Layer stacking sentinel-1 data with Landsat-8 data?

i want to stack sentinel- data with landsat-8 but i have two problems:

1- my sentinel-1 product is rotated 180 degrees compared to Landsat image(I think this is the same ascending and descending imaging mode.)…now how can i rotate it 180 degrees? Is it possible at all?

2- How can I georeference them and resample their pixel size so that i can stack them?

Keep in mind that the goal of layer stacking is to use it in classification.

I am a beginner in the field please tell me step by step.
thanks in advance.

The rotation of your SAR image is because of the ascending orbit in combination with the looking direction, which captures areas in the south first. Simply rotating it by 180 degrees wouldn’t be sufficient because your image is not geocoded. It can be solved with the terrain correction modules.
If you want to use it for classification I would advise to calibrate the image as well.

Both steps are explained here:

The tutorial refers to Radarsat data but the steps are the same.

As soon as your SAR data is geocoded you can use the collocation module under Raster > Geometric Operations > Collocation.
In this step you can choose one master image which defines the resolution of the stack. So resampling is also performed within this step.

Here are some great documents / tutorials if you are new to SAR remote sensing:
Introduction to SAR remote sensing
A tutorial on synthetic aperture radar


Thanks for your very precise answer…