Methods and algorithms of angular estimation with super-resolution for aviation airborne radar systems

2021 ◽  
Author(s):  
V.S. Verba ◽  
V.I. Merkulov ◽  
V.S. Chernov
Keyword(s):  
Antenna Arrays ◽  
Super Resolution ◽  
Radar System ◽  
Total Output ◽  
Technical Literature ◽  
Advantages And Disadvantages ◽  
Radar Systems ◽  
Ring Antenna ◽  
Angular Coordinates ◽  
Four Quadrant

In the practical application of aircraft, there may be situations when it is not possible to resolve radar target signals in the measurement channels of range, speed and angular coordinates in the on-board radar system. In these situations, it is advisable to use angular estimation procedures with super-resolution in the onboard radar system. Various methods and algorithms of angular estimation with super-resolution are known, each of which has its own advantages and disadvantages. At the same time, there is no information in the available scientific and technical literature about the algorithms of angular estimation with super-resolution used in the onboard radar system, knowledge of which is necessary when designing promising onboard radar systems. The article systematizes and analyzes the methods and algorithms of angular estimation with super-resolution. The classification of methods of angular estimation with superresolution is given. The generalized information about the known one-dimensional and twodimensional methods and algorithms of angular estimation is given. The algorithms proposed for use in flat antenna arrays, concentric ring antenna arrays, ring antenna arrays, round four-quadrant antenna arrays, flat antenna arrays with a total output signal are considered. It is noted that the features of the construction of radar homing heads include a reduction in the total number of information processing channels achieved by combining antenna elements into sublattices, the output signals of which are used to estimate the angular coordinates of radiation sources. The specificity of such antenna arrays is that the antenna sublattices have radiation patterns that are narrower than those of weakly directed antenna elements. In addition, the distance between the antenna modules can significantly exceed the distance between the antenna elements in a conventional antenna array and at the same time significantly exceed the wavelength size. To determine the possibilities of applying in practice the algorithms of angular two-dimensional estimation with super-resolution considered in the article in the onboard radar system, it is necessary to conduct special studies.

scholarly journals Radar system with dedicated planar traveling wave antennas for elderly people monitoring

2020 ◽  
Vol 18 ◽  
pp. 97-110
Author(s):  
Sassan Schäfer ◽  
Simon Müller ◽  
Daniel Schmiech ◽  
Andreas R. Diewald
Keyword(s):  
Elderly People ◽  
Antenna Arrays ◽  
Traveling Wave ◽  
Radar System ◽  
Propagation Path ◽  
Design Parameters ◽  
Microstrip Technology ◽  
Actual Object ◽  
Radar Systems ◽  
24 Ghz

Abstract. Radar systems for contactless vital sign monitoring are well known and an actual object of research. These radar-based sensors could be used for monitoring of elderly people in their homes but also for detecting the activity of prisoners and to control electrical devices (light, audio, etc.) in smart living environments. Mostly these sensors are foreseen to be mounted on the ceiling in the middle of a room. In retirement homes the rooms are mostly rectangular and of standardized size. Furniture like beds and seating are found at the borders or the corners of the room. As the propagation path from the center of the room ceiling to the borders and corners of a room is 1.4 and 1.7 time longer the power reflected by people located there is 6 or even 10 dB lower than if located in the center of the room. Furthermore classical antennas in microstrip technology are strengthening radiation in broadside direction. Radar systems with only one single planar antenna must be mounted horizontally aligned when measuring in all directions. Thus an antenna pattern which is increasing radiation in the room corners and borders for compensation of free space loss is needed. In this contribution a specification of classical room sizes in retirement homes are given. A method for shaping the antenna gain in the E-plane by an one-dimensional series-fed traveling wave patch array and in the H-plane by an antenna feeding network for improvement of people detection in the room borders and corners is presented for a 24 GHz digital beamforming (DBF) radar system. The feeding network is a parallel-fed power divider for microstrip patch antennas at 24 GHz. Both approaches are explained in theory. The design parameters and the layout of the antennas are given. The simulation of the antenna arrays are executed with CST MWS. Simulations and measurements of the proposed antennas are compared to each other. Both antennas are used for the transmit and the receive channel either. The sensor topology of the radar system is explained. Furthermore the measurement results of the protoype are presented and discussed.

