Your Frequently Asked Questions about GPR

Your Frequently Asked Questions about GPR

Is GPR a safe testing technique?

Many people question whether there is any danger for the person using GPR equipment, and the answer is no. Although “ground penetrating radar” may sound like a hazardous technique, it is extremely safe and emits roughly 1% of the power of a cellular phone signal.

How does GPR equipment work?

GPR systems work by sending a tiny pulse of energy into a material via an antenna. An integrated computer records the strength and time required for the return of any reflected signals. Subsurface variations will create reflections that are picked up by the system and stored on digital media. These reflections are produced by a variety of material such as geological structure differences and man-made objects like pipes and wire.

Can I see non-metallic subsurface features with GPR?

GPR is extremely accurate when it comes to locating metallic and non-metallic objects. GPR systems work by sending a tiny pulse of energy into the ground from an antenna. An integrated computer records the strength and time required for the return of reflected signals. Any subsurface variations, metallic or non-metallic, will cause signals to bounce back. When this occurs, all detected items are revealed on the computer screen in real-time as the GPR equipment moves along. Users can even tell from the signal returned whether the feature in question is metallic or non-metallic.

How difficult is it to use GPR if I have never used it before?

Our students typically find that GPR is a much easier technology to learn than they may have believed.

GPR was pioneered by GSSI nearly four decades ago, and even though it began as a tool for scientists, vast improvements over the last three decades have been made to simplify and perfect this equipment so anyone in the utility locating, concrete scanning or road inspection lines of work can use our GPR products with ease.

GSSI provides training with its products and teaches a wide variety of classes to help the novice and experienced GPR user improve his or her skills. The classes typically include an introductory lecture and emphasizes hands-on practice with the equipment and software. This format ensures that each student walks away with a firm knowledge of the fundamentals of GPR and how to use the equipment in real-world situations.

How much training will I need in order to use GPR?

First-time users will need 2-3 days of training to become familiar with the equipment and ground penetrating radar theory. Training is provided free of charge with most GSSI equipment.

How deep can GPR “see” to locate targets?

Depth of GPR penetration depends on the material being surveyed and also upon the antenna frequency being used. For instance, GPR will penetrate ice, rock, soil and asphalt differently due to each material’s unique electrical properties. Lower frequency antennas will generally penetrate deeper, but there is a loss in resolution with the drop in frequency.

Soil conditions can vary greatly, which in turn affects GPR penetration. In general, dry sandy soils with little salt content return excellent survey resolution, but heavy clay-based soils are difficult to penetrate with GPR. In some situations, penetration depth may be limited to a few feet or less within clays, whereas pipes residing in sandy soils could be detected at depths up to 30 feet.

Your GSSI Application Specialist can help you find the equipment that is right for your project and profession.

Can GPR be utilized through water?

Yes. GPR can be utilized through fresh water, but it does not operate where salt water is present.

Can GPR be used through ice?

Yes. GPR works extremely well through ice and snow. They are some of the most favorable conditions for GPR.

Can GPR be used with GPS?

Yes. GSSI’s systems can integrate with most GPS systems. The GPS position data files and GPR scans are automatically matched within our systems so that the resulting data shows proper GPS position.

Can GPR be used to find gold?

While GPR is in use with many professional mining companies, the technology is not well suited to finding coins, gold nuggets or buried treasure. Metal detectors are more suitable. GSSI recommends checking with local, state and federal laws before beginning any treasure-hunting activities.

Can GPR be used to map cemeteries?

Yes. GPR is the best geophysical technique for forensic victim location and for the mapping of graves in cemeteries. While we can sometimes image the body directly, GPR responds well to the disturbances in the soil which are created when a pit is dug and refilled.

I saw something like this in the movie Jurassic Park and on TV shows like Crossing Jordan. Can GPR really show the skeleton?

No. That is a Hollywood adaptation of the technique. A grave will look like a large, upside-down “U” on the profile view and a rectangular shape in 3D planview.

Is GSSI equipment FCC certified?

Yes, for all GSSI equipment shipped and used within the United States. All GSSI GPR and EM equipment is certified by the United States Federal Communications Commission (FCC), and GSSI manufactures the only FCC certified air-launched horn antennas.

Is the equipment big and bulky?

Some of the lower frequency international antennas (i.e., 100 MHz shielded antenna) can be a bit large, but in general, GPR equipment is small enough to be handled by one person. Systems for two common applications, structural concrete scanning and underground utility locating, can easily be fit into the trunk of a compact car.

Can I use my cell phone around the equipment?

Since GPR operates by transmitting and receiving electromagnetic (EM) energy over a very wide frequency band, cellular phones, two-way radios and pagers should be turned off as they also transmit EM energy and may interfere with a survey.& If you must have them on, it is better to keep these devices at least 10-20 feet away from the antenna.

What is RADAN and what does it stand for?

RADAN is GSSI’s ground penetrating radar processing software. It has been developed over the last 20 years to aid in the processing and interpretation of GPR data. It will run on a regular laptop or desktop computer and provides the user with many powerful tools to clean up data and view data in 3D.& RADAN is an acronym that stands for RAdar Data ANalyzer.