Clever geo-radar ‘opens eyes’
A road is a convenient place to hide any traces of negligence. After the asphalt is laid, it’s a challenge to define the quality of the materials or work.
By Dmitry Patolichev
Unsurprisingly, after scientists used their new geo-radar, which enabled them to look beneath the surface of a road section under repair and then showed the results to the foreman, the latter proclaimed, “Guys, we do not need you here!” Such a response was expected, as the smart device precisely measures the uniform thickness of the road, and of the layers of sand and gravel. Gravel amounts can also be well determined. Of course, such irrefutable facts could leave workers without a bonus, or create more serious problems for them. With this in view, it’s no wonder that workers welcome the radar devices with caution.
“Subsurface radars — which operate in the microwave spectrum (like our device) — are produced by many countries and are widely used to control quality in construction, industrial production, customs affairs, geology and archaeology,” explains Yelena Maximovich, a candidate of technical sciences and a leading research officer at the radio-tomography laboratory of the Belarusian National Academy of Sciences’ Applied Physics Institute. “This theme is topical and, unsurprisingly, has been realised as part of a state programme focused on scientific studies. Much attention was paid to the development of sensor parts and signal processing. Using a grant from the Belarusian Republican Foundation of Fundamental Research, we’ve joined our colleagues from the Russian Academy of Sciences’ Institute for Physics of Microstructures to solve the problems dealing with detection of an object and restoration of its form. Most globally sold radars are impulse — making it possible to easily lose signal passing from one antenna to another (which reduces noise). However, we use a wide range variable frequency which enables us to ensure a higher depth resolution, paying no attention to antenna characteristics.”
The accumulated experience has proven its advantages already: our scientists have won a tender to detect and identify antipersonnel metal-free mines (via the International Scientific-Technical Centre). Such mines are truly dangerous, as they cannot be detected by modern mine detectors. Moreover, these standard detectors often produce a vague picture, making it difficult to identify objects on a monitor. Also, it is only experienced operators who reliably define the objects they are seeing.
To avoid sweeping statements, Ms. Maximovich demonstrates the results of field tests. “Look here,” she points at the monitor. “Here we can see not only the mines, but also stones and cans filled with wet sand (added as masking). Can you distinguish a mine?” I easily found it and, no doubt, such a task is even simpler for an operator-specialist.
Importantly, the radar makes it possible to move at a walking speed. Its micro-processors promptly display the subsurface structure. Of course, mine detection is vital, especially in areas where fighting has occurred recently. The USA and Europe annually host international conferences for scientists to share their most advanced signal processing methods and devices. The International Scientific-Technical Centre accumulates serious projects of post-Soviet scientists. However, if the Belarusian military does not show interest in this experience, then the scientists do not insist. After all, the army has more relevant tasks.
Devices of the kind make it possible also find underground cables and metal and plastic pipes. Sometimes these pipes are detected in places and depths which differ from official plans. As a result, excavators and horizontal directional drilling tools often hit these, causing their failure. Similar problems arise in the walls of old buildings.
Since a geo-radar detects both the depth and location of a pipeline, its use would help avoid many expensive problems. Specialists of Minsk’s City Executive Committee understand this and are very interested in the development. “A microwave radar, or microwave tomograph, is a universal tool, especially regarding biological tissues” notes Ms. Maximovich. “We’ve conducted tests on models which showed that our methods make it possible to detect muscle and fat tissues. Moreover, differences between these tissues are easily seen. Accordingly, we have no doubt that the correct application of these methods could detect contrasting tissues, for example, mammary tumours. Twenty year of development and experience of foreign specialists confirm this well. They believe that microwave radars could become a complementary tool, alongside x-rays and ultrasonography, to diagnose tumours. We believe that, one day, all these developments will be widely used.”