Highly cost-effective, non-disruptive and versatile, Ground Penetrating Radar (GPR) offers a prompt means of identifying underground objects. The advantages over a traditional, electromagnetic locator include GPR’s ability to see non-conductive materials such as plastic pipes and it accurately survey utilities buried up to eight metres deep.
Standard cable location tools may pick up ‘ghost readings’ caused by various environmental factors, such as high iron content, which may result in costly cable strikes. The GPR provides a comprehensive detection of obstacles underground, from Fibre Optic and HV cables to Streetlights, Drains and Culverts – meaning you can be safe in the knowledge that there will be zero utility strikes, ultimately saving you thousands.
How Does GPR Work?
Ground Penetrating Radar (GPR) locates underground objects by sending a signal into the ground, to then monitor the signal bounce back. Once the signal has been received, this is displayed on a screen for the operator to interpret, alternatively the data can be recorded for evaluation and processing later.
Instead of sending the signal through the air to look for objects, the GPR sends the signal into the ground to achieve the same objective. With traditional ‘CAT & Genny’ location tools, users are reliant on objects in the ground being metallic and having a detectable signal travelling along them. With GPR, as we are bouncing energy off objects, we are not restricted by the ability of the object to transmit a signal.
GPR has four basic components which combine to transmit a signal to bounce off objects.
Components of GPR
1. Transmit & receive unit
2. Control unit
3. Display unit
4. Power supply
The energy transmitted by GPR travels at different speeds through different substances in the ground. Radars measure the speed at which the signal returns and any changes in this speed are highlighted as some kind of change in the ground, these changes are represented as arches or ‘Hyperbolas’ on the GPR display. These ‘Hyperbolas’ deliver a 3D location of the targets we are looking for.
By using specialist software available with GPR, users can take the data and produce maps, depth slices and google earth images which can be geo-referenced with GPS. GPR has a very wide range of applications across many industries:
GPR has evolved over the past few years from a tool used by specialist companies and academics to a very user-friendly, effective and affordable resource for all.
In The field…
Our affiliate, Vp Equipment Specialists (ESS Safeforce, Brandon Hire Station, Groundforce, UK Forks and TPA), assisted a client on a pipeline project by providing an alternative method of ground surveying, making commercial savings and reducing downtime.
Employing standard cable location tools to survey the ground, the project was greatly delayed owing to various environmental factors. The high levels of iron content in the ground caused misleading ghost readings, which could potentially lead to workers inadvertently striking underground utilities such as high voltage (HV) cables at a potential cost of £10,000 and could be detrimental to a companies’ reputation, so an alternative solution was absolutely necessary. Following a HV cable near-miss review, a discussion with Vp plc took place to deliberate on alternative methods of ground surveying – ESS Safeforce stepped up to the challenge and introduced the GPR system as a potential solution.
ESS Safeforce provided the GPR system with an on-site familiarisation by our technical support, the company were then able to take the opportunity to train the relevant personnel for it to be successfully utilised on the pipeline. Three months into the project, the cost-effective GPR employment had effectively proven itself, avoiding ghost readings, detrimental obstacles and utility strikes.
Final words from the site manager:
‘The GPR is a great innovation and a proactive approach to preventing further damage that is giving site workers confidence on the job. It should’ve been rolled out years ago.’
Take your survey project to the next level; detect more and detect fast with our range of affordable Ground Penetrating Radar Systems, engineered to deliver a step change in capabilities with minimal change in work practices or training requirements.
To hire a GPR system, or for more information click here.