The problem of developing the architecture of modern cognitive radar system

The problem of developing the architecture of modern cognitive radar systems using artificial intelligence technologies is considered. The main difference from traditional systems is the use of a trained neural network. The heterogeneous multiprocessor system is rebuilt in the process of solving the...

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spelling pp_isofts_kiev_ua-article-4902022-07-12T19:40:17Z The problem of developing the architecture of modern cognitive radar system Проблеми розробки архітектури сучасних когнітивних радіолокаційних систем Коsovets, M. Tovstenko, L. Perception-Action Cycle;Artificial Intelligence; Signal to Noise Ratio; Active Electronically Scanned Array;Environmental Dynamic Database; Signal to Noise Ratio; Radar Resource Management; multiprocessor UDC 517.9:621.325.5:621.382.049.77 штучний інтелект; нейронна когнітивна мережа; сенсорні мережеві додатки УДК 517.9:621.325.5:621.382.049.77 The problem of developing the architecture of modern cognitive radar systems using artificial intelligence technologies is considered. The main difference from traditional systems is the use of a trained neural network. The heterogeneous multiprocessor system is rebuilt in the process of solving the problem, providing reliability and solving various types of problems of one class and deep learning of the neural network in real time. This architecture promotes the introduction of cognitive technologies that take into account the requirements for the purpose, the influence of external and internal factors.Problems in programming 2022; 4: 75-86 Розглянуто проблему розробки архітектури сучасних когнітивних радіолокаційних систем із використанням технологій штучного інтелекту. Основною відмінністю від традиційних систем є використання навченої нейронної мережі. Гетерогенна багатопроцесорна система перебудовується в процесі розв’язування задачі, забезпечуючи надійність і вирішення різних типів задач одного класу і глибоке навчання нейронної мережі в режимі реального часу. Така архітектура сприяє впровадженню когнітивних технологій, які враховують вимоги по призначенню, вплив зовнішніх і внутрішніх факторів. Глибоке навчання нейронної когнітивної мережі радарних датчиків є функцією штучного інтелекту, який моделює роботу людського мозку таким чином, що обробляє дані та створює шаблони, які використовуються у прийнятті рішень. Система виявлення вчиться виявляти зміни не тільки в рівнях сигналу, а й у формі та параметрах сигналу. Експерименти показали, що система виявлення змін радіолокаційної інформації на основі нейронної мережі з глибоким навчанням є оптимальною для розробки сенсорних мережевих додатків і може бути успішно реалізована на доступних технологічних платформах.Problems in programming 2022; 4: 75-86 PROBLEMS IN PROGRAMMING ПРОБЛЕМЫ ПРОГРАММИРОВАНИЯ ПРОБЛЕМИ ПРОГРАМУВАННЯ 2022-05-30 Article Article application/pdf https://pp.isofts.kiev.ua/index.php/ojs1/article/view/490 10.15407/pp2022.01.075 PROBLEMS IN PROGRAMMING; No 1 (2022); 075-086 ПРОБЛЕМЫ ПРОГРАММИРОВАНИЯ; No 1 (2022); 075-086 ПРОБЛЕМИ ПРОГРАМУВАННЯ; No 1 (2022); 075-086 1727-4907 10.15407/pp2022.01 en https://pp.isofts.kiev.ua/index.php/ojs1/article/view/490/489 Copyright (c) 2022 PROBLEMS IN PROGRAMMING
institution Problems in programming
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datestamp_date 2022-07-12T19:40:17Z
collection OJS
language English
topic Perception-Action Cycle;Artificial Intelligence
Signal to Noise Ratio
Active Electronically Scanned Array;Environmental Dynamic Database
Signal to Noise Ratio
Radar Resource Management
multiprocessor
UDC 517.9:621.325.5:621.382.049.77
spellingShingle Perception-Action Cycle;Artificial Intelligence
Signal to Noise Ratio
Active Electronically Scanned Array;Environmental Dynamic Database
Signal to Noise Ratio
Radar Resource Management
multiprocessor
UDC 517.9:621.325.5:621.382.049.77
Коsovets, M.
Tovstenko, L.
The problem of developing the architecture of modern cognitive radar system
topic_facet Perception-Action Cycle;Artificial Intelligence
Signal to Noise Ratio
Active Electronically Scanned Array;Environmental Dynamic Database
Signal to Noise Ratio
Radar Resource Management
multiprocessor
UDC 517.9:621.325.5:621.382.049.77
штучний інтелект
нейронна когнітивна мережа
сенсорні мережеві додатки
УДК 517.9:621.325.5:621.382.049.77
format Article
author Коsovets, M.
