TerraZond is the manufacturer of one of the most versatile, modular and diverse variants of Ground radio Imaging System, using variation in antenna array and signal generators design. Each variant of antenna modules below could be produced as air coupled and also as other media coupled (ground or water or any other media that customer wants). So, resolution per width will depend of media harmonization. All variants below are given for air coupled antennas.
There are 3 families of Imaging Units based on their version of Generators.
Further each family could have variants based on the Antenna Array Variation.
|Generator Versions||Model||Antenna Elements||No. of. channels||Spacing width in cm||Scanning width in cm|
|100 MHz to 1000 MHz||GRT-1x|
|500 MHz to 3000 MHz||GRT-3x|
|1000 MHz to 4500 MHz||GRT-8x|
Phased Antenna Array has 1channel; Narrow radiation diagram (15-20degress) and High Gain coefficient of antenna.
The peculiarity of the antenna module of the georadiotomograph excludes the presence of dead zones, unlike multichannel systems built on the basis of several monopulse georadars. The georadiotomograph uses one combined antenna for the entire frequency range (for example, the GRT-31 has a frequency range of 500 - 3000 MHz), which provides greater efficiency and productivity of work than a monopulse georadar, where the antenna characteristics are determined by the central frequency of the emitted signal. Thus, to work in a wider frequency range, monopulse georadars require several antenna options, which significantly increases the dimensions of the overall system and significantly increases the cost of a multi-channel solution, due to the need for separate UWB generator/recorder units for each pair of antennas.
The possibility of restoring a tomographic radio image, similar to a georadio tomograph, is not available for a standard monopulse georadar. Additional scans with a standard georadar for the accumulation of several parallel sections make it possible to construct pseudo-three-dimensional images that are sharply inferior in reliability and information content to the radio image of a georadiotomograph.
The Georadiotomograph Imaging Devices are consists of a UWB antenna unit of receiving and transmitting antennas operating in the frequency range from 0.15 to 0.9 GHz and from 0.7 to 2.6 GHz;
A sensitive high-speed synthetic aperture radar(SAR) generates linear frequency modulation (LFM) signals that ensures the operation of the georadar in the frequency ranges from 0.1 to 1.2 GHz and from 0.5 to 3 GHz at speeds up to 130 km/h (where the recording density of GPR tracks is every 10 cm); high-speed electronic relay; programmable logic integrated circuit (FPGA) for receiving, processing and storing geodata, as well as encoder and GNSS module.
The Georadiotomograph has advantage of having a modular cascade-expandable structure, with a varying width from 525 mm to 2325 mm (for the GRT-31 model), providing the operator with a three-dimensional data array, including from 7 to 31 radargrams every 7.5 cm in the width of the scan. The distance between the antennas can be selected for specific tasks, determining the resolution and capture width when scanning.
Due to the possibility of multichannel switching of antenna pairs, the georadiotomograph has the function of recording data using the common midpoint method (CMP) for mathematical calculation of the electrical properties of the upper contrast layer of the coating.