Pure File Magic Area Based Editor (PFMABE): "Now view and edit your hydro, bathy and topo data in 3D. Under development by the Naval Oceanographic Office since 1998, this powerful data editing suite ingests most major sonar and lidar data types and allows for quick and easy analysis, cleaning and quality control."

http://pfmabe.software/

While "ground penetrating radar" isn't listed as a data type, it's similar to sonar. So, this software should work great with oGPR. I'm very excited about this software! I'm very happy the US Navy has released it!