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

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.