Radio Receiver Research Articles

OPTIMIZATION OF RADIO SYSTEM STRUCTURES FOR DIRECTION FINDING OF SIGNAL SOURCES WITH COMPLETELY KNOWN PARAMETERS

Context. Direction finders are critical components of radar and radio navigation systems, particularly when installed onboard UAVs. The increasing use of unmanned systems has heightened the need for precise direction finding and wide-angle unambiguous measurements. The primary challenge is to strike a balance between achieving high accuracy and maintaining a broad range of unambiguous measurement angles. Objective. To simultaneously enhance direction finding accuracy and expand the range of unambiguous measurement angles through the statistical synthesis of functionally deterministic signal processing methods in multichannel direction finders. Method. The approach is grounded in the statistical theory of optimization for radio remote sensing and radar systems. For the specific type of signals considered in this study, represented by functional-deterministic models, the likelihood function is constructed, and its maxima are determined for various configurations of multi-antenna direction finders. The statistical synthesis results are validated through simulation and in-situ experiments. Results. Theoretical analysis and simulation modeling confirm that in dual-antenna direction finders, there is a trade-off between high resolution and the range of unambiguous direction finding angles. An improved signal processing method is developed for a four-antenna direction finder, utilizing a pair of high-gain and a pair of low-gain antennas. To achieve the maximum possible bearing accuracy within the range of unambiguous direction finder measurements, a new signal processing method is synthesized for a sixelement radio receiver, combining the processing of signals in two amplitude direction finders and one phase direction finder. Conclusions. The proposed approach achieves an optimal balance between resolution and angle range, making it particularly suitable for onboard systems of unmanned aerial vehicles. Simulation results confirm the effectiveness of the proposed method, highlighting its potential for implementation in modern radio systems.

Theoretical Analysis and Design Implementation of FM Broadcast Receiving System based on SDR

ADALM Pluto is a software-defined radio product. Based on theoretical analysis, this paper designs a Frequency Modulation (FM) broadcast receiving system using ADALM Pluto as a wireless receiver on the Simulink platform. The simulation results show that the theoretical analysis is correct and the parameter settings are reasonable, and the Software-Defined Radio (SDR) has the characteristics of high performance, high ease of use, and low cost.

Low-cost multi-sensing fire-fighting robot with obstacle avoidance mechanism

Robots are mostly optimized for tasks that require strength exceeding that of humans or for operations in hazardous environments. The fire-fighting robot developed has multiple sensing capabilities with obstacle avoidance mechanisms and is divided into two units: the robot and the static unit. The robot is equipped with three flame sensors to detect flames (infrared radiation) in three directions, an ultrasonic sensor to avoid obstacles, a wireless receiver to receive data from the static unit, a magnetometer giving the robot a sense of direction, and a unit of Arduino Mega microcontroller serving as the central controlling platform. The static unit has four flame sensors and a transmitter that transmits signals to the robot unit, which an Arduino Uno directly controls. A prototype was developed, which helps prevent the escalation of fires in the home as it can detect, navigate and extinguish flames while avoiding obstacles autonomously.

Расчет электромагнитной совместимости радиооборудования пункта управления беспилотной авиационной системы со станционарными наземными радиоэлектронными средствами

An analysis procedure of electromagnetic compatibility between radio equipment of a com-mand and control point (CP) of unmanned aircraft (UA) carrying a radio transmitter (RT) and a radio receiver (RR) and stationary land radio electronic equipment (REE) stations containing radio transmitters and/or radio receivers and surrounding the CCP is considered. The procedure involves analysis of the scenarios where emissions produced by the surrounding transmitters may have an effect on the quality of the signal received by the CCP receiver and where the emission produced by the CCP transmitter may have effect on the quality of signals received by the recei¬vers surrounding the CCP. It assumed that frequency-hopping spread spectrum signals are applied in both downlink and uplink. To assess the interference effect from emissions of the surrounding transmitters on the quality of the signal received by the CCP receiver the protection ratio is used. To assess the interference effect from emissions of the CCP transmitter on the quality of the signal received by the surrounding receivers the receiver desensitization is used.