Tovstenko, L.
author_facet Коsovets, M.
Tovstenko, L.
author_sort Коsovets, M.
title The problem of developing the architecture of modern cognitive radar system
title_short The problem of developing the architecture of modern cognitive radar system
title_full The problem of developing the architecture of modern cognitive radar system
title_fullStr The problem of developing the architecture of modern cognitive radar system
title_full_unstemmed The problem of developing the architecture of modern cognitive radar system
title_sort problem of developing the architecture of modern cognitive radar system
title_alt Проблеми розробки архітектури сучасних когнітивних радіолокаційних систем
description The problem of developing the architecture of modern cognitive radar systems using artificial intelligence technologies is considered. The main difference from traditional systems is the use of a trained neural network. The heterogeneous multiprocessor system is rebuilt in the process of solving the problem, providing reliability and solving various types of problems of one class and deep learning of the neural network in real time. This architecture promotes the introduction of cognitive technologies that take into account the requirements for the purpose, the influence of external and internal factors.Problems in programming 2022; 4: 75-86
publisher PROBLEMS IN PROGRAMMING
publishDate 2022
url https://pp.isofts.kiev.ua/index.php/ojs1/article/view/490
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fulltext 75 Моделі та методи машинного навчання Introduction Modern radar systems operate in a wide variety of dynamically changing sce- narios: the detection, tracking and classifi- cation of very small and slow targets. Such objects as drones, missiles, boats, along with a complex spectrum are important system requirements. Cognitive radars, combining many well-known and new methods, offer a promising solution to these problems. We consider the functional architecture of cog- nitive radar from the perspective of the user and the manufacturer. Cognitive radar is an updated tech- nology, the origins of which go back to sci- ence - «cybernetics», human-machine inter- action, signal processing. The evolution of cognitive radar is aimed at achieving cogni- tion, as in its natural counterparts, such as the radar capabilities of bats and dolphins, or human intellectual decision-making. This article provides an overview and trends in the development of cognitive radar systems. Organization of cognitive computing The term «cognitive radar» was first introduced by Dr. Simon Haikin [1], follow- ing the ideas of cognitive neurology, which is based on works of cybernetics, artificial neural networks, self-organized learning and solutions of Bayesian theory. Engineer- ing analogues for the implementation of the main cognitive features identified by Faster: memory, attention and intelligence (PAC Perception-Action-Cycle: Cycle-per- ception-action) have been proposed [2]. In studies of cybernetics, Rasmussen [3], [4] described human behavior in terms of three levels: based on skills, rules and knowledge. He described behavior-based behavior as a subconscious that reflects basic signal pro- cessing and generation blocks in a radar system [5]. Rule-based behavior is used in familiar situations. The basis of parallel work is modeling and analysis of previous experience. Build cognitive radar developers have inspired research in the field of bio- mimetics. Artificial intelligence is modeled on the basis of observations of living intel- ligence. Thus, masters of echolocation - bats and dolphins can detect and track very small prey, using complex waveforms that are changed dynamically [6]. Moreover, knowledge of the intelligence of living be- ings allows us to better understand living nature. It helps to create artificial intelli- gence, which is superior to «living» and is used in technical systems. Information in the radar system is perceived by «smart» sensors, i.e. sensors with primary processing and control of the measurement process [7], as well as through network sensors that demonstrate «distrib- УДК517.9:621.325.5:621.382.049.77 http://doi.org/10.15407/pp2022.01.75 M. Коsovets, L. Tovstenko THE PROBLEM OF DEVELOPING THE ARCHITECTURE OF MODERN COGNITIVE RADAR SYSTEM The problem of developing the architecture of modern cognitive radar systems using artifi cial intelligence technologies is considered. The main diff erence from traditional systems is the use of a trained neural network. The heterogeneous multiprocessor system is rebuilt in the process of solving the problem, providing reliability and solving various types of problems of one class and deep learning of the neural network in real time. This architecture promotes the introduction of cognitive technologies that take into account the requirements for the purpose, the infl uence of external and internal factors. Keywords: Perception-Action Cycle, Artifi cial Intelligence, Signal to Noise Ratio, Active Electronically Scanned Array, Environmental Dynamic Database, Signal to Noise Ratio, Radar Resource Management, multiprocessor. © M. Коsovets, L. Tovstenko, 2022 ISSN 1727-4907. Проблеми програмування. 