Recognition of radar images generated by synthetic aperture radar systems

In the field of radar remote sensing of the Earth, the problem of detecting and / or identifying spatially distributed targets against the background of a homogeneous surface is becoming increasingly important, for example, the tasks of the coast guard, monitoring of unauthorized forest logging, assessing the consequences of natural disasters, and others. This study is devoted to solving the problem of developing the optimal algorithm for making a decision on the class of a spatially distributed target based on data from side-scan radar systems with a synthetic aperture. A detailed description of the signal formation process in the fixed range channel is given, taking into account possible interference factors. Based on the statistical criterion by the method of maximum likelihood, the recognition algorithm is proposed, expressions for the formation of a feature vector are obtained, and the nonparametric decision rule is proposed. The algorithm has been tested on the example of recognizing three classes of spatially distributed targets that differ in size.

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Results of inverse synthesis of two-dimensional radar images of objects with autofocusing in wide sectors of angles.

Journal of Radio Electronics ◽

10.30898/1684-1719.2020.11.8 ◽

2020 ◽

Vol 2020 (11) ◽

Author(s):

S.I. Moryakov ◽

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S.M. Nesterov ◽

I.A. Skorodumov ◽

◽

...

Keyword(s):

High Resolution ◽

Synthetic Aperture Radar ◽

Large Angle ◽

Synthetic Aperture ◽

Synthetic Image ◽

Wide Angle ◽

Two Dimensional ◽

Radar Images ◽

Radar Systems ◽

Wideband Radar

Modern wideband radar systems makes possible to obtain high resolution inverse synthetic aperture radar images of objects. One of the difficult actual approaches in radar test facilities is wide angle autofocusing processing. This paper proposed a recommendations to wide angle (above 10 degrees) inverse synthetic image autofocusing processing based on dividing a large angle sector into several small sections. Also proposed an experimental results of autofocusing processing in 30° and 60° angle sector.

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Comparative Analysis of Frequency Scaling Algorithms for Signal Processing in Small-Size Mobile Platforms

Transportation systems and technology ◽

10.17816/transsyst20173442-74 ◽

2017 ◽

Vol 3 (4) ◽

pp. 42-74

Author(s):

Zhargal T Erdyneev ◽

Andrey A Geltser ◽

Elena P Velikanova ◽

Nikolay V Panokin

Keyword(s):

Synthetic Aperture ◽

Frequency Scaling ◽

Mobile Platforms ◽

Basic Algorithm ◽

Radar Images ◽

Radar Systems ◽

Mathematical Formulas ◽

The Difference ◽

Synthetic Aperture Radars ◽

Scaling Algorithms

Introduction. With the development of hardware and computer systems, which improve qualitative characteristics of synthetic aperture radars, with their dimensions limited, many new systems have appeared that allow using more accessible and widespread mobile platforms such as a car, quadcopters, unmanned aerial vehicles (UAV). Problem. The use of new types of platforms leads to additional distortions associated with features of the geometry of the radar performance and more severe trajectory instabilities. Thus, new synthetic aperture radar systems should have special requirements for both software and hardware, which differ from classical systems. Objective. The aim of the work is the comparison various algorithms that are used in modern radiovision systems to obtain high-quality radar images that can be integrated into various kinds of mobile platforms. Methods. The method of frequency scaling and various modifications of this method are taken as a basic algorithm, including additional algorithms for compensating trajectory instabilities. For comparison of algorithms, the system geometry for automobiles and aircraft systems are considered and simulations were performed with the presence of point reflectors at different distances and the distortion of the platform motion. Results. The difference of the considered algorithms in the form of flowcharts and mathematical formulas is shown. Based on results of the simulation the use of the basic frequency scaling algorithm at distances corresponding to the geometry of the automobile system leads to the distortion of the response along the azimuth. In addition, the use of the modified algorithm for compensating trajectory distortion allows correct focusing the targets at different distances. Conclusion. The proposed combination of modified algorithms of trajectory distortion and frequency scaling allows focusing the image evenly throughout the frame and improving the quality of the image in the near zone.

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Modelling complex for surface radar images in the “distance-angle” coordinates

ITM Web of Conferences ◽

10.1051/itmconf/20193015011 ◽

2019 ◽

Vol 30 ◽

pp. 15011 ◽

Cited By ~ 2

Author(s):

Yury Markov ◽

Alexander Bokov ◽

Vladimir Vazhenin

Keyword(s):

Electromagnetic Waves ◽

Single Channel ◽

Antenna System ◽

Synthetic Aperture ◽

Front Side ◽

Software Complex ◽

Radar Images ◽

Radar Systems ◽

Different Types ◽

Synthetic Aperture Radars

The mathematical modelling software complex of monostatic radar systems is discussed in the article. It is aimed to model of typical radar scenarios with various conditions of an electromagnetic waves reflection from terrain. The received signals are used to synthesize radar images (portraits) of surfaces. The structure of the modelling complex allows studying of single-channel and multi-channel synthetic aperture radars with pulse and continuous types of modulation of signals reflected from underlying surfaces of different types. The complex can be useful to simulate radar portraits of the surrounding radar scene’s objects in the native “distance-angle” coordinates, including the nadir direction of the antenna system. The portraits for cases of front-side looking by a wide- pattern antenna in two adjacent directions are modelled and evaluated in the article.

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