mission status:
Orbit height:
800 km
Orbit type:
Swath width:
5 - 1150 km
Medium Resolution - MR (20 - 500 m)


level 1b


Utilisation of this data is subject to ESA's Earth Observation Terms and Conditions



ASAR auxiliary data
Auxiliary Data
ASAR Products Specification - Revision C
Product Specifications
Envisat ASAR Sensor Performance, Products and Algorithms
Product Information
Envisat ASAR Science and Applications
Technical Note
ASAR Product Handbook
User Manual
ASAR Product Quality Disclaimer
ASAR Products Anomalies
More ASAR Documents
Product Specifications
ASAR Software Tools
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