2022. № 1 76 Моделі та методи машинного навчання uted intelligence» with self-monitoring ca- pabilities, automatic solution of changes in their environment [8] , [9]. Cognitive radar has the ability to adapt to transmission in the probing process, imitating human per- ception as an interactive process where the cognitive entity responds to or changes its behavior as a result of external stimuli. In traditional radar systems, the flow of information is one-way: the radar inter- rogates the environment by transmitting a fixed, predetermined pulse signal, regard- less of any changes in the environment. Adaptive processing is performed on recep- tion, but the results of such processing do not control any radar function for transmis- sion. An overview of the cognitive direc- tions of radar construction research over the last decade gives an idea of the methods being developed for a wide range of radar applications. Technical problems in the de- velopment of cognitive radars are the moti- vation for further work in this area. Central to these works is the idea of closed-loop data collection, where the dynamic state is interpreted as an adaptive measurement determined by Kalman filtering. This ap- proach allows the antenna array to be adap- tively directed in the direction and width of the beam, as well as to place zeros so as to reject any unwanted signals or noise outside the main particle. A database of problems has been developed that allows comparing methods that use beam control of phased array an- tennas to optimize tracking, minimizing false alarms [10], [11]. Sometimes several hypotheses and filtering interactions of sev- eral tracking models are tested [12-13] to optimize performance: such as signal-to- noise ratio, interference effects, track, and detection threshold. Common features of increasing adaptability: prediction of adaptive sched- uling review time, adaptive choice of de- tection thresholds (eg, constant false alarm rate detectors) [14], and adaptive interfer- ence suppression using adaptive-spatio- temporal processing mode [15] to improve target detection. Adaptive tracking meth- ods vary the measurement time, as well as the signals used to update the trajectory, based on the measurements obtained by the tracker. This feedback is used to control the radar so that frequent measurements are made during an unpredictable or rapid dynamic maneuver, while infrequent mea- surements are made during predicted peri- ods or steady dynamics. The simultaneous change of intra- pulse signal modulation is studied on the basis of the provided measurements on the tracker. This leads to the choice of optimal signal methods [16-17] and their adaptive extensions [18-19]. Optimization of radar signal in dynamics, to maximize perfor- mance according to specific scenarios and tasks, includes the use of some components of radar, such as antenna, radiation pattern (both transmission and reception), time, frequency, coding and polarization. The signals are selected from several classes of signals, such as linear or nonlinear fre- quency modulation, phase or encoding fre- quency, and ultra broadband signals. This also includes adapting parameters within the signal class, such as changing the pulse repetition interval, bandwidth, or center frequency [20]. The optimal signal, which maximizes the signal / noise, arises as a so- lution of the generalized eigenvalue on the waveform [21], developing in the frame- work of «joint optimization of transmission and reception by the choice of waveform. The approach was used in Bayesian theory of decision making and development, de- signed to optimize the system by selecting the signal at the transmitter and minimiz- ing interference at the receiver. There are also difficulties in choosing the criteria of optimality and accurate distribution of in- terference. According to the IEEE, the defini- tion of «cognitive radar» is a radar that has the ability to learn: «Radar system, which automatically generates a constant percep- tion of the target scene and takes appropri- ate action. It can use short-term and long- term memory to increase the performance of a given function. Compared to adaptive radar, cognitive radar is trained to adapt operating parameters as well as processing parameters, and can do so over longer pe- riods of time.” 77 Моделі та методи машинного навчання Fig.1. FMCW Radar Imaging Cognitive Ability Modeling Complex with Deep Learning Package. Cognitive radar diff ers from traditional active radar due to the following features: de- velopment of rules of conduct for self-orga- nization through a process called experiential learning, which is the result of long-term in- teraction with the environment. According to Charlish, cognitive radar is a radar system that acquires knowledge and understanding of the work environment through online assessment and training from databases that contain con- textual information. Cognitive radar uses this knowledge to improve information: search, data processing and management of radar re- sources. With the development of cognitive radars began a new era in the creation of mod- ern radar systems. The number of publications on the development of cognitive radar archi- tecture with artifi cial intelligence is increas- ing avalanche. Artifi cial intelligence is used in the construction of neural networks, methods of deep learning, signal processing, pattern recognition, classifi cation. It should be noted that elements of cognition in the construction of radars have always been presented (power, pulse width, repetition rate, modulation, etc.). There is also the ideology of the neural net- work, and accordingly their in-depth training (multiprocessor with restructuring). The ex- plosive growth of the latest developments in radar systems is related to public demand (de- fense, security, medicine, subsurface sound- ing, mine search, unmanned aerial vehicles) and the ability to meet them: the use of artifi - cial intelligence technology and the develop- ment of a new component base. Cognitive radar methods use mimic elements of human cognition, such as the cycle of perception-action, deep learning, in- telligence