FAQ. what you should know

What is GPR?

Ground penetrating radar is a special geophysical device used for underground exploration through reflected electromagnetic waves. The electromagnetic pulses are transmitted to the ground by transmitter through antenna. A receiver through the second antenna receives the electromagnetic waves which are reflected by anomalies underground. The reflected wave signal is recorded at each point of measurement. During movement of a GPR there is generated an image of underground structures, layers and various anomalies.

Are there any disadvantages, limits of GPR?

For someone it should be a surprise that they do not find out exactly from which material underground anomalie discovered by GPR is composed of. Therefore it is important to explain that the electromagnetic wave is reflected only when it encounters interface with a different material – different conductivity or permitivity. This is a comparative measurement. This means that we get information about a change of material or its structure and not directly about its type. Limits of a depth range exploration are greatly influenced by transmitter power and attenuation of electromagnetic waves in the rock. Please see the question How it is possible that Roteg can see deeper than conventional GPRs?

What are the advantages of GPR? What other devices can not?

The advantages of GPR measurements and exploration are evident. Among the most significant is saving time and money (measurement is very fast in comparison to other geophysical exploration methods). The device is simply to use. It is usually operated by 1-2 persons. Required is only minimal measurement preparation. Using the device does not affect the environment, interference in the soil by excavation or drilling is minimized.
Compared to many other devices, GPR is very special in its ability of simultaneous measurement of three key values: time, intensity and phase of the reflected wave.
In contrary to other geophysical methods like electroresistive method, VLF, DEMP… GPR has a much better resolution.

Why to choose the Roteg?

  • Unique and state-of-the-art device for a wide range of antenna frequencies
  • Cooperate with other types of transmitters
  • Airwave transmitter synchronization
  • Several times greater depth range than the most of the competition GPRs

This brand new GPR, compared to the existing GPRs, is characterized by much higher pulse power, higher antenna voltage (5-10 kV) and in particular the special design of the pulse generator using spark gap transmitter technology which bypasses commonly used semiconductor components MOS and LDMOS. Spark gap transmitter produces Dirac pulses of lengths up to 3 ns by directly discharging capacitors.

How it is possible that Roteg can see deeper than conventional GPRs?

In the first place the depth range underground exploration is influenced mostly by the transmitter performance and by selected antenna frequency. The receiver must be able to process and save these strong signals. If the receiver is able to process multiple reflected signals in one point of measurement, it is possible to suppress various interferences and achieve a better resolution and greater depth range.
Roteg is unique in its ability to record very strong signals from the transmitter. It has a large dynamic range for signal processing and it has a capability to capture details from small and great depths. Concerning the transmitter power, common GPRs transmit pulses with a voltage around hundreds of volts, our Roteg transmitter have pulses e.g. 5­-10 kV.

Does it really works?

Yes. We have our results verified by measurements in areas with the known structure of underground. Please check out our radargrams or references. We are also ready to make a comparative measurement with any of your device.

If I am interested in shallow exploration, should I choose a different GPR?

Roteg performance allows you to achieve the greater depths, but its benefits are proven also at shallower survey. Its advantages shows especially in clay, heavily mineralized and wet soils where the other georadars have problems to reach even a small depth. Contact us and we will be pleased to advise you.

Do I have to be an expert?

No. Not either for choosing GPR nor for measurement itself. We can advise you how to choose the best device. Data collection is very easy. Any time during the measurement you can see displayed strong underground interfaces. Next step is data processing on PC and there you get more powerful tools for detailed display of radargram. To use advanced filtration techniques is much more challenging however these techniques are thoroughly described in the literature and on the internet.

What do I need to know to choose the right device?

At first, it is necessary to make clear in advance how large underground anomalies you want to find, how deep and in which kind of rock. Our device is multi-purpose but the most important is to choose the right type of antennas.

What is the main application of GPR Roteg?

GPR Roteg is widely used to find and locate utilities, cavities, waterlogged ground, the level of bedrock and it has exceptional capability to measure geological profiles up to depth of hundreds of meters.

It is especially suitable for:

  • Surface and in-depth underground exploration
  • Monitoring and locating of buried objects
  • Measurements in the tunnels and overground buildings
  • Site investigation before the start of construction activities: locating cavities, backfilled cellars, wells, old building foundations, determining of safe paths for horizontal drilling and boring…
  • Underground utilities location: cables, metal, plastic, ceramic and concrete pipelines
  • Archaeological, criminalistic, pyrotechnic survey: hidden objects, tunnels underneath of the national borders, search for old ammunition, deep set aerial bombs…
  • Localisation of cavities, caves in the karst areas
  • Detection of the individual layers in the soil, bedrock, geological faults…

What can be seen in radargram?

Radargram represents a vertical cut in soil. Final profiles provide an exceptional image of distribution of geological objects in the soil. Radargram provides informations about mutual relations of found anomalies (above and below deposited objects…). You can very clearly see all interfaces of underground materials with different conductivity and permittivity. The more these materials differ from each other in terms of these properties, the more contrast is their interface. On the left side of radargram is scale in nanoseconds, the recalculated scale for depth in meters is on the right side of radargram. For more information, please check out the article How to understand radargrams.

What are Roteg operation costs?

Minimal. Only general maintenance of the exterior parts of device is needed, batteries are rechargeable.

If I do not plan to buy a Roteg yet, may I order just measurement or survey service?

Currently we do not offer a measurement service. Of course, everything is matter of individual agreement. Please contact us, we can eventually recommend you someone else.

When I buy a Roteg, will you provide me some sort of training?

It is possible to arrange training. For more information, see the question Do I have to be an expert?

What is the price of Roteg?

The PC and GPR receiver are included in the base price. Transmitter and antennas are optional equipment according to your requirements, so the final price very much depends on selected equipment and accessories. For more information or to request a catalogue, please contact us.