Minimize AVNIR-2 Products and Algorithms
Minimize Products Information

ALOS products follow the standard CEOS format convention. The detailed product format specifications have been defined and are maintained by JAXA and are available here. Products provided by ADEN are generated using the JAXA processor, integrated in the ADEN ground segment. Therefore, product format and auxiliary information provided in the product (product coordinates, calibration parameters, etc.) are those defined by JAXA. 

 

Level

Definition

Option

Note

 0   -   -  This data is not currently made available to users.

1A

Uncompressed, reconstructed digital counts appended with radiometric calibration coefficients and geometric correction coefficients (appended but not applied)

 

Separate image files for each band

1B1

Radiometrically calibrated data at sensor input

 

Separate image files for each band

1B2

The following correction options are available: R: Geo-reference data; G: Geo-corded data; D: Rough DEM (Digital Elevation Model) correction: this option corrects the topographical influence to the areas where DEM was covered. DEM correction is effective only in Japanese region. There is a possibility that DEM correction error will occur when pointing angle is large. In this case, accuracy is not guaranteed because interpolation is carried out in the error area. If specifying this option outside the Japanese region, D option becomes effective, however, DEM applied product is not generated. That is; the product, which is defined as altitude = 0m, will be generated.

Map-Projection:

UTM,

Polar Stereographic

Resampling:

Nearest Neighbour

Cubic Convolution

Bi-Linear

Separate image

files for each band

 

 

 

Note these original products originating from the ALOS Data European Node (ADEN) were processed using the JAXA processor integrated into the ADEN ground segment. Therefore, the product format and auxiliary information provided in these original products (incl. product coordinates, calibration parameters, etc.) are those defined by JAXA.

  • AVNIR-2 Product Characteristics
  • Level 1A is not calibrated.
  • A summary file (ASCII file) is provided with all data processed. This ASCII file embeds basic information on product metadata.
  • Pixel spacing, to be applied for transformation from level 1B1 to level 1B2, is strongly dependent on the pointing angle of the AVNIR-2 instrument when observing the area of interest. This parameter is fixed by the processor based on the following pointing angles:

Pointing angle

0 to 31.6 degrees

angle 31.6 to 40.3 degrees

More than 40.3 degrees

Pixel spacing (m)

10

15

20

  • Radiometric rescaling gain and offset values for each band are expressed in W/m2str­m and can be retrieved from products processed into CEOS format. These values are stored in the scene header record. It should be noted that the processing chain applies a pre-flight calibration and the coefficients have been determined before launch. No in-flight calibration was applied.
  • Solar spectral irradiance values are not provided with the products processed into CEOS format. They can be computed using the following values (Thuillier 2003):

Band

Band 1

Band 2

Band 3

Band 4

Central
Wavelength
(nm)

463

560

652.1

820.6

Solar spectral
irradiance
(W/m2/_m)

1943.3

1813.7

1562.3

1076.5

 

  • For the projection parameter, users can choose between UTM or Polar Stereographic. The projection parameters are fixed by the processor. The Polar stereographic parameter corresponds to the latitude/longitude of the scene centre.
  • Rational  Polynomial Coefficients (RPC) are not provided with the product format. If users want to apply map projection; to transform geo referenced product to geo coded product, they  need to use the polynomial coefficients provided with the CEOS format.
     
  • Product Availability
  • To search and browse the available AVNIR-2 products in the ADEN archives, please refer to ESA Simple Online Catalogue. Searching is possible without registration; ordering is only possible for registered users.