The activities of public service media in new media and its funding

With the development of new technologies, the so-called new media are gaining importance and popularity in society. This leads to a strengthening of the presence of public media in the field of new media. In this context, the author examines how they are moving from a long-term licence model aimed at charging for the ownership of the radio or television receiver to generating income for activities in the field of new media. One of the options is to generate income through advertising, sponsorship or product placement in the online space, another option is to change the fee model and shift to tax, respectively charging natural and legalpersons regardless of the ownership of the receiver. In this context, the author analyses the situation in three Central European countries (Czechia, Slovakia and Austria) that are currently reforming the funding of public service media. In the research, the author focuses on the activity of public media in the online space and how they are changing the current funding model in this regard. The research methods used are mainly analysis of legislative and budgetary documents. The author concludes that public service media tend to move towards new funding models that are either more universal or secure funding from the state budget. National legislation regulating public service media is also being adapted to the new activities of public service media in new media, with measures to ensure the independence of online broadcasting.

Study of Radio Reconnaissance Receivers Designed on the Basis of Solid-state Filters

Radio intelligence systems are vital technological resources that contribute significantly to contemporary security, defense, and intelligence efforts. They enable the monitoring of adversaries' communication signals, the decryption of encrypted information, and the acquisition of strategic advantages. These systems are essential for military operations, counter-terrorism efforts, national security, and strategic planning. As radio intelligence continues to evolve, it is anticipated that more effective and multifunctional systems will emerge in the future.In modern electronic warfare, radio reconnaissance stations are essential for effective signal detection, classification, and geolocation of enemy communication and radar signals. Current advancements in radio reconnaissance technology focus on enhancing measurement accuracy and reliability, crucial for precise threat identification and situational awareness. Key improvements include implementing high-resolution digital signal processing algorithms, advanced filtering techniques, and real-time data fusion to increase detection precision across complex environments. Furthermore, there is a strategic emphasis on reducing the physical dimensions and weight of these stations to improve mobility and operational efficiency in diverse field conditions. Innovations in miniaturized components, lightweight materials, and compact antenna arrays are central to these design objectives, facilitating deployment in both manned and unmanned platforms. This approach not only optimizes the performance of reconnaissance stations but also broadens their applicability across various operational scenarios, making them integral to modern defense systems. In the article, the application of solid-state filters in the spectrum analyzers of radio reconnaissance receivers was considered in order to increase the measurement accuracy and reliability of radio reconnaissance stations, and to reduce their size and weight. In the article, the modeling of load-connected filter structures was conducted to calculate quasi-statistical potential diagrams, which allows for the optimization of their parameters and reduces the design time of devices based on these filters. The research work was carried out in military unit No. N.

Switched preselector of a multichannel receiver

The development of wideband radio receivers is an important technical task, and its solution is being addressed by numerous enterprises and researchers. Among the well-known enterprises-developers of professional radio-receiving devices it is necessary to mention ANII "Vector" (St. Petersburg), JSC SPE "Istok" (Fryazino), JSC "Salyut" (Nizhny Novgorod), Rostov Research Institute of Radio Communications, Voronezh Research Institute of Radio Communications, "Scard-Elektronics" (Kursk), Omsk NIIP. There are even more manufacturers of broadband radio receiving devices abroad, but it is not appropriate to list them here. Modeling and experimental study of a preselector for a multichannel receiver is carried out. The functional scheme of the preselector, the circuit diagram of one channel out of four, the model of this filter in the program CST Studio Suite and the amplitude-frequency characteristics are given. The structural scheme of the experiment and amplitude-frequency characteristics in the near and far zones are presented. The achievement of the following parameters is shown: Bandwidth from 3.5 to 4.0 GHz; Bandstop from 4.5 to 18.0 GHz; Transmission coefficient greater than 10 dB in the passband; Gain at frequencies 3f0 and 5f0 not less than 60 dB; Wave impedance of 50 ohms. The studied preselector has a wide frequency and dynamic range, high selectivity, so it allows to realize a modern receiver. The basis of the preselector consists of four bandpass filters on counter rods, on the air-strip transmission line. Each of the filters contains 11 resonators. To suppress false pass-bands, the preselector contains a low-pass filter on microstrip transmission lines. To obtain the required transmission coefficient, the preselector contains an amplifier, and to reduce the diversity of channels - a corrector of the amplitude-frequency response.