Methods of counteraction to means of electronic reconnaissance of the enemy during the operation of pulse-Doppler onboard radars of fighters for radiation

2021 ◽  
Author(s):  
A.V. Bogdanov ◽  
D.V. Zakomoldin ◽  
I.V. Kochetov ◽  
S.I. Akimov
Keyword(s):  
Radiation Power ◽  
Group Actions ◽  
Radar System ◽  
Radar Signal ◽  
Airborne Radar ◽  
Energy Potential ◽  
Advantages And Disadvantages ◽  
Radar Systems ◽  
Pulse Doppler ◽  
Technical Measures

The article proposes methods of counteraction to the enemy's electronic reconnaissance means, both for a duel situation and for group actions of fighters, analyzes their advantages and disadvantages, identifies limitations on their use. The physical meaning of these methods is to ensure the secrecy of the operation of on-board radar systems for radiation, due to the variation in the energy potential of the station, in particular, the time of coherent energy accumulation in narrow-band Doppler filters when receiving signals reflected from air targets and the radiation power of the transmitter of the on-board radar system when forming sounding radar signal packs. In the article, along with the methods of ensuring the secrecy of the operation of onboard radar systems of fighters, which make it possible to carry out technical measures only after radar contact with an air target equipped with electronic reconnaissance means, which leads to a decrease in their effectiveness, methods for controlling the secrecy of the operation of onboard radar systems of fighters are additionally given, allowing to provide stealth with a given probability in the dynamics of the approach of a fighter with its emitting airborne radar system with an air target, equipped with electronic reconnaissance means. In addition, it should be noted the method of managing the energy secrecy of airborne radar systems during group actions of fighters, within the framework of the development of which the possibility of summing up the powers emitted by the transmitters of the onboard radar systems of fighters when they work together for radiation in the position of conducting electronic reconnaissance is taken into account. Implementation of the developed methods will allow: to increase the survivability of fighters, and to an increase in this indicator, both the ensured secrecy of the operation of onboard radar systems of fighters for radiation and the implementation of the multi-position principle of building radar systems, given in the method of stealth control of the onboard radar system of fighters during group actions of fighters. to expand the combat capabilities of fighters, due to the fact that the covert operation of the onboard radar systems of fighters for radiation excludes the possibility of reconnaissance of the parameters of the sounding signal and, as a result, the possibility of setting active interference is excluded.

Grammatical Difficulties of Automatic Translation of Scientific and Technical Literature

2019 ◽  
Vol 26 (27) ◽  
pp. 134-141
Author(s):  
Aliona Kolesnichenko ◽  
Natalya Zhmayeva
Keyword(s):  
Key Words ◽  
Technical Literature ◽  
Automatic Translation ◽  
Advantages And Disadvantages ◽  
Grammatical Errors ◽  
Translation Service

The article is devoted to the analysis of grammatical difficulties encountered in the process of automatic translation. The paper discusses the advantages and disadvantages of the SDL Trados automatic translation service. The types of grammatical errors when translating scientific and technical texts in SDL Trados are classified, the ways of overcoming them are outlined. Key words: scientific and technical literature, automatic translation, grammatical difficulties.

