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• RESTORATION OF DEFECTS AND BLIND ZONE ON IMAGES OF UNDERLYING SURFACE FOR ONBOARD RADAR SYSTEMS OF MAPPING BASED ON DOPPLER BEAM SHARPENING

  R.R. Ibadov, S.R. Ibadov, V.P. Fedosov

  2021-02-13

  Abstract ▼

  The problem of forming a radar image (RI) of the earth's surface in real time remains one of
  the most urgent in solving radio imaging problems, despite the appearance of a large number of
  publications in this area, reflecting a whole range of new methods and algorithms for processing
  trajectory signals in order to improve the quality of images. The main goal in the formation of
  radar images is to achieve the maximum resolution and image quality under real constraints associated
  with the drift of the parameters of the received trajectory signal (synthesis time), measurement
  inaccuracy and variability of flight characteristics (speed, acceleration, flight trajectory),
  exposure to a wide range of noise and interference, both external and internal, against the background
  of a low-power received signal from remote radio reflectors (energy resources). The article
  investigates an algorithm for constructing and restoring images of the underlying surface and
  develops its software implementation. The effectiveness of the new approach is shown using several examples for various areas of the underlying surface with a blind spot. The subject of the research
  is methods and algorithms for constructing a terrain map and reconstructing lost image
  areas. The research object is a set of test images. The result of the research is the development of a
  method for image restoration in order to restore the lost area. The novelty of the work is an algorithm
  that improves the quality of image restoration based on a neural network. The results obtained
  make it possible to restore the areas. Evaluation of the efficiency of the image restoration
  method was carried out using a statistical criterion - the root mean square error of the processing
  result from the true image. As a result of solving the tasks, we can draw conclusions:  A method
  was developed for constructing and restoring images of the underlying surface based on the
  search for similar blocks with their subsequent combining by a neural network.  Analysis of the
  results of the study showed that the proposed method improves the quality of image reconstruction.

• ANALYSIS OF UNDERLYING SURFACE IN IMAGE FORMATION IN DOPPLER BEAM SHARPENING MODE

  R.R. Ibadov, V.P. Fedosov, S.R. Ibadov

  2022-11-01

  Abstract ▼

  Radar based on real beam scanning is widely used in both civil and military spheres. However,
  it is difficult to realize high azimuth resolution of a stationary platform or a platform with nonuniform
  motion using conventional signal processing algorithms. Doppler beam sharpening (DBS)
  technology is a combination of high resolution and real-time performance compared to Synthetic
  Aperture Radar (SAR) technology, which uses the Doppler shift between echoes from objects on the
  underlying surface along the azimuth direction, caused by the movement of the radar platform. Unfortunately,
  the traditional DBS imaging algorithm, which constructs a Doppler filter using an FFT,
  has a low azimuth resolution and a high level of side lobes, which limits further improvement in azimuth
  resolution. In the article, the algorithm for constructing a map of the underlying surface in the
  direction of movement of the radar carrier based on the DBS was studied and the map image was
  analyzed using the Fourier transform. A three-dimensional view of the map of the underlying surface
  is shown with the distribution of values in the images. The subject of the study is the method and algorithm
  for constructing a map of the underlying surface in the Doppler beam sharpening mode and
  identifying chain structures based on the analysis of the Fourier transform. The object of the study is

  a set of test images of the terrain map. The result of the study is the development of an algorithm for
  constructing a map in order to identify chain structures on the underlying surface. The novelty of the
  work is an algorithm that allows you to build a map of the underlying surface based on the DBS,
  taking into account the blind zone in the direction of movement of the radar carrier. The results obtained
  also make it possible to reveal chain structures in the region of interest. The possibility of
  estimating the periodicity of image elements using the Fourier transform has been tested. As a result
  of solving the tasks set, the following conclusions can be drawn: – an algorithm has been developed
  for constructing a map of the underlying surface based on DBS with image correction in the direction
  of movement of the radar carrier. – analysis of the results of the study showed that the proposed algorithm
  allows you to identify chain structures on the map.