Assessment of potential electronic warfare capabilities to suppress FPV-type UAV radio control and data transmission receivers

The modern stage of world aviation development is characterized by the creation of complexes with unmanned aerial vehicles (UAVs) of various functional purposes, their massive use and rapid improvement with continuous expansion of their nomenclature and methods of application. The rapid development of unmanned aerial vehicle (UAV) systems is due to their potential merits and advantages, primarily in terms of efficiency and cost, both in comparison with manned aircraft systems and other types of weapons and military equipment. Combat application of UAVs in the course of local wars and armed conflicts and its development trends show that the leading and determining role in the effective use of modern and advanced UAVs is played by radio-electronic systems that ensure the solution of the following tasks: communication, navigation, reconnaissance, guidance and control of onboard weapons. A malfunction of onboard radio-electronic systems significantly reduces the effectiveness of their use. Given this, a significant contribution to improving the effectiveness of the fight against UAVs can be achieved by utilizing the capabilities of electronic warfare (EW). The main peculiarities of technical development of UAVs are constant improvement of their tactical and technical characteristics and interference resistance to the impact of electronic warfare (EW), developed according to simplified schematic solutions. The aim of work to evaluate the main methods of electronic countermeasures of FPV-type UAV control and data transmission radio receivers. The main methods of countermeasures against FPV-type UAVs for protection of personnel and vulnerable elements of critical infrastructure of industrial facilities were evaluated. The article contains theoretical calculations and recommendations on the composition and requirements for modern UAV countermeasures.

A data compression algorithm with the improved SRLE for high-throughput neural signal acquisition device.

Multi-channel acquisition systems of brain neural signals can provide a powerful tool with a wide range of information for the clinical application of brain computer interfaces. High-throughput implantable systems are limited by size and power consumption, posing challenges to system design. To acquire more comprehensive neural signals and wirelessly transmit high-throughput brain neural signals, a FPGA-based acquisition system for multi-channel brain nerve signals has been developed. And the Bluetooth transmission with low-power technology are utilized. To wirelessly transmit large amount of data with limited Bluetooth bandwidth and improve the accuracy of neural signal decoding, an improved sharing run length encoding (SRLE) is proposed to compress the spike data of brain neural signal to improve the transmission efficiency of the system. The functional prototype has been developed, which consists of multi-channel data acquisition chips, FPGA main control module with the improved SRLE, a wireless data transmitter, a wireless data receiver and an upper computer. And the developed functional prototype was tested for spike detection of brain neural signal by animal experiments. From the animal experiments, it shows that the system can successfully collect and transmit brain nerve signals. And the improved SRLE algorithm has an excellent compression effect with the average compression rate of 5.94%, compared to the double run-length encoding, the FDR encoding, and the traditional run-length encoding. The developed system, incorporating the improved SRLE algorithm, is capable of wirelessly capturing spike signals with 1024 channels, thereby realizing the implantable systems of High-throughput brain neural signals.

Expertise hubs and the credibility challenge for open-source intelligence: insights from usage patterns of a web-controlled radio receiver and related Twitter traffic in the Ukraine war

ABSTRACT This article analyses how new open-source intelligence methods democratise and complement traditional signals intelligence while bundling dispersed expertise required to ensure the quality of data and the confidence we can have in analysis. It examines the case of OSINT activity on web-controlled radio receivers since 2022 about Russian military communications in Ukraine. It uses network analysis to show the extent of information leakage, analysis and collaboration by various actors that perform different tasks of crowdsourcing, vetting and interpreting information to make it actionable. We advance the field in knowledge of open-source intelligence gathering, dissemination and use.

