Ground Penetrating Radar – An Overview
- BIMNYC Team
- 3 hours ago
- 2 min read
Hello everyone!
Welcome to the BIMNYC blog. In today’s post, we will discuss what Ground Penetrating Radar (GPR) is and its uses in the construction industry
GPR – What is it?
GPR or Ground Penetrating Radar is a geophysical method that uses electromagnetic waves to study the subsurface by sending a signal through the ground and measuring the reflected signal that bounces back. GPR works on the principle that different materials have different electrical properties of matter and with this, a GPR device is able to determine the depth and geometry of these subsurface reflectors.
Theory
As the waves are sent down through the surface and they hit a buried object or boundary with different electromagnetic properties, part of the wave energy is reflected back, while the rest continues to travel downwards. These waves travel at a velocity that is different depending on the electrical permittivity, and thus a signal passed between two different materials over the same distance will travel at different times. The time it takes for the wave to travel from the transmitter to the receiver is typically denoted as the “two-way travel time” measured in nanoseconds, for the time it will take to travel through the surface and reflect back through. Thus, the velocity of this wave can be calculated as such;
Where C is the speed of light in a vacuum, and εr is the dielectric constant. Depth can then be calculated with a distance formula such that;
Where t is the two-way travel time of the wave.
Applications
GPR is a useful survey method for areas that reality capture or similar technologies are unable to reach or scan. Typically, GPR systems are coupled with GPS capabilities to give accurate positioning data, which can be overlayed with satellite images or site plans. It has been used as an investigative aid tool for a multitude of different disciplines, such as:
Locating utilities
Detecting landmines
Determining water and ice depth
Mapping changes in rock type
Mapping soil changes
And more!
At BIMNYC, we are driven to use new and cutting-edge technology to meet our clients’ needs on any given assignment. Our goal is to share what we know and help you achieve your goals. If you are interested in collaborating with BIMNYC, give us a call at 212-433-3553 or send us an email at info@bimnyc.com
Thanks,
BIMNYC Team