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• SIMULATION MODEL OF LOW-ALTITUDE METHOD OF PROFILING A REFLECTIVE SURFACE

  А.N. Bakumenko, V. Т. Lobach

  2025-01-30

  Abstract ▼

  The paper is devoted to the development and study of a new method for low-altitude surface profiling
  using a synthetic aperture radar (PCA), which allows obtaining high-resolution radar images both in
  range and along the track line. The paper examines in detail the theoretical foundations of PCA systems,
  the features of signal formation and processing, and the creation of a simulation model to test the effectiveness
  of the proposed method. The paper analyzes the basic principles of SAR systems, including the use
  of probing signals with linear frequency modulation (LFM). These signals play a critical role in achieving
  the high resolution required for high-quality display of small details on the earth's surface. The paper
  pays attention to taking into account the features of the SAR carrier's motion, such as its speed and flight
  altitude. These parameters have a significant impact on the quality of the obtained images, and their correct
  control can significantly improve the final result. The authors consider the influence of the wave
  phase front and the Doppler effect on the shape of the received trajectory signal. Understanding these
  processes is necessary for correct interpretation of data and improving the accuracy of radar images. The
  paper presents a developed simulation model in the MATLAB programming language, which allows simulating
  the operation of a radar and assessing the quality of the images obtained. This model is an important
  tool for testing and optimizing the proposed method. The paper provides examples of simulation
  results that confirm the performance and adequacy of the proposed model. These results show that the
  method is able to operate effectively even in difficult conditions and provide high-quality radar images.
  Thus, the article presents a new and promising method for low-altitude profiling of a reflective surface,
  which can be used in a variety of fields, including scientific research, environmental monitoring, agriculture,
  as well as military and civilian applications

• MODEL OF ALGORITHM FOR STREAMING LABELING OF WIDE FORMAT IMAGES

  А.N. Bakumenko, V. А. Derkachev, V.V. Bakhchevnikov, V.T. Lobach

  2024-05-28

  Abstract ▼

  This article proposes a wide-format image processing algorithm for use in systems operating in real
  time with a high-speed video data stream. The issue of image preprocessing, its clustering, segmentation
  and labeling is of particular importance for systems for processing high-resolution video streams in real
  time. In addition, when implementing such algorithms, there is an urgent issue of minimizing the cost of
  computational resources of programmable logic integrated circuits (FPGAs), on which the direct deployment
  of streaming image processing algorithms takes place. Minimal resource consumption is ensured by
  single-pass marking algorithms, which eliminate the need for image buffering, which is especially important
  when processing high-resolution wide-format images. However, when implementing a single pass
  of an image through the processing system, many additional markers may be created that are subject to
  further combining, especially when analyzing images with high resolution. The additional markers created
  require an increase in the requirements for the number of usable memory cells on the FPGA. The algorithm
  for streaming high-resolution wide-format images described in the article makes it possible to label
  high-resolution streaming video images, reducing the likelihood of creating additional tags that need to be
  further combined. The essence of improving the algorithm relative to the standard one-pass one is to add
  additional elements to the scanning mask, which avoid the appearance of different labels corresponding to
  the same object, which allows, with a minimal increase in the amount of memory used on the FPGA, to
  avoid duplication of labels and overuse of device memory. The algorithm was simulated for implementation
  on an FPGA using the Xilinx System Generator for DSP tool in conjunction with the Matlab Simulink
  environment for model-based design (MBD). The results of the algorithm are presented on images obtained
  from a high-speed linear camera TELEDYNE DALSA LA-CC-04K05B-00-R using the Integre
  Technologies LLC FMC-200-A mezzanine, as well as the Xilinx ZYNQ Ultrascale+ MPSoC ZCU106 development
  board.

• INTENSITY OF REFLECTED SIGNAL VOLTAGE FLUCTUATIONS AT SMALL IRREGULARITIES OF THE REFLECTING SEA SURFACE

  V.Т. Lobach, А.N. Bakumenko

  2024-01-05

  Abstract ▼

  The work is devoted to the study of reflections of electromagnetic fields from images corresponding
  to the limitations of the Kirchhoff method. An analysis of wave work known in the field of
  diffraction allows us to conclude that solutions to problems of diffraction of wave characteristics
  by uneven surfaces are reduced to one degree or another when deriving simplifying hypotheses.
  Among the main simplifications are: limitation of radiation areas and, as a theory, fixation of
  multipliers of integrated expressions, refusal to take into account the variability of local indicators
  of the Fresnel reflection coefficient, solution of a single-position problem of wave diffraction in
  conditions of combining points and reception, isotropic nature of the spatial structure of the reflecting
  surface. The work solves the problem of estimating the range of voltage fluctuations of a
  radar signal reflecting a small-scale rough sea surface, without accepting the main simplifying
  hypotheses. Based on the general solution for the scattering fields of the main polarizations obtained
  within the Kirchhoff method, analytical solutions for the intensity of fluctuations of the
  complex amplitude of the field and the power of the incoherent component of the reflected signal
  are analyzed. The relations obtained for the case of small heights of surface irregularities show
  their differences from the known results. Functional dependences of the intensity of fluctuations of
  the complex amplitude of the field and the power of the incoherent component on the electrical
  parameters of the reflecting surface, on the magnitude of the spatial separation of the transmitting
  and receiving antennas, on the wavelength and length of sea wave crests, on the width of the antenna
  radiation pattern (APP) and on the magnitude of the surface inclinations were obtained.
  Spatial separation of the transmitting and receiving antennas reduces the amount of power of the
  incoherent component. The effect of diversity weakens as the beam expands and the flight altitude
  increases. As the length of sea waves and the length of sea wave crests increase, the degree of
  their influence on the power of the incoherent component weakens. It also weakens as the width of
  the bottom expands and with a decrease in the radio wavelength. It is shown that in the decameter
  range of radio waves, taking into account the slopes of the surface leads to a change in the intensity
  of fluctuations of the reflected signal by a few percent only at sea wavelengths approaching the
  radio wave length.