ASAR Products Information
The information provided in this page is applicable to the latest ASAR products.
Level 0 products are derived from the raw satellite data and are the lowest level product available. Level 1 products are then processed from L0 products. Higher level products (Level 2) can then be derived from L1 products; however, this is currently only done with Wave mode. The general layout for all products includes the following records:
- Main Product Header (MPH) - The MPH has a fixed length and the format is identical across all Envisat products.
- Specific Product Header (SPH) - The SPH is defined for each product and provides additional information related to the processing, which is applicable to the whole product.
- Data Set (DS) - The DS contains the instrument's scientific measurements that are either measurement data sets (MDS) or annotation data sets (ADS).
Further details are provided in the ASAR product specifications. All ASAR products are provided in ENVISAT format and are processed by the ESA PF-ASAR processor. For information on the latest version of PF-ASAR, see the Processor Releases page.
The specifications for the ASAR data products currently made available by ESA are shown in the ASAR Product Table below. Detailed information on all ASAR products can be found in the ASAR Product Handbook.
Product ID | Product Name | Nominal resolution (m - range x azimuth) | Pixel Spacing (m) | Coverage (km - range x azimuth) | Equivalent No. Looks |
|---|---|---|---|---|---|
IMP_1P | Image Mode Precision | 30 x 30 | 12.5 | 56-100 x 100 | >3 |
IMS_1P | Image Mode Single-Look Complex | 9 x 6 | natural | 56-100 x 100 | 1 |
IMM_1P | Image Mode Medium resolution | 150 x 150 | 75 | 56-100 x 100 | 40 |
APP_1P | Alternating Polarisation Precision Image | 30 x 30 | 12.5 | 41-106 x 100 | >1.8 |
APS_1P | Alternating Polarisation Single-Look Complex | 9 x 12 | natural | 41-106 x 100 | 1 |
APM_1P | Alternating Polarisation Medium resolution | 150 x 150 | 75 | 41-106 x 100 | 50 |
WSM_1P | Wide Swath Mode Medium resolution | 150 x 150 | 75 | 400x 400 | 11.5 |
WSS_1P | Wide Swath Mode Single-Look Complex | 11.5-20 x 117 | 7.8x80 | 400x 400 | 1 |
GM1_1P | Global Monitoring Mode Image | 1000 x 1000 | 500 | 400x 400 | 7-9 |
WVI_1P | Wave Mode Imagette and power spectrum | 9 x 6 | natural | 5 x 5 | 1 |
WVS_1P | Wave Mode Image Spectra | - | - | 5 x 5 | - |
WVW_2P | Wave Mode Ocean Wave Spectra | - | - | 5 x 5 | - |
All ASAR L0, High- and Medium resolution Level 1 imagery data products are made available through the ESA (A)SAR Online Dissemination Service (OTF).
L1 and L2 ASAR Wave products are accessible from the ESA Dissharm FTP server after specific product registration.
The data are freely available to ESA EO Sign In registered users.
High Resolution products
High resolution products are processed from the Level 0 data upon request using the (A)SAR On-The-Fly (OTF) service launched in September 2016. These products are not archived but are processed when a product is selected, usually becoming available within a few minutes. The Level 1 products processed in this manner are:
Although nominally only L1 products are made available, limited amounts of the following Level 0 (L0) products are available for direct download upon submission and approval of a data service request:
- ASA_IM__0P
- ASA_AP_0P (including Co-polar (APC), Cross-polar horizontal (APH) and Cross-polar vertical (APV)
- ASA_WS__0P
Medium Resolution products
The ASAR medium resolution Level 1 products have been processed from the Level 0 data during a bulk processing activity. Therefore, also these products have been archived and are available for direct download through the ESA (A)SAR Online Dissemination Service. The products available in this manner are:
Once registered, users can access the Level 1 OTF standard service using the ESA (A)SAR Online Dissemination Service
To download the products users will need to log in using their ESA EO Sign In account. For more details on the service, please see the links for the Data Descriptions of interest and the (A)SAR Online Dissemination Service FAQ page.
Wave products
Wave products were processed operationally using the version of PF-ASAR available at the time of processing. Therefore, these products have been archived and are available for immediate download. The products available in this manner are:
Once registered, users can access the Level 1 and Level 2 wave products though the ESA Dissharm FTP server (envwave-ftp-ds.eo.esa.int) using the credentials provided at registration.
Information on ASAR Wave Mode data can be found in the 'Envisat ASAR Wave Mode Product Description and Reconstruction Procedure' document. The purpose of this document is to provide the user community with information to reconstruct and interpret the ocean wave spectral information within the ASAR WV products.