Extracting data from insitu location

I am wondering, if I can able to retrieve the backscattering sigma naught values for the locations with in-situ measurements, after speckle filtering from the Sentinel-1 image.
If it is possible then please let me know the procedure.

Probably you can use the Pixel Extraction tool. Accessible from the the menu at Raster / Export / Extract Pixel Values. It can also be used from the command line with gpt.
For the usage, please have a look at the help page: