Radar Equipment Research Articles

РАЗРАБОТКА ПРОГРАММЫ ПРОЕКТИРОВАНИЯ СИМУЛЯТОРОВ СОВРЕМЕННЫХ РАДИОТЕХНИЧЕСКИХ СРЕДСТВ ОБЕСПЕЧЕНИЯ ПОЛЕТОВ

The main radio equipment used by aviation specialists are communication, radar and radio navigation systems. Training of students in these areas is a complex task that requires significant efforts of lecturer. The article proposes a concept of simulator designing that are supposed to be adopted in the educational process of civil aviation institutions based on hybrid approach to the virtual simulators designing. Such concept was applied in the development of methodology for designing of simulators for flight electronic support, which involves solving the problem of selective structural synthesis. The problem of selective structural synthesis of design solutions is described using a morphological tree and implies finding the graph edge that ensures meeting a set of rules with the constraints specified in the process of specification drawing up, which is replenished by the developer-user. Due to random nature, the structural optimization method implies a sequential search for possible options. A computer-aided system of simulator designing for flight electronic support systems was developed based on the methodology. The development of a computer-aided system of simulator designing for radio communications, radar and navigation equipment makes it possible to provide effective training of future pilots and air traffic control officers.

Разработка и апробация методики оценки эффективности взаимозаменяемости микросхем в радиолокационной аппаратуре на основании критической совокупности схемотехнических и параметрических характеристик

Разработка и апробация методики оценки эффективности взаимозаменяемости микросхем в радиолокационной аппаратуре на основании критической совокупности схемотехнических и параметрических характеристик

Highly Robust, Flexible, and Large‐Scale 3D‐Metallized Sponge for High‐Performance Electromagnetic Interference Shielding

AbstractElectromagnetic interference (EMI) is a type of pollution that is caused by the ubiquitous usage of electronic communication in general, and military radar equipment in particular. Even though this is a common problem for a long time, the fabrication of large‐area, flexible, and robust EMI shielding materials is still a challenge today. In this work, the 3D meshing strategy is simulated for most efficient utilization of metallic silver for X‐band EMI shielding, and propose a roll‐to‐roll (R2R) process to fabricate robust, flexible, and large‐scale EMI shielding sponge, silver nanowires/polyvinyl butyral (PVB) melamine sponge (AgPMS). Typically, 0.5 cm thick sponge has about 60 dB total EMI shielding efficiency (SE) in the microwave band, which is higher than for commercial EMI shielding sponges (about 45 dB) of the same thickness. AgPMS shows unchanged electrical properties after 1000 compression and bending cycles. Moreover, a AgPMS garment is made to demonstrate the excellent EMI shielding performance and remarkable flexibility of this material. Those properties suggest that AgPMS can be readily applied in challenging environments like hospitals, military installations, remote communication centers, and for any devices with curved surfaces.

Визначення максимального кута відхилення знімальної апаратури космічного апарата дистанційного зондування Землі при забезпеченні необхідної просторової розрізненості матеріалів космічного знімання

The mathematical expressions, specifying the estimation of the capabilities of remote sensing satellites with opto-electronic imaging equipment for observing the Earth’s surface with the necessary (predetermined) spatial resolution of the space imaging materials when deflecting the optical axis of on-board information complex, are obtained and substantiated in the article. The validity of the obtained expressions is proved by comparing the results of the solution of the direct and inverse problems of determining the spatial resolution of the space imaging materials when the optical axis of the on-board information complex of remote sensing satellites is deflected. Taking into account the deterioration of spatial resolution depending on the angle of deviation of the on-board information system of the satellites and the curvature of the Earth provides increasing the accuracy in determining the field of regard of satellites when modeling the state and changes in the space situation, as well as assessing their surface capabilities for space imaging. The capabilities of remote sensing satellites with opto-electronic equipment have been evaluated and it has been proved that the space imagery they receive cannot be applied to detect and identify (to the kind, class, type) objects of observation within the entire field of regard of imaging equipment, provided that the claimed spatial resolution of the space imaging materials. Prospects for further research are the refinement solution of practical problems in planning the use of on-board resource of remote sensing satellites, the improvement of algorithms for taking into account the possible observation of domestic territory (objects) with the help of foreign spacecraft’s and improving the methods of estimation of the remote sensing satellites with radar equipment.

