Antenna array with distributed receiving and transmitting high frequency (HF) antennas used to scan structure environment; this array helps sounding environment from different angles. For detection and localization of heterogeneities, we apply the method of mathematical focusing and technology of Synthetic Aperture Radar (SAR) where all the HF signals registered by the array are summed in phase for each specified focusing point with correction for the existing delay.
Thus, focusing is carried out by means of sequential summing of received signals with time delays equalization of the pulses scattered by the point with specified coordinates. Delays corresponding to the total time of the signal propagation from the transmitter to the object and back from the object to the receiver are introduced into the received signal. As next step amplitudes of the signals corresponding to calculated delays are summed up. The obtained result is a pixel/point of the radio-image with the appropriate coordinates. 3D image can be created by means of focusing for each point of the selected volume. Focusing is carried out in frequency domain with the use of the fast processing algorithms; thus, allowing real-time realization of 3D tomograms for the studied volume.