Devising a method for integrated dataset formation and selecting a model for recognizing the technical condition of unmanned aerial vehicle

The object of this study is the process of forming a training dataset for diagnosing the technical condition of unmanned aerial vehicles (UAVs) using machine-learning algorithms. UAV flights are extremely important for various aspects of troop deployment. Combat UAV flights are performed under the influence of negative factors that cause flight special cases (FSC), which hinder the execution of combat missions, lead to mission failures, and result in the aircraft damage or loss. The available capabilities of autopilots are not enough for control under complex conditions, and in certain situations, the human operator cannot timely recognize a flight special case, including evaluation of the destructive impact of enemy’s electronic warfare systems on communication channels and operation of UAV. Therefore, the urgent issue is the intellectualization of onboard control systems, particularly towards recognizing the current technical state of UAV using artificial intelligence methods. To design such systems, labeled datasets are required. The procedure for forming datasets that consider the specificity of UAV construction and their combat use under adversarial conditions is not defined, necessitating the development of an appropriate method. Based on the well-known CRISP-DM methodology, a method for dataset formation has been proposed for subsequent use in artificial intelligence systems that use various machine-learning methods. This method differs from existing ones by considering the specificity of combat mission execution under adversarial conditions, which allowed for an 8.0 % increase in the accuracy of recognizing special cases in UAV flights by the onboard system. It also enabled timely detection of electronic warfare impacts on UAV and evaluation of the effectiveness of radio signal receivers jamming

Optimization Analysis of Low-Noise Amplifier

This paper mainly analyzes the important component of a wireless receiver – low-noise amplifiers (LNA). Low-noise amplifiers can reduce the effect of noise on the received signal and amplify signals. For the better development of wireless communication technology, remote control, and other related fields, it is necessary to optimize the design of low-noise amplifiers, so that low-noise operational amplifiers can finally obtain high gain, low noise figure, and other advantages. This paper analyzes the optimization design of LNA in the field of Global Navigation Satellite Systems (GNSS). This paper analyzes a low-noise amplifier design with the operation of concurrent dual-band for GNSS receivers with a single channel. The optimized design of a low-noise amplifier in this field uses a low-cost 0.18µm CMOS tube and adds load capacitances and a feedforward path to reduce the noise figure (NF) of the system. Noise figures in 1.2 GHz and 1.57 GHz bands are reduced by about 0.9 dB. In addition, the high gain, high linearity, and other excellent properties are shown in 1.2 GHz and 1.57GHz. In the application of 5G/6G network technology, the optimized design of Gallium Arsenide (GaAs) PHEMT technology with a gate length of 0.3µmm and inductively degraded common source topology phase structure is adopted. From this optimization, the noise figure is optimized to 1.3-1.4, and the gain of the system is 20-22 dB. At the same time, good linearity is also shown. Then, the prospects of semiconductor materials such as Gallium Nitride (GaN) and Indium Phosphide (InP), which have the advantages of high electron mobility and low-cost design, in optimizing low noise operational amplifiers. To a certain extent, the in-depth study of the optimal design of LNA can improve the technical level of wireless communication, aerospace, and other fields.

Stand for experimental evaluation of suppression of radio receiver of multifunctional radar by electronic warfare equipment

Problem statement. The article considers the problem of assessing the effectiveness of electronic suppression of a multifunctional radar survey receiver by electronic warfare equipment, when it is not possible to use a radar with the necessary signal-code structures of probing signals as an object of suppression during full-scale tests of electronic warfare equipment. The solution to this problem arises when, under conditions of a real radar conflict, it is necessary to perform an operational assessment of the possibility of electronic suppression of a radar that uses signal-code structures of probing signals, the counteraction to which has not been previously assessed. Objective. To develop a test bench for assessing the effectiveness of electronic suppression of a multifunctional radar survey receiver, in which the receiver operates under conditions of suppression by interference generated by real electronic warfare equipment. The test bench should ensure operational change of signal-code structures of probing signals and formation of a digital copy of the survey receiver, consistent with the structure of probing signals. Results. A setup has been developed and implemented in which a probing radar signal is created based on an analytical description of the signal-code structure of a radio signal using a vector generator. This signal description is used to implement a digital copy of the multifunctional locator's surveillance radio receiver. Based on the probing signal, the real electronic warfare equipment generates an interference signal, which, together with a signal simulating the reflected signal, is sent to the digital copy of the surveillance receiver. The suppression efficiency is assessed by analyzing the output signals of the surveillance receiver. The setup implements a circuit that allows setting a specified interference/signal ratio. Practical significance. The setup allows assessing the effectiveness of interference generated by electronic warfare equipment when it is impossible to use radars with the required signal-code structures of probing signals during its testing, or when there is a need to promptly assess the possibility of electronic suppression of an object that uses signal-code structures of probing signals, the counteraction to which has not been previously assessed.

