Validation and testing ground for ground penetrating radar systems
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Research duration: 2010 - 2021
Contact person: Azin Karinzadanzabi
To investigate small-scale features in the shallow subsurface, near-surface geophysics such as; Seismic, Electrical, Geodesy, Magnetic, and Electromagnetic methods are used. GPR[1] is an electromagnetic geophysical method that emits EM[2] waves to detect subsurface structures. Although the advent of GPR started in the field of geoscience, it is gradually utilized in civil engineering disciplines. GPR data quality depends on various software, hardware, and other factors. As a result, there is undesirable variability in measurement, processing, and interpretation. Radar technology developers have, to data, not expressed clearly what the operating conditions and potential of their GPRs are in the field of utility mapping. This has lead to ‘naive acquisition’ GPR equipment by construction firms. In other words, firms bought a potentially successful system that was either too complex to use, or were mislead by technology developers that presented only ideal and optimistic performance of their radar.
The main aim of the project is to develop a GPR validation method to find out under what condition it can successfully detect specific types of utility and what is the accuracy, reliability, and repeatability. If the results of this project is applied by certification institutes, this method, would in turn , create more transparency and clarify between the potential of GPR systems that are offered by distinctive manufacturers.
For this purpose, first, a geophysical test site needs to be designed and constructed in the University of Twente. This design should represent several typically Dutch underground infrastructure situations in terms of material, depth, and diameter. Various ground conditions such as; soil moisture content, soil types must also be taken into account, As these are the parameters that can affect the signal to noise ratio significantly and results in difficulties in radargram interpretation. The database that will be used in this project is consists of two types of data; the first one is the data that are acquired by conducting various tests on the facility test site. And the other is the data that are gathered from MAPXACT company. After data acquisition, the most critical step is signal processing to sharpen the desired signals and eliminate the noises. In the processing level, trace editing, amplitude corrections, noise attenuations, deconvolution, velocity analysis, and finally, GPR migrations will be applied due to the inherent characteristics of the dataset.
Based on the adequate surveys in various controlled and uncontrolled conditions, an exhaustive GPR application scenario will be presented. These scenarios will form the basis of the development of the validation method that will be developed in the final stage of the project.
[1] Ground Penetrating Radar
[2] Electromagnetic waves