SPIDAR® systems network any number of Noggin and pulseEKKO PRO GPR systems together into a single data collection platform and provide maximum flexibility for data collection. While the possibilities are endless, a common deployment is several systems with the same frequency spaced apart laterally to provide a swath of data in a single pass. This allows large areas to be surveyed in a fraction of the time compared to a single system. In this case study, a client needed to map soil variations over a 7.5 hectare (19 acre) field to optimize crop selection.

To achieve this, a SPIDAR® system with four Noggin 250’s spaced 1.5 meters apart was constructed from PVC pipe and 4 plastic sleds. The platform was 4.5 meters (15 feet) wide, had an integrated odometer wheel and GPS for positioning, and was towed across the field using an ATV “Mule.” With SPIDAR®, the survey parameters for each system (time window [depth], step size, and stacks) can be different.

In this case the survey parameters were identical for each system:

Time Window = 50 ns (Depth = 2 m)

Step Size = 0.05 m

Stacks = DynaQ

The offsets between systems are entered into the SPIDAR® data acquisition software so that the relative position of each system is known for the entire survey. A total of 66 line kilometers of data with 1.32 million traces and 165 million data points was collected in about 4 hours. The depth slice at 17 ns (approximately 0.60 m deep) shows a distinctive 1 hectare area in the North East corner of the image with consistent high amplitude GPR responses. This response is characteristic of a change in soil properties (texture, structure, moisture) in that area. Based on these results, the anomalous area was cored to analyze the soil composition in detail.