N. N. Tokarev - Ph.D. (Eng.)

Simulation of signals from a walking intruder generated by radio-wave detectors (RWD) with buried antennas is actual to estimate received characteristics in case of changes of ground s state (dry-moistened - wet) and its electrical parameters. Approximate formulae based on assumptions true within certain frequency bands, distances and environment parameters are used for engineering analyses of fields and signals generated by buried antennas. The report uses previously analyzed approximation for engineering simulation of electromagnetic (EM) field propagation close to the ground surface and low frequency approximation for simulation of EM field diffraction process on cylinder model of a target-intruder. On basis of these approximations, it suggests a signal simulation of a walking intruder in RWD with buried antennas within operating frequency range below 100 MHz, which is really used in these RWD. Using the suggested simulation, form of intruder signal and spectral characteristics of signals, changes in signal amplitude depending on the point where an intruder crosses the boundary, on the ground conditions, on typical dimensions of an intruder, are calculated and analyzed. Suggested earlier method to decrease RWD detection zone width by averaging out signals in operating frequency wideband and leveling lateral oscillations of signal, which corresponds to highest Fresnel zones, is given. Simulated and experimental results are compared and show satisfactory correspondence.