METHODS FOR RESTORING WOLVES OF ROLLING PRODUCTION

2020 ◽  
Vol 4 (141) ◽  
pp. 114-122
Author(s):  
DAR’YA LEBEDEVA ◽  
◽  
ANNA KARPUNICHEVA
Keyword(s):  
Thermal Effects ◽  
Machine Building ◽  
Research Purpose ◽  
Technical Literature ◽  
Production Methods ◽  
Advantages And Disadvantages ◽  
Rolling Production ◽  
Machine Parts ◽  
The Stability ◽  
High Degree

Large forces and significant thermal effects are created on the rolls when rolling sheets. The higher the stability of the rolls, the less downtime during their rerolling and higher productivity. (Research purpose) The research purpose is in analyzing the ways of restoring rolls and choose the most appropriate method for restoring these parts. (Materials and methods) The article presents the analysis of the scientific and technical literature on the topic of rolling production, methods for restoring large-sized machine parts of machine-building and metallurgical industries that work in difficult conditions and are subject to a high degree of wear. Authors try to solve the problem by means of comparative and logical analysis based on theoretical and empirical methods of scientific research. (Results and discussion) The article presents two groups of methods for restoring rolled rolls: banding and surfacing the working layer of the roll. Authors have analyzed each method in terms of technology, equipment, and feasibility. The article presents the advantages and disadvantages of the methods under consideration. (Conclusions) The most acceptable way to restore parts with a high degree of wear is surfacing. It is most efficient to apply submerged surfacing using an additional hot additive. Such surfacing, despite some complication of the equipment design, allows to deposit the metal on the roll with low heat input and in most cases in one pass. Surfacing using an additional hot additive allows to increase the productivity of the process by up to 250 percent while reducing the penetration depth by 2-3 times and saving energy by up to 40 percent.

scholarly journals Probabilistic analysis of ambiguities in radar echo direction of arrival from meteors

2020 ◽  
Author(s):  
Daniel Kastinen ◽  
Johan Kero
Keyword(s):  
Bayesian Method ◽  
Direction Of Arrival ◽  
Radar System ◽  
Stable Region ◽  
Radar Signal ◽  
Ambient Atmosphere ◽  
Radar Systems ◽  
Mu Radar ◽  
Meteor Trail ◽  
The Antarctic

Abstract. Meteors and hard targets produce coherent radar echoes. If measured with an interferometric radar system, these echoes can be used to determine the position of the target through finding the Direction Of Arrival (DOA) of the incoming echo onto the radar. If the DOA of meteor trail plasma drifting with the ambient atmosphere is determined, the neutral wind at the observation altitude can be calculated. Specular meteor trail radars have become widespread scientific instruments to study atmospheric dynamics. Meteor head echo measurements also contribute to studies of the atmosphere as the meteoroid input of extraterrestrial material is relevant for a plethora of atmospheric phenomena. Depending on the spatial configuration of radar receiving antennas and their individual gain patterns, there may be an ambiguity problem when determining the DOA of an echo. Radars that are theoretically ambiguity free are known to still have ambiguities that depend on the total radar Signal to Noise Ratio (SNR). In this study we investigate robust methods which are easy to implement to determine the effect of ambiguities on any hard target DOA determination by interferometric radar systems. We apply these methods specifically to simulate four different radar systems measuring meteor head and trail echoes using the multiple signal classification (MUSIC) DOA determination algorithm. The four radar systems are the middle and upper atmosphere (MU) radar in Japan, a generic Jones 2.5λ specular meteor trail radar configuration, the Middle Atmosphere Alomar Radar System (MAARSY) radar in Norway and the The Program of the Antarctic Syowa Mesosphere Stratosphere Troposphere Incoherent Scatter (PANSY) radar in the Antarctic. We also examined a slightly perturbed Jones 2.5λ configuration used as a meteor trail echo receiver for the PANSY radar. All the results are derived from simulations and their purpose is to grant understanding of the behaviour of DOA determination. General results are: there may be a region of SNRs where ambiguities are relevant; Monte Carlo simulation determines this region and if it exists; the MUSIC function peak value is directly correlated with the ambiguous region; a Bayesian method is presented that may be able to analyse echoes from this region; the DOA of echoes with SNRs larger then this region are perfectly determined; the DOA of echoes with SNRs smaller then this region completely fail to be determined; the location of this region is shifted based on the total SNR versus the channel SNR in the direction of the target; asymmetric subgroups can cause ambiguities even for ambiguity free radars. For a DOA located at the zenith, the end of the ambiguous region is located at 17 dB SNR for the MU radar and 3 dB SNR for the PANSY radar. The Jones radars are usually used to measure specular trail echoes far from zenith. The ambiguous region for a DOA at 75.5° elevation and 0° azimuth ends at 12 dB SNR. Using the Bayesian method it may be possible to analyse echoes down to 4 dB SNR for the Jones configuration, given enough data points from the same target. The PANSY meteor trail echo receiver did not deviate significantly from the generic Jones configuration. The MAARSY radar could not resolve arbitrary DOAs sufficiently well to determine a stable region. However, if the DOA search is restricted to 70° elevation or above by assumption, stable DOA determination occurs above 15 dB SNR.

