A comparative study of Single Channel and Hand-Pushed Array Ground Penetrating Radar (GPR) Systems for Utility detection

Summary

This comparative study evaluates the performance of single-channel GPR (Ground Penetrating Radar) systems versus hand-pushed high-density GPR arrays for utility detection. The research in Gainsborough, UK, highlights key differences in data quality, acquisition efficiency, and processing time.

Key outcomes:

GPR arrays significantly reduce acquisition time (by two-thirds) and provide higher resolution data.
Single-channel GPRs are more cost-effective for small projects.
For mid- to large-scale commercial utility surveys, GPR arrays offer a better long-term return on investment due to improved data quality and operational efficiency.

OBJECTIVE

To investigate and compare the effectiveness of two GPR solutions for utility detection:

Traditional single- and dual-channel GPR
Modern high-density GPR arrays

The goal was to evaluate performance across parameters such as:

Data resolution and density
Field acquisition time
Processing and interpretation effort
Cost-benefit implications

PROJECT

A side-by-side field comparison was conducted using a MALÅ Easy Locator Core and a MALÅ MIRA Compact:

Both systems were used at the same site, and data were processed using identical procedures and software (MALÅ Vision Desktop), ensuring a controlled and fair comparison.

FIELD WORK

GPR Array:
- Continuous coverage in one direction
- 6.5 cm channel spacing
Single-channel GPR:
- Bi-directional grid
- 0.5 m spacing between profiles
Both systems collected data at the same intersection, ensuring consistency.

SITE DESCRIPTION

Location: Gainsborough, Lincolnshire, UK
Site characteristics: An industrial area with a dense network of known underground utilities is ideal for testing visibility and performance in realistic conditions.
Pre-survey work: Included reviewing maps and utility drawings, site inspection, and GNSS positioning.

Fly-through of MIRA Compact data from Gainsborough, using MALÅ Vision Desktop.

Stats and Conclusions

Single-channel GPR:

Bi-directional measurements

Profile distance: 0.5 m

Point interval: 0.025 m

Data size: 737 Mb

Data density (10m²): 3.2 million

Acquisition time: 6.5 hours*

Processing time: 15 min

GPR array:

Single direction measurements

Data channel dist.: 0.065 m

Point interval: 0.05 m

Data size: 1120 Mb

Data density (10m²): 12.2 million

Acquisition time: 2.5 hours*

Processing time: 15 min

*Data Collection Efficiency: Both data collections were collected with a hand-pushed cart at normal walking speed. The time of data collection for the array was 2.5 hours, and the single channel collection was 6.5 hours. The significant difference is due to the need to collect in 2 directions with the single-channel GPR and only in 1 direction for the array.

Comparing single channel GPR data with high resolution Array data at roughly 1 meters depth (Gainsborough).

Conclusion

While both technologies are viable, the GPR array offers clear advantages in data quality, processing speed, and usability. For commercial applications, especially larger sites, the array system is the more efficient and cost-effective solution over time.

Acknowledgement

We would like to thank the guys at Sygma who assisted in the data collection.