Local Incidence angle details


I am not sure if this question can be asked here or not. I am really sorry if its not appropriate
I am a newbie working on SAR calibration. I know I can find the local incedence angle using SNAP tool but is there anyother way I can find the local incedence angle theoritically.

I appreciate guidance from the forum for the same.

Sentinel 1 has a constant acquisition geometry for a given acquisition mode.

In the Sentinel-1 Products Definition file (https://sentinel.esa.int/documents/247904/1877131/Sentinel-1-Product-Definition), you can obtain the incidence angle for IW data at page 30/129 (or 3-9 (or Table 3-5))

Thank you, qglaude for the information. I am not asking particular to Sentenal data… I wanted to know a formula or method which can be used irrespective of the SAR…