GPR for IEDs
Custom low impact transport outfitted with five Noggin 500 GPR units traversing a road in Iritrea.
Overview
Regional warfare create hazards on road in Eritrea from buried IEDs and landmines. A GPR system was configured to allow regular monitoring of a main thorughfare. Regular profiling allowed the field team to identify suspect zones and identify areas of new distrubance possibly assocaited with burial of new devices under the road between traverses.
Problem
IEDs and landmines buried in and beside roads present a major hazard. Historical buried items may still be present and, if on-going warfare is occuring, new devices may be emplaced at any time. There are numerous issues but two primary challenges are first how can one reliably detect such devices and second, how to ensure no is killed or injured in the process. While traditional metal detectors can help, many new devices have minimal or no metal creating a huge challenge.
GPR Contribution to Solution
GPR provides the unique capability to see into the subsurface and to detect all manner of changes. GPR can see both metallic and non-metallic objects. Further, GPR can even sense soil disturbances themselves. While GPR has many attractions it is a challenging technology to deploy effectively and some soils are opaque to GPR signals.
A major challenge with using GPR is that it can sense explosive devices as well as other benign targets. To a GPR sensor, a rock can look very similar to an improvised bomb made from fertilizer and diesel fuel! Defining a locating process leads to assigning measures of probability of detection and the false alarm rate. How does one maximize one and minimize the other?
This example from a real program in Eritrea saw a multi-channel GPR array installed on a custom low impact footprint vehcile designed for IED mapping. Five Noggin 500 MHz GPR units were boom mounted on the front of the vehicle enabling a full vehicle width to survey as the vehicle drove along.
The data were viewed in real time to identify immediate anomolous zones and recorded to provide a map history for comparison with repeat surveys. Having accurate positioning along with the GPR data is essential.
Regular and repeated GPR surveys mitigate risk. Having a background record makes it much easier to identify where changes have occured. Systematic comparison greatly increases the probability of detection and reduces the false alarm rate.
An example illustration of map image at a fixed depth below the surface showing anomalous responses over buried mines.
The system shown here has been used in several locations in Africa. The approach has been highly effective and has no doubt saved many lives in the bargain.
We acknowledge the helpful insight, data and photographic information provided by Stefan Schultheiss.
Results & Benefits
The multi-channel Noggin array system approach used in this study demonstrates the value of GPR for IED and landmine detection. Some key benefits are:
- GPR systems are compact, portable and rugged
- Operation is simple and intuitive and tailored to the user need
- Noggin systems can be readily integrated with accurate positioning systems such as GPS
- Users can be effective with only a few hours of training
- Systematic search protocols are available as best practice guides
- Locate and mark operation provides immediate risk zone identication
- Repeated mapping improves probability of detection and reduce false alarms
GPR responses vary greatly depending on the target being sought and the host material. GPR response variability can be challenging to new GPR users. When learning about GPR, the best practice is to review several similar case studies to develop an understanding of variability. Check for other insightful information on the resources tab to learn more. Use Contact Us or Ask-the-Expert to reach our Application Specialists who can help you tap into Sensors & Software's vast array of technical information.