OVERVIEW OF MODERN APPROACHES TO SOLVING THE PROBLEM OF EXTENDED RADAR TARGETS RECOGNITION

The development of the theory and technology of radio location indicates the need to solve problems of radar recognition of targets by spatial parameters. This is due to the need to provide in promising radar stations (complexes) with a software overview of the required resolution to obtain three-dimensional images in all spatial coordinates. The task of radar targets recognition, which is to assign the observed objects to the appropriate classes and types, is of considerable and growing interest. Different classes (types) of targets make up a certain alphabet, the choice of which determines not only the effectiveness of the use of recognition, but also the difficulties that arise in its implementation. Currently, there are a large number of radar recognition algorithms. They differ in the stages of decision-making, the degree and nature of accounting for statistics of signs, obstacles and signals. Due to the fact that the secondary emission pattern of extended targets is multi-lobed, statistical algorithms are preferred. The information used for radar recognition is contained in the set of received radar signals. However, most often for target recognition certain measured target features are used, which are compared in accordance with the recognition algorithms with known (reference) features. The choice of recognition features is usually made heuristically. This set of parameters does not always allow providing the required quality of recognition. The synthesized algorithms work unstable or require unreasonably large computational costs due to a significant increase in the dimensionality of the feature space. Analysis of known radar recognition algorithms of extended targets shows that they were developed under significant constraints. At present, the tasks of point targets radar surveillance are most fully solved. The tasks of processing signals reflected from bodies of complex shape, given the difficulties of their formulation and solution are not fully explored. It is promising to consider a set of radar surveillance tasks and the criteria used in them as a multicriteria task, the solution of which is associated with vector optimization of the location system as a whole.

Design and simulation of flexible jute antenna with performance validation on bending and soaking conditions

Recently, there has been an abrupt increase in the integration of community antenna to flexible, textile and wearable applications. The proposed work introduces the design of a flexible wearable patch antenna using a jute fiber substrate for better performance. The antenna has been designed and simulated with jute substrate at the operating frequency of 3.23 GHz. The antenna has been fabricated and tested under normal, wet, on-hand and bending conditions using a vector network analyzer. The various parameters such as reflection coefficient parameter and voltage standing wave ratio of the fabricated antenna are measured and compared with the simulation results. The tested results show that the performance of the antenna under normal, wet, on-hand and bending conditions is almost approximately equal. Due to better performance in soaking and bending conditions as well as low cost and adequate availability of jute material, the proposed antenna can be used in various applications such as biomedical, military, radio location, ground radar, search and rescue applications, and more.

A PRIVATE MODEL OF INDEX IS A HINDRANCE OF STABILITY OF THE STATION OF ACCOMPANIMENT OF AIM OF ZENITHAL ROCKET COMPLEX OF SHORTER-RANGE

Protecting from the action of radio of hindrances on the elements of zenithal rocket complex of shorter-range is one of important problems, that requires modern approach for her decision. Presently, influence of active hindrances is certain yet not enough on possibilities of armament on the defeat of air aims. In the article the analysis of influence of hindrances of different closeness is conducted on the station of accompaniment of aims of fighting machine of zenithal rocket complex shorter-range. The partial model of determination of index is offered hindrance of stability of the station of accompaniment of aim of zenithal rocket complex of shorter-range. The brought partial model over allows an analytical method to conduct the evaluation of values of conditional hit of model aim probabilities under various conditions. Mathematical calculations are conducted for: amplification of aerial of accompaniment of aim of fighting machine and aerials factors hindrance of producer; powers of hindrances on the entrance of accompaniment of aim of fighting machine; to the maximum sensitiveness of accompaniment of aim of fighting machine and relations hindrance/noise in the radio-location channel of accompaniment of aim; standard deviation of error of aiming of rocket depending on distance to the point of meeting of rocket with an aim in the zone of defeat taking into account influence of hindrances on the radio-location channel of accompaniment of aim of fighting machine; probabilities of passing of rocket in the «tube» of the set radius and conditional hit of aim probability at firing by one rocket; coefficient of зпомеха stability of accompaniment of aim of fighting machine; to conditional hit of aim probability hindrance of producer at firing by two rockets. On the accepted entry informative parameters and technical descriptions of accompaniment of aim of fighting machine certainly her maximum sensitiveness and relation hindrance/noise in this radio-location channel. On results mathematical calculations (mathematical design) corresponding charts that over is brought are got. From charts it is possible to define high efficiency of firing rockets on a model (air) aim.

Dual Band Compact Hexagonal Microstrip Antenna with Quadrangular Slot and I Shaped DGS

Here an hexagonal printed antenna is reported. The antenna has measurement volume of 800 mm 3 . It operates at the frequencies 2.9 GHz, and 6.3 GHz with S11 of -10.17 dB and -14.49dB respectively. It has produced acceptable gain of 2.065dB for 2.9 GHz and 3.45dB for 6.3 GHz. The frequencies obtained are useful for aeronautical radio location and satellite applications. The antenna is designed using HFSS software and tested using ZVH vector network analyzer.

Aircraft Trajectory Tracking Using Radar Equipment with Fuzzy Logic Algorithm

Radio-electronic means, including equipment for transmissions, radio-location, broadcasting, and navigation, allow the execution of various research missions and combat forces management. Determining the target coordinates and directing the armament towards them, obtaining and processing data about enemies, ensuring the navigation of ships, planes and outer atmospheric means, transmitting orders, decisions, reports and other necessary information for the armed forces; these are only some of the possibilities of radio-electronic technology. Fuzzy logic allows the linguistic description of the laws of command, operation and control of a system. When working with complex and nonlinear systems, it can often be observed that, as their complexity increases, there is a decrease in the significance of the details in describing the global behavior of the system. Even though such an approach may seem inadequate, it is often superior and less laborious than a rigorous mathematical approach. The main argument in favor of fuzzy set theory is to excel in operating with imprecise, vague notions. This article demonstrates the superiority of a fuzzy tracking system over the standard Kalman filter tracking system under the conditions of uneven accelerations and sudden change of direction of the targets, as well as in the case of failure to observe the target during successive scans. A cascading Kalman filtering algorithm was used to solve the speed ambiguity and to reduce the measurement error in real-time radar processing. The cascade filters are extended Kalman filters with controlled gain using fuzzy logic for tracking targets using radar equipment under difficult tracking conditions.