Stretchable wireless optoelectronic synergistic patches for effective wound healing

Physiotherapies play a crucial role in noninvasive tissue engineering for wound healing. However, challenges such as the implementation of complex interventions and unsatisfactory treatment outcomes impede widespread application. Here, we proposed a stretchable and wirelessly-powered optoelectronic synergistic patch with a dual-layer serpentine wireless receiver circuit to drive the optoelectronic modulation component. Optimized structure and impedance matching enable the patch to seamlessly attach to irregular skin surfaces and operate robustly over a 30% tensile strain range. Based on Sprague-Dawley rat wound model. The wound closure rate of the optoelectronic synergistic group significantly outperformed both monointervention and blank control groups. Mechanistically, optoelectronic synergistic intervention enhances the secretion of vascular endothelial marker proteins and growth factors, and stabilizes mitochondrial function during oxidative stress. Overall, the scalable amalgamation of flexible electronics, wireless transmission, and synergistic interventions promise to improve wound care.

Analysis of NR and LTE Target Signal Structure Based on Neural Network Approach and Deep Learning Methods

Purpose: the rapid development and consolidation of broadband wireless access networks of the fourth 4G LTE and fifth 5G NR generations determine the need to find ways to reuse frequencies. A well-known solution to this problem is the concept of cognitive radio. The use of artificial intelligence in radio networks in general and the use of a neural network approach with deep learning for recognizing signals of LTE and NR standards in particular have serious potential for the practical implementation of frequency resource reuse according to the concept of cognitive development. The aim of the work: is to analyze models, methods and algorithms that allow recognizing signals of the NR and LTE standards based on recording samples of radio signals obtained using pre-recorded NR and LTE signals in MatLab software. In this paper, the procedures for scanning and recognizing sections of the spectrum are considered. The operations of training a semantic segmentation network for the identification of these signals in a broadband spectrogram and the use of a trained network for subsequent spectrum sensing and recognition of signals of the NR and LTE standards are investigated. Methods: the method used to test the concept of cognitive radio is spectrum sensing, which results in information about the occupancy of frequency bands in a given location by primary users, and the identification of spectrum sections available for use by secondary users without interfering with the work of primary users in real time. The novelty of the work is the use of a neural network approach in the analysis of the target NR and LTE signal. Results: the model, trained on the basis of a neural network approach and deep learning methods, is able to distinguish between signals of the NR and LTE standards. Theoretical / Practical relevance: the software implementation of spectral sensing is implemented using an extension package in the MatLab environment and allows for experimental testing of a cognitive radio receiver when performing procedures for analyzing the structure of the target signal of the NR and LTE standards based on a neural network approach and deep learning methods.