and the use of existing knowledge [22]. Cognitive radar vision methods use ra- dar spectrum [23], [24], radiation optimiza- tion [25], tracking [26-28], beam control [29], interference reduction [30], network [31], re- source management [32] . To develop a cognitive radar system that adapts in real time, the multiprocessor must be an integral part of the simulation tool. It helps to analyze the behavior of the radar at the simulation stage. The post-process stage consists of two steps. In the fi rst step, a radar sensor and a proven circuit are developed us- ing non-adaptive settings. In the second step, the multiprocessor is tested and confi gured, replacing the Front-end sensor. Pre-recorded raw datasets that include all radar parameters are optimized. Such datasets use the same measurement for all parameters of environ- ment, target, and trajectory. At this stage of development, the feedback cycle is closed by obtaining an interval of coherent processing of raw data relating to the selected optimal pa- rameters in real time. The modeling complex consists of an adaptive radar sensor that perceives the environment with optimized radar param- eters and a multiprocessor that tracks the target and selects the optimal radar param- eters for each new measurement. The sensor consists of an adaptive signal generator, a radar interface, an ADC and a real-time sig- nal converter and a display. The controller consists of a Kalman filter tracker and an optimizer that selects both optimal signals and real-time processing parameters based on the latest measurements. Multiprocessor processing is simulated in Matlab and runs on an Ubuntu Linux PC. The radar data processing system consists of three modules: FPGA, worksta- tion and graphics processing unit. FPGA provides primary signal processing and hardware management. Its most important role in signal processing is to perform digi- tal down-conversion of the received signal so that the true baseband can be transmitted to the workstation for further processing. Subsequent implementation of the appro- 78 Моделі та методи машинного навчання priate fi lter on the FPGA can be useful for freeing resources on the graphics processor for its other tasks: fi ltering, discrete Fourier transform, and processing the constant rate of false alarms (CFAR). The detection task is implemented on a graphics processor. The CPU is an Intel multi-core processor. LabView National Instruments sup- port control functions. In addition, LabView can be used to write FPGA software. Simula- tion on FPGA Xilinx, RF-path on on-a-chip is used. The shell is written in Python for the C ++ library. Algorithms are tested on fl ex- ible radar equipment. We use digital trans- ceiver systems - such as Universal Software Radio Peripheral (USRP). In recent years, research on cognitive radar design has been conducted covering a wide range of programs, using many diff er- ent methods based on previous advances in Bayesian theory, information theory, theoret- ical solutions, approaches, including fuzzy logic, rule-based systems, metaheuristic al- gorithms and Markov solutions. processes, dynamic programming, optimization and game theory. Future systems are learning the abil- ity to predict the behavior of radars in the operational environment and to adapt its transmission in the available spectrum. Ra- dar cognition in this case is based on two main concepts: spectrum probing and spec- trum distribution. The sounding spectrum is aimed at recognizing the frequency used by other systems and occupying the same spec- trum in real time. System performance is measured in terms of standard metrics such as target de- tection probability and false alarms, root mean square error in tracking systems, and classifi cation accuracy in automated target recognition systems - cognitive systems re- quire additional metrics that quantify perfor- mance gains and achievement use of system resources. Two key issues for cognitive radar research are the development of assessment and assessment tools, as well as experimental testing of the methodology. A related but unique problem with the cognitive design of radar is experimental testing, as the shape of the transmitted signal and the settings are adapted during opera- tion. With more sophisticated modeling, new development and qualifi cation processes can be developed, including software testing that will help test cognitive radars. Cognitive radars are evaluated through simulations, or using pre-recorded data. The infrastructure of testing, calibra- tion and debugging tools is being developed in parallel. For example, SPC Quantor has developed real-time tests for cognitive ra- dars. Reliability of modeling and compu- tational errors is an important issue that should be investigated [33]. Radars differ in their qualitative and quantitative parameters. A typical approach is to determine the number of worst cases and make them work in the worst cases. This is true for non-cognitive radar systems that do not change the configuration depending on the current environment, because a sin- gle radar configuration is used. Cognitive radars change their configuration, rebuild- ing the neural network and learning or self- learning to solve various problems within certain limits. Moreover, with the develop- ment of neural network design tools, cogni- tive radars will have better characteristics and lower design costs and the ability to self-improvement. The power of the transmitter should not exceed the limits imposed by regulatory requirements, because there is unwanted ra- diation due to the nonlinearity of the transmit- ter and a sharp increase and decrease in radar pulses [34]. Especially in