About the Instrument

We use a GSSI UtilityScan GPR with 350 MHz frequency antenna and depth penetration up to 10 meters. The GPR is retrofitted with a Model 626 3-wheel cart for handling in grassy areas and uneven terrain.  The unit is also equipped with a real-time kinematic GPS unit for simultaneous GPS and GPR collection.

Post-processing of data is completed in Radan-7 and ArchaeoFusion, an open source geophysical data processing software from the University of Arkansas. 

Four main post-processing steps are conducted:

1. Time zero correction to adjust for surface reflection 
2. Background removal to reduce horizontal background noise
3. Filtering to remove high and low-frequency noise
4. Migration to reduce hyperbolic reflection

Finished raster outputs are exported as time slices and geolocated in QGIS. Interpretations of anomalies digitized atop the rasters. 

Example of anomalies suitable for the GPR:

• Grave shafts
• Building footprints
• Earthworks
• Utility pipes
• Geologic features

About the Instrument

We use a Bartington Grad601 magnetic gradiometer system with dual sensors. This mag system has selectable resolution of 0.01nT or 0.1nT, with exceptional temperature stability. The Grad601 also automatically adjusts to reduce power line noise with its 50/60 Hz rejection. 

Post-Processing

Data is downloaded to TerraSurveyor for data cleaning as necessary to improve data interpretability (such as spike removal, denoising, and de-striping) and grid combination. The data is then exported in a raster format to QGIS for geolocation and interpretation.

Example of anomalies suitable for the Magnetometer:

• Grave shafts
• Building footprints
• Disturbed earth
• Fire footprints
• Unexploded ordinance detection
• Pipe, cable, and drum locations

About the Instruments

We use Total Stations and RTK GNSS to provide precise locations for marking points of interest, boundaries, and more in a land survey.