Temporally Resolved Type III Solar Radio Bursts in the Frequency Range 3–13 MHz

Radio observations from space allow to characterize solar radio bursts below the ionospheric cutoff, which are otherwise inaccessible, but suffer from low, insufficient temporal resolution. In this Letter we present novel, high-temporal resolution observations of type III solar radio bursts in the range 3–13 MHz. A dedicated configuration of the Radio and Plasma Waves (RPW) High Frequency Receiver (HFR) on the Solar Orbiter mission, allowing for a temporal resolution as high as ∼0.07 s (up to 2 orders of magnitude better than any other spacecraft measurements), provides for the very first time resolved measurements of the typical decay time values in this frequency range. The comparison of data with different time resolutions and acquired at different radial distances indicates that discrepancies with decay time values provided in previous studies are only due to the insufficient time resolution not allowing to accurately characterize decay times in this frequency range. The statistical analysis on a large sample of ∼500 type III radio bursts shows a power low decay time trend with a spectral index of −0.75 ± 0.03 when the median values for each frequency are considered. When these results are combined with previous observations, referring to frequencies outside the considered range, a spectral index of −1.00 ± 0.01 is found in the range ∼0.05–300 MHz, compatible with the presence of radio-wave scattering between 1 and 100 R ☉.

An Energy-Efficient Wireless Power Receiver With One-Step Adiabatic-Bipolar-Supply Generating for Implantable Electrical Stimulation Applications.

This paper presents an energy-efficient wireless power receiver for implantable electrical stimulation applications, which can achieve one-step adiabatic bipolar-supply that is generated by a hybrid single-stage dual-output regulating (SSDOR) rectifiers. The structure using only four switches overcomes the disadvantages that the two output voltage values in the traditional dual-output rectifiers are close to each other. A constant-current (CC) controlled adiabatic dynamic voltage scaling (DVS) technique is proposed to minimize the voltage headroom of the stimulating drivers and improve the stimulation efficiency significantly. In addition, the receiver adopts only one general constant on-time (COT) low-frequency control to adjust the stimulation current, reducing both the power consumption and the complexity of the control circuits. The proposed receiver has been fabricated in a 0.18 μm BCD process with ±6 V voltage compliance and 2.5 mA maximum stimulating current. With a current range from ±1.5 mA to ±2.5 mA, the measured maximum average headroom voltage is only 80 mV and the peak total efficiency of the receiver is 85.6 %. The functionalities of the proposed receiver have been successfully verified through in vitro experiments.

An Adaptive On-Off-Delay Compensation Scheme Based on Dead-Time and Rectified-Current Sampling for Ampere-Current-Level Series-Series Wireless Power Receivers

An Adaptive On-Off-Delay Compensation Scheme Based on Dead-Time and Rectified-Current Sampling for Ampere-Current-Level Series-Series Wireless Power Receivers

Differential Delay of Ordinary and Extraordinary Modes of Transionospheric Radio Waves

AbstractThe terrestrial ionosphere is a birefringent medium that allows radio waves to propagate in two modes: the ordinary (O‐mode) and the extraordinary (X‐mode). A difference in the index of refraction of the two modes results in differential delay (mode delay) between the O‐ and X‐modes of radio waves propagating through the ionosphere. Mode delays of transionospheric high frequency radio waves are determined using the Radio Receiver Instrument (RRI) onboard the Enhanced Polar Outflow Probe (e‐POP) on the CASSIOPE/Swarm‐E satellite. Experiments between RRI and the SuperDARN radar at Saskatoon, Canada show large variabilities in mode delays. The mode delays are nearly constant in some experiments but other experiments have large variations. The mode delay observations could not be explained by the distance between the e‐POP satellite and the radar, the foF2 values along the satellite track, nor whether the satellite track was across or along a SuperDARN radar beam. A combination of RRI observations and ray‐trace modeling are used to investigate the mode delay of transionospheric radio waves.

Narrow-Band, Band-Stop Filter Designs with Different Numbers of L-Resonators

Filters have an important place in RF and microwave engineering. Filtering certain frequencies is one of the most basic needs in receiver and transmitter systems. Today, microstrip filters are used in many areas of microwave engineering such as radar systems, cellular communications, test/measurement systems, wireless modems, radio and television receivers, and remote control systems. In these filter structures; high performance, low loss, small size, and low-cost requirements are sought. In this study, narrow-band, band-stop filter designs with different numbers of L-resonators at a frequency of 2.45 Hz were realized. The main goal of this study is to design filters with higher performance, lower return loss, and more compact and useful sizes. Thanks to these filter designs, undesirable signals are filtered and targeted signals are transmitted appropriately.