Minimize Current Product Information

The Envisat product strategy is to offer a simple, flexible product format and structure, featuring a unique format, as well as stripline processing and a floating scene concept. Envisat production strategy is based on:

  • a systematic processing of all acquired data into medium resolution of stripline products in order to have a reference archive with no discontinuities between pixels along track
  • child products extracted from parent products at Level 0, Level 1b or Level 2
  • a floating scene concept to allow flexibility for users to order a portion of the stripline product
  • processing of precision, high resolution products on request.

Furthermore, the number of facilities generating and using product information has been minimised to limit the effect of any changes in the contents of the product header in the application software.

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 for all Envisat products.
  • Specific Product Header (SPH) - The SPH is defined for each product and provides additional information, applicable to the whole product, related to the processing.
  • Data Set (DS) - The DS contains the instrument's scientific measurements.
  • Product Confidence Data (PCDs) - The PCD provides an evaluation of the overall quality of the product.

This chapter provides detail on all of the ASAR products and associated algorithms, including a discussion on ASAR characterisation and calibration. The details of the format for each product will be found in General Product Structure.

The specifications for the standard ASAR data products are shown in the ASAR Product Table below.  Further details are provided in the Envisat product specification.

Product ID

Product Name

Nominal resolution (m - range x azimuth)

Pixel Spacing (m)

Coverage (km - range x azimuth)

Equivalent No. Looks

IMP

Image Mode Precision

30 x 30

12.5

56-100 x 100

>3

IMS

Image Mode Single-Look Complex

9 x 6

natural

56-100 x 100

1

IMG

Image Mode High resolution ellipsoid geocoded

30 x 30

12.5

56-100 x 100

>3

IMM

Image Mode Medium resolution

150 x 150

75

56-100 x 100

40

IMB

Image Mode Browse

450 x 450

225

56-100 x 100

80

APP

Alternating Polarisation Precision Image

30 x 30

12.5

41-106 x 100

>1.8

APS

Alternating Polarisation Single-Look Complex

9 x 12

natural

41-106 x 100

1

APG

Alternating Polarisation High resolution ellipsoid geocoded

30 x 30

12.5

41-106 x 100

>1.8

APM

Alternating Polarisation Medium resolution

150 x 150

75

41-106 x 100

50

APB

Alternating Polarisation Browse

450 x 450

225

41-106 x 100

75

WSM

Wide Swath Mode Medium resolution

150 x 150

75

400x 400

11.5

WSS

Wide Swath Mode Single-Look Complex

11.5-20 x 117

7.8x80

400x 400

1

WSB

Wide Swath Mode Browse

1800 x 1800

900

400x 400

30-48

WVI

Wave Mode Imagette and power spectrum

9 x 6

natural

5 x 5

1

WVS

Wave Mode Image Spectra

-

-

5 x 5

-

WVW

Wave Mode Ocean Wave Spectra

-

-

5 x 5

-

GM1

Global Monitoring Mode  Image

1000 x 1000

500

400x 400

7-9

GMB

Global Monitoring Mode Browse

2000 - 2000

1000

400x 400

11-15

All products provided in an ENVISAT product format, provided by the ESA PF-ASAR processor.

SAR data are processed and archived by several European Processing and Archiving Centres (PACs):

  • UK-PAC  (UK)
  • D-PAC (Germany)
  • I-PAC (Italy)

A full listing of ASAR products is available in the EOLI catalogue (the Client for browsing the catalogue can be downloaded here). It should be noted that for SAR, each product ordered is reprocessed from the raw data, using the current SAR processor. There is no archive of processed products.

ASAR auxiliary data files (required to process RAW SAR data) are available  here.