cognitive systems, dynamic reconfi guration of the transmission spectrum is not always easy to implement and can lead to out-of-band transmissions, which cause a slight spectral expansion outside the designated radar band. Cognitive radar architecture The cognitive radar architecture is built through the extension of the perception- action cycle by introducing an evaluation process that forms a perception-evaluation- action cycle (PEAC). The purpose of this ad- ditional step is to emphasize the assessment of the currently perceived situation supported by artifi cial intelligence. It is done regarding the purpose of the sensor and depends on the purpose certain perception results will lead 79 Моделі та методи машинного навчання to very diff erent actions, such as observation, where the overall picture is important. When observed, all identifi ed targets will receive an equal share of available resources. Fig.2. Functional diagram of the cognitive radar. The radar sensor, which operates in PEAC, consists of a programmable sensor that provides data processing and data evaluation, and management of resources generated de- pending on recently received environmental information. In future systems, much of the intelligence will be located in a multiplatform cloud. Cognitive radar responds intelligently to real-time scenario variations. A software-defi ned sensor is a system that performs radar measurements, ie emits, receives and processes electromagnetic sig- nals in accordance with the requirements of the sensor in order to obtain new informa- tion in its environment. A software-defi ned sensor requires hardware capabilities (eg, in- stantaneous bandwidth, operating bandwidth, waveform, polarization, etc.) to meet resource management requirements. Radio compatibility is achieved by methods relating to the emission of radar sig- nal or signal processing. Methods of reduc- ing interference from other radio frequency systems are achieved by dividing in time, fre- quency, space or signal modulation. Consider the main measures that allow coexistence: waveform, illumination in radar images, adaptive zeroing of interference, frequency adaptation, dynamic adaptation of the search circuit and the level of radiation power, de- tection of interfering samples in the receiving signal, suppression of interfered samples in the radar signal [35]. A Doppler shift around a target ap- pears if the target contains moving, vibrat- ing, or rotating parts and can be observed externally. For example, the wings of birds, the wheels of cars, the arms and legs of peo- ple walking, as well as the rotors of helicop- ters and tank tracks have a unique Doppler spectrum, which is observed using a radar system with a fairly high Doppler resolu- tion. The spectrum of Doppler shift strongly depends on such parameters as the angle of illumination, the absolute velocity of the target and the composition of the underly- ing surface. To adjust the detection thresholds ac- cording to the actual background, it is nec- essary to determine and assess the level of interference. This assessment can be per- formed on a one-time basis or over a long period of time by studying the characteristics of the obstacles. The mapping features can be characterized by its spatial composition, amplitude statistics and Doppler spectrum. This allows you to reliably adjust the detec- tion thresholds according to the character- istics of the interference, while maintaining a low level of false positives and providing the ability to detect targets against the back- ground of interference. Multi-beam radiation on the sea surface is characteristic of marine radars. The imposi- tion of a direct and refl ected path on the sea surface leads to the appearance of zones with attenuation and loss of target detection, as well as to errors in altitude measurement. By detecting fading situations, tracking can be more resistant to detection errors by changing the transmission frequency and thus avoiding the fading situation. Active grating and electronic scanning antennas, which are the latest in modern radar systems, provide great fl exibility in the direc- tion of the beam and waveforms. The various actions that require re- sources from the system are called tasks. Each task is an implementation of the radar func- tion that the sensor is capable of. Examples of such tasks: search tasks, tracking tasks, classifi cation tasks, visualization tasks, envi- ronmental detection tasks, externally assigned search and tracking tasks ordered by a higher system. QoS resource management techniques use quality measures to optimize overall sys- 80 Моделі та методи машинного навчання tem performance for this metric and avail- able resources. Therefore, this approach requires a good understanding of the qual- ity measures used. Especially when a large number of diff erent tasks are used, which will certainly be the case in future cognitive radars, it is necessary to fi nd a strong bal- ance between individual tasks and mission needs. The advantage of the QoS approach is that even in dense scenarios, the available re- source is distributed among the tasks still to maximize system performance, and no pre- determined priority, which may or may not be applied in the current situation, should be used to resolve confl icts. However, adaptive rules as well as the QoS approach require more environmental information to adapt the waveform to the evolving situation, taking into account the various infl uences imple- mented in the model used to assess the ex- pected performance of the system. In addi- tion, for QoS it is necessary to keep a list of all active tasks of the radar sensor. The hardware capabilities