BASIC FEATURES OF GEORADARS GROT AND SOME RESULTS OF USING THE GEORADARS GROT-10 AND GROT-11 FOR A STUDY IN GEOLOGY AND THE NATURAL GAS INDUSTRY

In the georadars GROT with the increased power the precision gas discharger is used for the formation of sounding pulses with the amplitude of 5KV. On the gas discharger an increase in the voltage even up to 15KV does not create problem. In the georadars GROT the method of comparison is used instead of the method of gating the signal. For registering the signal the high speed comparator is used which compares received signal with a certain assigned threshold and the fixes for one sounding pulse all moments of threshold exceeding by a signal in entire range of the recorded time delays. Complete wave signal is recorded for 128 pulses with a sequential change in the threshold. Threshold value changes according to the quasilogarithmic law that makes it possible to display on the screen of liquid-crystal indicator the complete wave signal with the dynamic range of 100dB (7-bit DAC gives 42dB and controlled attenuator - 56dB). In the binary forms mode the possibility of registration and memorization simultaneously of sequence with the zero threshold and additionally two frames with any thresholds from -16 to +16 is provided. In the georadars of a GROT series the resist-loaded dipole antennas with the optimum damping factor for the suppression of the antenna ringing are used. If necessary, the mode of averaging on 16 measurements is included for an increasing the sensitivity. The real potential of the georadar evaluated according to the experimental data, composes 110-120dB (theoretically calculated potential exceeds 160 dB). Georadar GROT-10 (the medium frequency of 100MHz) is capable to sound soil at depth 6-10m on the heavy soils and up to 50m on the light dry soils. Sounding depth of the georadar GROT-11 (the medium frequency of 10MHz) is ~50m on the heavy soils and ~200m on the light soils. Georadars GROT-10, GROT-11 are protected by patent in Russian Federation; there is a claim PCHT/RU 03/00150. We already carried out more than 400 different search works with georadars GROT. Algorithms and programs for data processing of georadar sounding are developed. For more details look at http://www.zaotimer.ru/eng/