Review on critical technology development of avian radar system

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Weishi Chen ◽  
Yifeng Huang ◽  
Xianfeng Lu ◽  
Jie Zhang
Keyword(s):  
Technology Development ◽  
Time Integration ◽  
Radar System ◽  
Content Type ◽  
Advantages And Disadvantages ◽  
Detection And Tracking ◽  
Critical Technology ◽  
Long Time ◽  
Long Time Integration ◽  
Target Characteristics

Purpose This paper aims to review the critical technology development of avian radar system at airports. Design/methodology/approach After the origin of avian radar technology is discussed, the target characteristics of flying birds are analyzed, including the target echo amplitude, flight speed, flight height, trajectory and micro-Doppler. Four typical airport avian radar systems of Merlin, Accipiter, Robin and CAST are introduced. The performance of different modules such as antenna, target detection and tracking, target recognition and classification, analysis of bird information together determines the detection ability of avian radar. The performances and key technologies of the ubiquitous avian radar are summarized and compared with other systems, and their applications, deployment modes, as well as their advantages and disadvantages are introduced and analyzed. Findings The ubiquitous avian radar achieves the long-time integration of target echoes, which greatly improves detection and classification ability of the targets of birds or drones, even under strong background clutter at airport. In addition, based on the big data of bird situation accumulated by avian radar, the rules of bird activity around the airport can be mined to guide the bird avoidance work. Originality/value This paper presented a novel avian radar system based on ubiquitous digital radar technology. The authors’ experience has confirmed that this system can be effective for airport bird strike prevention and management. In the future, the avian radar system will see continued improvement in both software and hardware, as the system is designed to be easily extensible.

Machine Learning and Deep Learning Techniques for Colocated MIMO Radars: A Tutorial Overview

2021 ◽  
Author(s):  
ALESSANDRO DAVOLI ◽  
Giorgio Guerzoni ◽  
Giorgio Matteo Vitetta
Keyword(s):  
Machine Learning ◽  
Signal Processing ◽  
Deep Learning ◽  
Antenna Arrays ◽  
Research Work ◽  
Radar Signal ◽  
Open Problems ◽  
Technical Problems ◽  
Radar Systems ◽  
Learning Techniques

<p>Radars are expected to become the main sensors in various civilian applications, ranging from health-care monitoring to autonomous driving. Their success is mainly due to the availability of both low cost integrated devices, equipped with compact antenna arrays, and computationally efficient signal processing techniques. An increasingly important role in the field of radar signal processing is played by machine learning and deep learning techniques. Their use has been first taken into consideration in human gesture and motion recognition, and in various healthcare applications. More recently, their exploitation in object detection and localization has been also investigated. The research work accomplished in these areas has raised various technical problems that need to be carefully addressed before adopting the above mentioned techniques in real world radar systems. In this manuscript, a comprehensive overview of the machine learning and deep learning techniques currently being considered for their use in radar systems is provided. Moreover, some relevant open problems and current trends in this research area are analysed. Finally, various numerical results, based on both synthetically generated and experimental datasets, and referring to two different applications are illustrated. These allow readers to assess the efficacy of specific methods and to compare them in terms of accuracy and computational effort.</p>

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