needed to take advantage of modern resource manage- ment capabilities are high if you use the full potential of algorithms. In this case, you need a fully fl exible interface that allows you to confi gure all available parameters (such as waveform, parameters, and viewing direc- tions) within the physical boundary of the external interface. However, to speed up the process of optimizing resource management, the available degrees of freedom can be lim- ited in advance, for example, by limiting the repetition rates of the selected pulses. If the limit is chosen adequately, the decrease in productivity is insignifi cant. Deep learning of the cognitive radar neural network Probably, today only the lazy are not engaged in machine learning. But when we look at cognitive radar software, we are talk- ing about deep learning. This is when the feedback covers the entire radar. The backpropagation algorithm is an extension of the perception of multilayer neural networks. Thus, the backpropagation algorithm uses three or more levels of pro- cessing units (neurons). In a typical 3-tier network architecture for a backpropagation algorithm, the leftmost layer of ones is the input layer that receives the input data. Lat- er, this is a hidden layer, where processing blocks are linked to the layers before and af- ter it. The rightmost layer is the output layer. The levels are fully interconnected, which means that each processing unit is connected to each unit at the previous level and at the next level. However, the units are not linked to other units in the same layer. Backpropa- gation networks are not fully interconnected, which means that any number of hidden lay- ers can be used. [31]. Traditional event detection in cogni- tive imaging radar is based on batch or offl ine algorithms: it is assumed that there is one event in each radar information stream. The stream is usually processed using a prepro- cessing algorithm that requires a huge amount of computation. Neural networks can eas- ily cope with such tasks with the appropriate deep learning. This is an analogue of infor- mation processing tasks “on the fl y” as they become available. Neural networks are also an eff ective method for diagnosing faults based on non- linear mapping of input and output data, par- allel processing and a high degree of self-or- ganization and self-learning ability [36]. In the structure of closed-loop neural networks the only suitable connections are between the outputs of each level and the input of the next level [37]. A backpropagation neural network is one known method for creating a trained machine or system that can provide a fi nal classifi cation decision through a series of learning processes. It can be developed using the tools provided in MATLAB, but sometimes this leads to diff erent detection and recognition accuracy of objects for each experiment [30–31]. We achieve troubleshooting by rebuild- ing the computational resource of the neural network. Moreover, a quick response occurs by changing the course of the computing pro- cess and in case of failures, readjustment of the network with a change in its resource. It is possible to draw an analogy with a living intellect, where homeostasis is provided at the hormonal level and a quick response to changes in the external environment by ner- vous signaling. 81 Моделі та методи машинного навчання We always willingly or unwillingly use bionic models. Now it has resulted in a separate science of imitation of nature - bio- mimetics. Creating a model in biomimetics is half the battle. To solve a specific prac- tical problem, it is necessary not only to check the presence of the model properties of interest to practice, but also to develop methods for calculating the predetermined technical characteristics of the device, to develop synthesis methods that ensure the achievement of the indicators required in the problem. And therefore, many bionic models, before they receive technical implementa- tion, begin their life on a computer. A math- ematical description of the model is con- structed. Based on it, a computer program is compiled - a bionic model. On such a computer model, various parameters can be processed in a short time and design flaws can be eliminated. Traditionally, deep learning algorithms update the weight of the network, while the architecture of the network is selected manu- ally using the trial-and-error method. This study proposes two new approaches that auto- matically update the structure of the network, as well as studying its weight. The novelty of this approach is parameterization, where depth or additional complexity is constantly encapsulated in the space of parameters that give additional complexity. Deep learning includes several levels of nonlinear information processing. This al- lows us to study architectures that implement functions through repetitive compositions of simpler functions, thereby exploring levels of abstraction with the best generalization and representation. Although in-depth training is useful, keeping multiple layers can be problematic. First, when more layers, weight, space, and computational complexity are higher; second, when there are more free parameters, there is a higher risk of retraining; third, if the net- work is deep, there is the problem of disap- pearing gradients when the error spreads over many layers. There have been many approaches to optimizing the network architecture - from early incremental methods of bringing hid- den modules one after the other (or start- ing from a large network and reducing it) to more sophisticated modern approaches such as evolutionary algorithms or reinforced learning and stimulus style