How Ground Penetrating Radar Works

What is Ground Penetrating Radar?

Ground Penetration Radar (GPR) is a geophysical method of identifying what lies beneath the ground, typically using radio waves in the microwave band. GPRS uses this technology for private commercial applications such as utility locating, concrete imaging, and other services. The ability to find out what’s underneath the surface without breaking the ground is vital because it will provide critical subsurface infrastructure information in a non-invasive way. But ground penetrating radar went through multiple iterations before it became the staple to subsurface damage prevention that it is today.


The first patent for radar itself was issued in 1910 by Gotthelf Leimbach and Heinrich Löwy for a continuous-wave radar for detecting buried objects, six years after the first patent for radar itself. Dr. Hülsenbeck improved the depth resolution of the radar in the future by using pulses instead of continuous waves. W. Stern used ground penetrating radar for the first time in 1929 to measure a glaciers’ depth.

During the 1970s, military applications led to the expansion of research in this field. However, the first affordable consumer electronic equipment was not available to the public until 1975. In the following years, commercial applications began to appear. As part of the Apollo 17 mission, an airborne radar called ALSE (Apollo Lunar Sounder Experiment) was sent into lunar orbit in 1972. It was able to take depth measurements of up to 1.3 km even though a suitable storage system was not available at the time.

Since its introduction, there has been an extensive range of public and private applications of ground penetrating radar.

How Ground Penetrating Radar Works

Ground Penetrating Radar (GPR) is at the center of GPRS’s operations and aids in utility location, leak detection, and many other functions.

There are generally three main components of the Ground Penetrating Radar or GPR. These include the control unit, the transmitter, and the receiver. 

There are many different forms in which GPR equipment is available, but its function remains the same regardless of the form factor. The antenna works by emitting electromagnetic waves of a specific frequency into the ground through a transmitter. At this point, those microwaves are reflected up to the antenna receiver at different travel times and different signal intensities (or amplitudes). A visual display is then generated for the operator by encoding and sending this information to the control unit, where it causes a display in the form of an image. 

The electrical conductivity of the earth or concrete being scanned, the frequencies being transmitted, and the radiated power contribute to the effective range of ground penetrating radar. The more conductive the ground scanned is, the more challenging it is for electromagnetic waves to penetrate it. This is because the electromagnetic wave is attenuated. Due to these factors, there are often compromises on either depth or the resolution of the image generated by the electromagnetic waves. Higher frequencies provide a higher resolution but cannot penetrate the ground as far as lower frequencies and vice versa. For example, scanning ice may produce precise GPR results up to kilometers deep; dry sand or concrete may have an image of up to 50 ft, but wet materials like clay soils may only allow centimeters of penetration. In most use cases, GPR is used to render images of the ground between five to ten feet deep.

The most challenging aspect of ground penetrating radar is that it requires highly trained experts to use the equipment. The reason for this is that the data collected creates layers or hyperbola which must be interpreted by an expert. Trained experts can distinguish the difference between the subsurface objects or obstructions. GPRS ensures that our project managers are highly trained and SIM certified. SIM stands for Subsurface Investigation Methodology. It’s an industry standard that ensures everyone is scanning for subsurface damage prevention at an adequate level. SIM requires that all our Project Managers be equipment experts. The SIM standard specifies that a professional locating contractor must utilize multiple locating technologies. SIM Specification also details much more than standard training requirements. To be SIM certified, an operator must complete a minimum of 8 weeks of field mentoring and two weeks of classroom training. And third, SIM requires our Project Manager to be proficient in the best methodologies.

Why use Ground Penetrating Radar?

Ground Penetrating Radar is a powerful tool with a multitude of applications. It’s commonly used in the following fields:

  • Criminology
  • Archeology
  • Military
  • Utility
  • Construction
  • Geology
  • Law Enforcement
  • Forensic Science
  • Education and Research
  • Mining
  • Exploration

These are just some of the applications in which ground penetrating radar is used. One famous example of how GPR was used in forensic investigation was in the search for Jimmy Hoffa. The notorious mob-tied leader was convicted of several crimes without successful imprisonment and then disappeared in 1975. It is supposed that Hoffa was captured and eventually buried by the mafia. GPRS was called upon to investigate the suspected area of where his body may reside. GPRS believes they have found the body’s location, but as of early 2022, there have not yet been any excavation attempts.

GPRS is one of the largest private utility scanning companies. GPRS has completed more than 250,000 projects with over a 99% accuracy rate. Scanning before digging, trenching, cutting, or coring is vital to project success. This noninvasive method decreases costs and increases safety for employees.

Every year there are thousands of accidental utility strikes. These strikes can result in costly delays, repairs, injuries, and even fatalities.

That’s why GPRS is committed to 100% subsurface damage prevention. 100% subsurface damage prevention means that no more projects will be stopped due to accidental utility strikes. That is why safety is one of the five core principles that guide our company. We want to partner with others to create a future completely free of subsurface damage.

Schedule a Project Today

GPRS specializes in all types of ground penetrating radar services. Our Project Managers have the equipment and expertise to handle all subsurface challenges presented. GPRS does this by utilizing various equipment paired with their industry-leading SIM process.

So don’t wait. Click here to schedule a project with GPRS and allow our highly trained Project Managers to keep your projects on time, on budget, and safe.