Calibration Constant Validation


#1

Hello,

I have got calibration factor for Sentenal image… How can I validate it??

In the SNAP tools meta data file I see the factor to be 9999 dB. What does this mean…

Thank you
Regards


#2

the calibration constant should actually be given in the metadata. Did you open the S1 product with the import function?


#3

Hello, ABraun…

I have done that… This is what I am getting

Does this mean the calibration factor is 9999dB???


#4

you are right, sorry. This obviously only applies for TerraSAR-X. Maybe the sentinel calibration configuration is stored at another place in the metadata.


#5

Hello, The location of the Sentinel-1 calibration constant can be found in the product specfication document (https://sentinel.esa.int/documents/247904/1877131/Sentinel-1-Product-Specification) and is shown below:

For S1-A the absolute calibration factor has a value of 1.0 (or 0dB) while for S1-N it is 1.393 (or 1.44dB).


#6

Hello,
I appreciate your effort in helping me understand this issue…

"For S1-A the absolute calibration factor has a value of 1.0 (or 0dB) while for S1-N it is 1.393 (or 1.44dB)."

Is this applicable to GRD images.
Calibration factor = 0dB
Does this mean there is no need of calibration for the acquired image.


#7

Hi,

The same calibration constants apply to all Level 1 product types (GRD & SLC). If you wish to convert the product digital numbers (DNs) to radar cross-section yourself then I suggest you read the ESA document ‘Radiometric calibration of S1 level 1 products generated by the S-1 IPF’ which is available at https://sentinel.esa.int/documents/247904/685163/S1-Radiometric-Calibration-V1.0.pdf. Basically the product annotation includes a conversion from DN to radar cross-section. The document explains this and gives an example.


#8

Thank you so much…