Застосування безпілотних літальних апаратів для контролю параметрів радіолокаційних засобів зенітних ракетних комплексів

The article deals with the issues of improving the means of technical diagnostics of the radar equipment of surface-to-air missile systems. The authors justify the rationale of application of unmanned aerial vehicles to reduce the cost of checking the parameters of the radar equipment of surface-to-air missile systems for compliance with the requirements. This work defines the basic requirements for the tasks to be accomplished, components that should be added to the onboard equipment of the unmanned aerial vehicles, their flying characteristics and the main types of flight paths according to the tasks. It also identifies additional tasks for which the unmanned aerial vehicles can be engaged.

Design of radar portable maintenance auxiliary equipment

Aiming at the battlefield maintenance of radar and other weapons and equipment, a portable radar maintenance and detection equipment is developed. Planning the overall design principles of maintenance equipment, the equipment of the realization of the function and module, describes the testing equipment, the hardware structure and software design, suitable for field under the condition of individual maintenance support requirements.

Grey Evaluation Method of Radar Equipment Supportability Based on G1

A comprehensive evaluation method combining grey system theory and order relation analysis (G1) is proposed to solve the problems of various and uncertain factors affecting the supportability of radar equipment. Firstly, according to the requirement of radar equipment supportability, the evaluation index system of radar equipment supportability is constructed. Secondly, order relation analysis (G1) is used to determine the weight coefficient of each evaluation index. Finally, the grey scale and whitening weight function are determined by expert scoring value and grading standard, and the guarantee grade of radar equipment is obtained by using grey evaluation model. The accuracy of this method is verified by an example, which provides a new idea for the supportability evaluation of radar equipment.

Supportability Evaluation of Radar Equipment Based on Cloud Model and Improved RS-G1

In the context that factors affecting the supportability of radar equipment are numerous and of diverse dimensions, the existing index systems of supportability evaluation of radar equipment can hardly satisfy the continuously improving requirements of radar equipment support. First, aiming at the problem of transformation between quantitative description and qualitative concept, this paper converts the evaluation index set into an evaluation cloud model based on the cloud theory, generates the digital characteristics of the cloud model of the expert scoring by using the reverse cloud generator and the supportable comprehensive evaluation cloud drop chart of radar equipment by using forward cloud generator. Second, to make up for the shortcomings of the existing single weighting method, the Rough Set (RS) weighting method is improved with the introduction of the Order Relationship Analysis method (G1). Then this paper proposes the RS-G1 synthetic weighting method, and designs radar equipment supportability cloud evaluation based on this method. In the end, example shows that this method can evaluate the supportability level of radar equipment scientifically and effectively.

Overlying strata movement with ground penetrating radar detection in close-multiple coal seams mining

Longwall mining is a productive mining method that has been widely used in China, the United States, Australia, and Europe. However, due to the subsidence caused by coal mining activities, the phenomenon is complex, longwall mining brings the overburden movement issues accompany with the coal recovery. In subsidence trough, the resulting strata and surface ground movements are regarded as largely contemporaneous with mining, producing more or less direct effects of natural ecology. Ground penetrating radar has been widely used in geological hazard detection due to its high precision, but it is rarely employed in underground measuring the overlying strata movement above the longwall panel. In this article, there are five close-multiple coal seams (5#, 7#, 8#, 9#, 12# seams) within 70 m distance to be monitored in Qian Jiaying coal mine of Kailuan Coal Company in Hebei province. The 7#, 8#, 9#, 12# coal seams were already excavated in sequence. So the 5# coal seam is overmining above the gobs of four coal seams at the top. The ZTR12-series ground penetrating radar equipment is used to detect the development of fractures under the floor of the 5# coal seam. The ZTR12-series ground penetrating radar system has the capability of large depth detection and explosion proof to adapt to the working environment of underground coal mines and can realize fine detection and accurate identification. The maximum detection distance of reflection method can reach 50 m. The measurement results show that the 5# coal seam is in the fracture zone above the gobs of four coal seams, and the caved zone of lower coal seam develops to fine sandstone of the 5# coal seam floor. The ground penetrating radar has shown much promise in the detection of overlying strata movement.

YOLO-RD: A lightweight object detection network for range doppler radar images

Under the condition of limited memory and computing power of radar aircraft equipment, large-scale object detection network based deep learning can not be deployed. Based on the darknet framework, Our paper proposes a lightweight object detection network for range doppler(RD) radar images: YOLO-RD, and builds a lightweight RD dataset: mini-RD, for efficient network training. Firstly, YOLO-RD extracts features from the input image through a series of small convolutional. Secondly, the dense block connection module is used to design the backbone extraction network. Finally, the prediction layer is combined with multi-scale features for prediction. Experiments show that YOLO-RD has achieved good results on the mini-RD dataset with a smaller memory budget, with a detection accuracy of 97.54%.

