The S1A toolbox cannot perform focusing of the Sentinel Level-0 data. But the resolution of the free image is a little low to perform some scientific research. I want to get some full-resolution image and how can I focus the raw data?
SLC images are full-resolution but unless you do InSAR you will probably be happier with IW GRDH as it’s a much simpler product. For focusing you would need to use a SAR processor but I don’t think any of the free solutions can focus TOPS-mode data at the moment.