Ground Penetrating Radar System – Does it Really Work?

Ground-penetrating radar or GPR is a highly advance form of technology that is used to give an output of the visual image of what’s under the ground. 

It works by sending multiple radar pulses or ultra-high frequency radio waves down into the ground and then reflected back out to the surface. 

These reflected signals are gathered by the GPR’s receiver and then analyzed to give an underground visual result of what has been scanned. The operation works exactly the same as the metal detectors.

Just like most metal detectors, GPR is very sensitive to the changes of the ground conditions. 

So in order to have better detecting result on these kinds of areas, constant movement of the equipment around the ground surface is required.

When it comes to usage, treasure or relic hunters are not really the majority of GPR users but many other industries such as utility service, structural analysis, law enforcement, geotechnical, environment and etc… 

Due to this reason, we can conclude that GPR do work.

How Accurate is the Ground Penetrating Radar?

The accuracy of a GPR equipment is dependent on the ground condition of the area that is being scanned. In general, there are two different types of ground conditions categorized as “conductive” and “non-conductive”. 

One good example of a highly conductive area are grounds with high content of iron or metal scraps. On sands, the area will be considered as conductive if there is a strong presence of salt water. 

On the other hand, non-conducive type of grounds simply means that the area is free from obstacles or interference which gives a highly accurate scanning result.

For those who are working in the construction industry, fresh concrete will be registered by the equipment as conductive. 

But through time, as it gets cured, it becomes non-conductive. If this happens, scanning it gives better accurate data.

To explain further how a highly conductive area affects the accuracy of a GPR, it actually slows down the radar signal from penetrating deeper into the ground. 

So the stronger is the concentration of the conductive material, the harder will the signal be able to pass-through it. 

There’s even more that you need to know and this is the moisture contents of the material which amplifies concentration of its conductivity.

So to answer the question above, the accuracy depends on the condition of the ground.

What can a GPR Detect under the Ground?

As already stated above, GPR is being used by many industries particular those that have something to do with buried or hidden object under the ground. 

But as a community of metal detector enthusiasts, we are more interested about hunting for those precious items.

Most GPR models are designed to detect large size objects that are even buried at an insane amount of depth. So for treasure hunters who are searching for large cache containing precious metals, GPR would be the perfect tool to be used. 

Unfortunately, for coin hunters or those who are looking for small objects, GPRs will have a hard time trying to recognize them.

Anyway, GPR can detect almost any kind of object buried under the ground because its process of determining objects is through its visual imaging display but requires careful analysis.

Is it Easy to Interpret the Data of a GPR?

Honestly, it is not easy to be able to interpret the data especially if you are just a beginner. 

Depending on the complexity features of the GPR model that you are using, it may take your several months to even years of practice or experience to master the art of being able to interpret the data correctly.

The acquired data is analyzed from the GPR’s display screen. You will be presented a digital visual image of the ground layers. 

Through a close observation and analysis of the shapes and colors, it should give you some hints. For better result, the data or images can be further processed into a computer for a more enhanced view and analyzation.

How much Depth can a Ground Penetrating Radar able to Reach?

The penetrating power of a GPR deep under the ground is indeed far superior to any metal detector around. 

However, there is no fix number or amount of depth due to the conditions of the ground. To make it short, the equipment will be able to perform better and reach deeper depth at a non-conductive ground area. 

On the other hand, high conductive ground area will prevent the signal from trying to reach deeper depths.

The size of the target object is also another factor when it comes to the penetrating depth of the equipment. 

This is because, the shape of a large object becomes clearly visible from the image data. But for small objects like coins, they are most likely mistaken as pebbles or small stones.

To give you at least some estimates, “on-air” tests shows an impressive performance of being able to reach the target for up to 1000 meters. 

Under sands or gravels, maximum depth is nearly 100 meters deep. And for the majority of other properties of the ground, the average range of depth is from 1 to 10 meters.

Issues with GPR Usage

There are some issues to GPR technologies particularly about its usage. It is not actually a user-friendly type of equipment. 

Thus, only those with considerable knowledge and expertise can effectively scan a certain area and able to interpret what has been detected.

Aside from the complexity of interpreting the image data, GPR equipment tends to consume too much energy. 

This is probably due to the powerful frequency signal that is being used. So if you are on the field with no access to an electrical power source, it can be a problem especially when you intend to cover a large area. 

You may have to come back the next or another day to complete the job.

For treasure hunters, there is no way for a GPR to be able to distinguish the scanned object about what type of material they are made-of. 

Thus, you can’t tell if the objects are gold or some kind of precious items.

Moreover, ground penetrating radar manufacturers are still on high competition trying their best to find solutions to those issues. 

One of their main goals is to achieve user-friendly features which I am starting to see on some of the new or latest GPR models.