techniques. The purpose of the study is to study network ar- chitecture based on data. The main differ- ence is that instead of searching in discrete space for all architectures that have param- eterized models in such a way that the very notion of complexity or depth is itself con- tinuous, making the model differentiated from beginning to end. Two methods are proposed for con- structing and studying the structure of a deep neural network, where the complexity of the network at the level of a hidden block or layer is encoded by continuous parame- ters. These parameters are adjusted together with the network weights during the gradi- ent descent, which implies a slight change in the structure of the network together with the network weights. The first method in tunnel networks associated with each hid- den block is a continuous parameter. If this parameter is not active, the block simply copies its input to its output to bypass non- linearity, effectively increasing the depth of the network. In the second method, the per- ceptron has parameters associated with each layer, indicating whether further nonlinear processing is required. We start with one layer first, and when training with a gradient descent, when necessary, this parameter can become active, which causes the creation of another complete layer, increasing the depth of the network. Experiments on synthetic double- helix data like tunnel networks and novice perceptrons can be adapted to different sizes for different complexity of problems using the same set of hyperparameters, adapting the number of units for the tunnel networks and the number of layers for the initial per- ceptrons. With regard to real problems of recognition of numbers and images, we ob- serve that tunnel networks achieve better performance, providing a better regularized model and using fewer parameters com- pared to backbone networks. Also, novice perceptrons showed comparable or better performance. Compared to tunnel networks, 82 Моделі та методи машинного навчання novice perceptrons appear to grow larger and shrink less. By setting the learning rate in descending order, it is observed that dif- ferent layers grow at different rates and are used in different ways. Combined with reg- ularization, this allows tunnel networks to keep some of the unused upper layers lin- ear, thus effectively removing them from the network at the end. Deep learning is an AI function that mimics the workings of the human brain in such a way that it processes data and cre- ates patterns for use in decision making [35]. Cognition is a fundamental feature of natural intelligence. Sensory cognitive net- works provide new technological support to dramatically increase the quantity and qual- ity of information that can be collected and transmitted in complex adaptive systems. Their application can significantly increase the level of intelligence in the design and implementation of the system to the levels at which the effects of cognition will begin to manifest themselves. Cognitive abilities can be thought of as a shared sensory net- work. The detection system learns to detect changes not only in signal levels, but also in the shape and parameters of the sensor sig- nal, which is a more difficult task. The ar- chitecture can significantly reduce resource consumption without sacrificing change detection performance. Experiments prove that a neural network-based change detec- tion system is feasible for developing sensor network applications and can be success- fully implemented on available technology platforms. Designing cognitive radars has sev- eral stages. At the first stage we develop user requirements. The second is the for- malization of user requirements. Next, we develop a model of radar operation, check the receipt of the declared quality charac- teristics of the radar. In the fourth stage, we conduct in-depth training of the gener- ated neural network with an inverse loop, for which the radar is calibrated. Based on the calibration results, the development of the developing cognitive radar system is adjusted. Consider in more detail the calibration of 3D-Imaging radar, devel- oped and manufactured in SPC «Quantor» on the example of obtaining a 3D image of the internal structure of the multilayer material. The possibility calibration of is studied in the exploring of material proper- ties to the example of multilayer structure, depending on the distance between the sample and the antenna using an absorber. The results of preliminary studies indicate the possibility of measuring the thickness of the material. On the calibration, a small metal plate and several measurement cy- cles for averaging the noise were used. It is shown that the accuracy of measurements is influenced by the width of the radiation pattern, the number of measurement cycles at one point, the accuracy of positioning and moving the head during the measure- ments, and the time interval between the calibrations. We have developed algorithms and have obtained the required accuracy. We will try to test the radar system, having previously calibrated it. Before carrying out the measurements, we set: 1. The horn and the sample close the absorber to reduce the refl ections; 2. We measure the signal without a sample; 3. We place the sample (5-10) mm and begin to measure; 4. Very carefully, a thin conductive fi lm is pasted from above and measurements are taken; 5. Very gently fl ip back with a conduct- ing medium and measure. Fig.3. Implementation of 3D scanning of small objects by cognitive FMCW 3D-Imaging Radar terahertz range. 