What Is the Best GPR Scanner?

Man Pushing Ground Penetrating Radar Equipment

A Detailed Explanation of the Ground-Penetrating Radar System Used by Sentry Mapping

What is the best Ground-Penetrating Radar (GPR) system? There are many to choose from, and it’s a tough question because there are so many factors that go into making a decision. We have found that the Geophysical Survey Systems International (GSSI) SIR 4000 system gives us the best results for our clients. 

It has an effective range of up to 200 meters in one scan, and allows in-field data interpretation with a high-resolution viewing screen, which saves time for both the technician and the client. 

This scanner also has many features that make it stand out from other competitors on the market such as high-frequency radio waves, which allow for deeper penetration; increased sensitivity, which means more accurate data capture; automatic gain control, which prevents overloading due to ground conditions; and an integrated antenna with a powerful magnet mount.


Compatible with GSSI antennas


32 GB of space


4.5 KG (10 lbs)




SIR 4000 harness, SIR 4000 stand
The SIR 4000 is typically used for:
Utility designation
Concrete inspection
Mining and geology
Environmental assessment


SIR 4000 Control Unit
Lithium-ion batteries (2)
Dual-bay battery charger
Transit case
User Manual
2-year warranty

photo of man pushing GPR Scanning equipment

How does our GPR System Work?

GPR is a geophysical method of non-destructive testing (NDT)that uses electromagnetic waves to identify targets below the surface of the ground, such as underground utilities and other man-made subsurface structures. The data collected is then used to create a profile of what lies below the surface or in other words an underground view. 

Ground Penetrating Radar sends tiny bursts of energy waves, from 1 to 1000MHz. These pulses transmit signals into the ground. The system then records how long it takes for the reflected signals to bounce back using various sensors such as antennas or metal detectors. 

Each burst of higher-frequency pulse identifies if there are any hidden objects beneath the surface which helps determine their location. The GPR data can be used for various applications such as archaeology; defense industries identify landmines; mining companies detect ore veins buried under deep layers of soil etc.

GPR equipment is an essential tool for a wide variety of industries. From oil and gas to geotechnical and utility locating, these instruments collect data on underground structures by emitting electromagnetic energy into the ground and then measuring how they bounce back at different frequencies. 

GPR Surveys can:

Locate and mark buried utilities
Conduct concrete scanning at a construction job site
Locate unmarked graves
Identify underground pipes, lines, and cables
Discover buried vats, tanks, and tombs
And much more

We Offer Real-Time Data Analysis With GSSI SIR 4000

The best GPR systems on the market today offer real-time data analysis that helps technicians understand what their results mean. In one or two scans, we can get a complete profile of all objects in an area from utility lines to manholes and everything else. The best part is you don’t have to wait for days while your team waits for the results. 

We can set up and scan an area in a matter of hours, which is almost impossible with other GPR systems available right now. Once the data has been collected by our best GPR scanner we collect it into software that allows us to see what’s under the ground exactly where you want them to be located on your map.

We can mark and label anything we see in the ground so you know exactly where those markings are located. This GPR scanner gives us quick, clear information that allows our team to provide clients with survey-grade maps showing everything under their property without any guesswork or missed data.

What are the GSSI SIR 400’s Limitations?

Our ground-penetrating radar systems can reach 15 m into sandy soil or solid materials like granite and limestone. When the substrate has high electrical conductivity, it dissipates electromagnetic energy more quickly resulting in a signal loss at depth because all of that energy becomes heat instead. In substrates with clay soils, water, and salt – penetration depth may be as thin as a few centimeters.

Beyond the limitations that can be experienced with this system mentioned above, technicians will have to deal with a steep learning curve before they can produce quality results. Our team of highly trained professionals has years of experience working with the GSSI SIR 4000 to provide clients with the most accurate results. We have successfully completed hundreds of projects with this system and have produced quality results time after time.

photo of hilly graveyard with tomb stones

How GPR is used to Locate Buried Utilities

Utility lines are buried to protect them from accidents and natural disasters. However, as years pass they can become covered with dirt or debris that make it difficult for the utility company to find the line when repairs are needed. 

This is where GPR comes in handy! GPR allows engineers to locate utilities under long distances of surface without digging up yards, sidewalks, and streets. Our system works by emitting radio waves at frequencies typically between 30 MHz (megahertz) and 300 GHz (gigahertz). 

These waves bounce off objects in their path like walls, pavement, pipes, etc., collecting data about what’s beneath the ground. Data collected can be used to create images of underground construction which helps pinpoint where utilities are located, preventing costly errors, injury, or even death.

Are Sentry Mapping and out GSSI SIR 4000 the Right Choice for Your Project?

Our engineers use a combination of best practices in GPR, high-resolution imaging, and complex data analysis with superior technology for excellent project results. We are able to provide our clients with accurate information and the best possible solution every time thanks to years of experience working on projects just like yours!

Our team has successfully completed hundreds of successful projects using this system that gives us the best results time after time. We have been using the GSSI SIR 4000 system for many years and we have found it to be the best in terms of range, efficiency, and viewing screen resolution when compared against other systems on the market. We use our GSSI SIR 4000 for cemetery mapping services, making cemetery burial plot maps, locating underground utilities, and much more!

If you are looking for an experienced company that will provide you with a detailed explanation of our ground-penetrating radar system and how we use it, then give Sentry Mapping a call! Our team of experts is standing by to answer any questions you may have regarding our products and services. Reach out today to learn more about how we can help you!