GPR or Ground
penetrating radar is a device that allows
you to “see” underneath the surface using pulses or electromagnetic waves
through the antenna. No matter how modern the equipment is, it’s not going to
supplant the law of physics. So there will always be constraints depending on
the condition on the ground. A monitoring screen is also present so the
operator can study the results which are delivered in a matter of nanoseconds.
How deep can
it see?
The problem is that the GPR can’t probe far through the rocks,
soils or concrete. How does that happen? It’s called signal interference. The
efficacy of radio waves will decline when they hit energy absorbing materials
until they become undetectable. Try picturing out talking to a cell phone and
entering a tunnel and the signal dies out. The concept is similar.
Lowering
frequency
If you lower the frequency of the ground
penetrating radar, you improve your chance of being able to see deeper. But there’s
a drawback to this method. As you dial down the frequency, the resolution
suffers. Second, the radio pulses diffuse instead of traveling as waves and you
would be better off using the eddy current measurement machine which is another
non-invasive way to probe the subsurface.
