RGPR is a free and open-source software (https://emanuelhuber.github.io/RGPR/) for ground-penetrating radar (GPR) data processing.
I've had some interactions with Emanuel, the developer of RGPR. He's really responsive despite being busy. I used R for quantitative analyses for my PhD so I was really pleased to find the RGPR package. I'm currently working on a Shiny web app to produce a graphical interface for the functions and it's going fairly well!