Sentinel-1 Data Quality in Google Earth Engine

Dear friends
I am Tuyen from Vietnam. I am interested in SAR data in Google Earth Engine. As I know that if we download Sentinel-1 data for any classification, we have to do some pre-processing steps such as Apply Orbit File, Thermal Noise Removal, Radiometric and Terrain Corrections. But I am not sure if all these are pre-corrected in Google Earth Engine.

Please advise me if I have to do any pre-processing steps before I use Sentinel-1 data in Google Earth Engine?

Thank you,

Check out: