On the Road: Geophysical Survey using GPR

May 5, 2020, 7:00 am

For many at GSSI, life before the “stay-at-home” initiative was filled with face-to-face events including equipment demonstrations, trade shows, and trainings. On a chilly January morning, Ken Corcoran, Product Marketing Manager, packed up one of GSSI’s new customized vans from our Nashua, NH headquarters and headed down to Haddam, CT to assist in an equipment demonstration with our two Geophysical Application Specialists, Brett Caldwell and Amber Onufer. Working with geologists from the United States Geological Survey (USGS) from the Connecticut office, the team chose a location just off the Connecticut River. The geologists hoped that the increased depth penetration and superior resolution of the new GS Series antenna could image the deeper geological features. The team also brought several types of GPR systems including; UtilityScan, StructureScan Mini LT, StructureScan Mini XT with Palm XT antenna, SIR 30 and SIR 4000 controllers, and multiple antennas to showcase the range of GSSI’s suite of products.

The day was spent highlighting the capabilities of the 200 HS antenna to field geologists from the New England Region. While it was extremely cold and windy, they toughed it out by taking breaks in the van with coffee and donuts, reminiscing about years of using GSSI GPR equipment in the field.

GSSI survey equipment

Above is a picture of the equipment that was available for use during the demonstration. Equipment shown right to left: 2 GHz Horn Antenna, StructureScan Mini XT, Palm XT, StructureScan Mini LT, 900 MHz antenna, UtilityScan Pro, UtilityScan, SIR 30, SIR 4000, 350 HS antenna, 200 MHz antenna, 200 HS digital antenna and 100 MHz antenna.

GS Series at a Glance

The GS Series is our newest high-performance GPR system designed for applications that require deeper depth penetration. The system consists of several components: the HS Module, which is the communication bridge from the antenna to the controller; a digital wireless 200 MHz antenna (200 HS); and a controller, which may be either a SIR 4000 (with an optional WiFi module) or a Panasonic G1 Tablet. This 200 HS antenna is a new antenna design and uses GSSI’s patented HyperStacking® technology, which improves signal-to-noise performance and increases the antenna depth penetration under ideal soil conditions. A new WiFi module allows users the ability to use their existing SIR 4000 controller to operate the new antenna. The 200 HS also improves survey efficiency and in-field use. The WiFi range can reach distances of up to 15 meters (50 feet) within line of sight between the controller and antenna.

GSSI 200 HS Antenna

Picture above is the 200 HS with the external survey wheel and optional external GPS.

Field Results

The GSSI team had a productive day collecting transects across a nicely manicured field within a park. Ken Corcoran said, “What a great spot to collect GPR data. Clearly the USGS Geologists from Connecticut know their region well. The GPR data we collected showed the stream terrace deposits that were overlain by modern alluvium in the area. We are fortunate that here in New England we have soils that allow us to see deeper and image these types of subsurface features.” Below is a sample of data that was collected on site and analyzed with the geologists.

Sample data set collected during field trials. High amplitude lenses at center of time range shows a nicely characterized stream terrace deposit. System used – the GS Series 200 HS antenna with G1 tablet.

As we look towards the future, our team of Applications Specialists and Technical Trainers cannot wait to get back into the field. We’re excited to connect with the GPR community once again and look forward to hearing stories from the field.

Credits// Author: GSSI

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