83 Моделі та методи машинного навчання Fig.4. Functional diagram of 3D Imaging FMCW Terahertz Radar. If all done carefully, there should be a shift of even a fraction of a millimeter. Scan must be disabled. We will make a point of 50 measurements. Fig.5. Propagation of radar radiation in a multilayer material. 1. Diff erent materials have a diff erent permittivity and diff erent velocity of phase of electromagnetic wave. This gives that real thickness between upper and lower plane of samples is equivalent to virtual thickness be- tween real upper and virtual lower plane in air. We can estimate equivalent virtual thick- ness between metal planes in air and then cor- rect result for real material. 2. In real materials we have a multiple refl ection. This gives several spectral lines for one thickness of the sample. 3. Refl ections from virtual metal planes do not fully correspond to refl ections from real metal planes during calibration. There are numerous errors of discrepancy between virtual planes and the nearest cali- bration levels. This gives multiple errors in the spectral lines and creates some diffi cul- ties in estimating the thickness. 4. Some calibration levels must be pre- sented lower than baseline to estimate posi- tions of virtual metal planes. 5. We try to fi x existing mathematic problems and to get a mathematical tool for universal measurement device. 6. We check the additional measure- ment confi guration. For calibration, we use a special sample with a higher accuracy – Plexiglas. As a result of the measurement cycle, a frequency dependence of the attenuation in the microwave channel D (f) =Uref (f)/Uinc (f) is obtained. Unknown parameters of the dielec- tric structure are determined by procedure of global minimization of discrepancy between the measured attenuation in channel D(f) and one calculated theoretically Dth(f, p) f th fDfDF 2,pp . Here Dth(f, p) is defi ned according to the formula 2 233 10 )1)(1( cc c th VVkVkVk VVkkD , and 0 3( ),.., ( )k f k f are complex coeffi cients, which are determined experimentally using reference samples and describe properties of the microwave channel; f is the frequency of sounding waves; VC (f) is the complex refl ec- tion coeffi cient (CRC) of the reference arm 3; V (f,p) is a theoretically calculated CRC of the dielectric structure, which depends on a vector of the structure parameters p (thick- ness of layers and electrical parameters of materials). We consider that in free space extends a plane electromagnetic wave and normally incident on the infi nite (M-1)-layer medium with fl at boundaries. The CRC V (f, p) is relat- ed of the CRC of the structure in free space VS (f, p) through the scattering matrix of the an- tenna S, which is determined experimentally: S S VS VS SV 22 21 11 1 . 84 Моделі та методи машинного навчання The CRC of the structure in free space depends on the thickness and electrophysical parameters of structure layers: VS=VS(f,h1,..,hM-1,ε1,..,εM,tgδ1,...,tgδM), where hm, εm, tgδm is thickness, permittivity and loss tangent of m-th layer. The CRC of the plane wave from dielectric plane-lay- ered medium VS(f,p) is determined by the known formulas: 10 10 YW YW VS , , )1(exp)1(exp )1(exp)1(exp 1 1 mmmm mmmm mm qYqW qWqYWY ,MM WY 0/mmW ; )sin1(22 2 0mmm hfjq ; )tg1(0 mmm j , where ε0, is permittivity and μ0 is the perme- ability of free space. During the setup process, we do not need to change the distance between the sig- nal and the base line, but we need to will move the device and perform a calibration at the center of each step. This calibration pro- cess is simpler and can be performed in auto- matic mode without an additional table with a micrometer. Сonclusions This article provides a summary of the development of modern radar systems. It is shown that with the development of Artificial Intelligence technologies, mod- ern radars use deep learning neural net- works, as a result, radars have become cognitive. There is no alternative to satisfy the consumer in terms of quality indicators using old technologies. Scientific, techno- logical, information base is ready for such challenges. The need for modern radars is also huge: medicine, security, defense, the Internet of things, and others. Scenarios are becoming more complex and require creative solutions. Cognitive radar is one potential solution that has long been dis- cussed in the literature. It has been shown that cognitive ra- dars can coexist in a congested spectrum, including with random and intentional in- terference, and be invisible. 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Smith, “Fully adaptive radar for track update control,” in Proc. IEEE Radar Conf., 2018, pp. 0400–0404. 37. L. Ubeda-Medina and J. Grajal, “Multiple target tracking in the fully adaptive radar framework,” in Proc. IEEE Statist. Signal Process. Workshop, 2016, pp. 1–5. 38. R. Rovol. 49, no. 2, pp. 915–931, Apr. 2013. Received: 05.02.2022 About the authors: Mykola Коsovets Leading Constructor, Number of scientifi c publications in Ukrainian publications -56 Number of scientifi c publications in foreign publications -17 Index Girsh - 5 https://orcid.org/0000-0001- 8443-7805 Scopus Author ID: 5644007500 Lilia Tovstenko Leading Software Engineer Number of scientifi c publications in Ukrainian publications -24 Number of scientifi c publications in foreign lands -8 Index Girsh -7 https://orcid.org/0000-0002-3348-6065 Scopus Author ID: 56439972800 Place of work: Mykola Коsovets SPE “Quantor”, Chief 03057, c. Kyiv-57, str. Е. Potye, 8-А Ph.: (380)66-2554143 E-mail: quantor.nik@gmail.com Lilia Tovstenko Institute of Cybernetics of Glouchkov National Academy of the National Academy Sciences Ukraine 03187, Kyiv-187, Academician Glouchkov Avenue, 40. Ph.: (380)67-7774010 E-mail: 115lili@incyb.kiev.ua