GeoHammer
SPH Engineering's GeoHammer suite — free, Pro and cloud-hosted tiers for processing GPR and CSV survey data in the field or back at the office.
Software

GeoHammer data processing software (free version)
Free, full-featured build of SPH Engineering's field GPR/CSV data tool — everything in GeoHammer Pro except GeoTIFF and KML export.

GeoHammer Pro data processing software
Licensed GeoHammer build adding GeoTIFF/KML export and a year of vendor support to the free processing toolset.

GeoHammer Pro data processing software (cloud access)
The same GeoHammer Pro processing engine, accessed pay-as-you-go through GeoCloud instead of a local install.