О ПРИМЕНЕНИИ ТЕОРИИ РАЗМЕРНОСТИ И НЕЛИНЕЙНОЙ ДИНАМИКИ В НОВОМ ВИДЕ И МЕТОДЕ РАДИОЛОКАЦИИ

Intensive evolution of the modern radar equipment and technologies put new requirements for the radio location theory as well. The work objective is not only to state our viewpoint, to define and discover a new type and a new method of radio location on the basis of fractal-and-scaling or scale-invariant principles but also, just as important, to call attention to conventional questions of the general statistical theory from the point of view of the fractal analysis, fractional calculation and the global fractal-and-scaling approach which was designed and being developed by the author during last 40 years in IREE AS of USSR (IREE RAS). The author was the first who proposed and substantiated the new type and the new method of the modern radio location namely fractal-scaling or scale-invariant radio location (Potapov, 2017, 2018). Efficiency of functionals which are determined by topology, fractional dimension, and texture of a sensed multidimensional signal was proved for synthesis of the new non-energy detectors of low-contrast objects in presence of noise. Fractal radio location is based on three postulates: - intellectual signal/image processing which is based on the fractional measure and scaling effects theory for calculating the field of fractal dimensions; - sampling of a received noisy signal relates to a class of stable non-Gaussian distributions of probabilities of fractal dimension D; - the topology maximum at the energy minimum of a received random signal. Sensitivity of a radio system has been confirmed (what is equal to an increase of the range) while using fractal and textural signature in topological detectors. It results in drastic changes in the mathematical apparatus of the theoretical radio location. The research was supported by the RAS Presidium Program «Nonlinear dynamics: fundamental problems and applications».

A Fuzzy Comprehensive CS-SVR Model-based health status evaluation of radar

The purpose of Fuzzy Comprehensive CS-SVR Model (FCCS-SVR) is to evaluate and monitor the health status of a radar equipment and then keep its safe operation. Due to reasons such as few samples, slow changes and the nonlinear structure of data of fault monitoring signal, the health status evaluation of a radar system is quite difficult. By establishing the evaluation index system of a radar, the combination of AHP method and Entropy weight method is studied in this paper. In order to evaluate the value of health status, several optimization algorithms including PSO, GA, BA and CS are used for optimizing the parameters of SVR model. Meanwhile, in order to avoid the problem that the system is at the edge of the state, a radar health assessment method based on the combination of Fuzzy Comprehensive Evaluation and Cuckoo Search-Support Vector Regression (CS-SVR), which is named as Fuzzy Comprehensive CS-SVR (FCCS-SVR), is further proposed. The result of case analysis reflects that the state evaluation of the radar system is realized. The system performance analysis shows that the use of FCCS-SVR evaluation method provides a high recognition rate and can accurately assess the health status of the radar system.

Room-temperature production of silver-nanofiber film for large-area, transparent and flexible surface electromagnetic interference shielding

A kind of pollution known as electromagnetic interference (EMI), which results from ubiquitous usage of various electronic communication and military radar equipment, has been receiving increasing attention recently. However, large-area EMI shielding on transparent and/or curved surfaces, including building windows, curved glass wall, and special requirements spaces (SRSs), remains hard to achieve. In this paper, a silver nanofiber (AgNF) based flexible and transparent EMI shielding film was successfully assembled via a room-temperature roll-to-roll production method. For transparent application scenario, AgNF with 89% transmittance in visible range and 1 μm thickness shows ~20 dB shielding efficiency (EMI SE). On the other hand, total shielding (>50 dB) is obtained when the thickness of AgNF increases to 10 μm, while its transmittance in visible range remains higher than 75%. Considering the facile and scale-free production technology, this material can be readily applied in large-scale, transparent, and/or SRSs EMI shielding.

HANDHELD SPEED METERS IN POLAND AND THE STANDARD OF THE HUMAN RIGHTS OF THE DEFENCE

This chapter describes the legal basics and the practice of using handheld radar and laser devices in speeding cases. The analysis concerns normative frameworks, unfortunately neglected, as well as indicates problems occurring in cases of offences related to speeding. In judicial practice, radar devices Iskra and lidar devices, colloquially called Ultralyte lasers, are most commonly used .Unfortunately, in judicial practice, the application of the normative framework for the use of lidar and radar equipment is subject to the principle in dubio pro radar.

Analysis of fog at Xianyang Airport based on multi-source ground-based detection data

In order to improve the accuracy of fog forecast at Xianyang Airport, microwave radiometer, wind profiling radar and other equipment are utilized to detect fog. With the long term detection data from the equipment mentioned above, this paper analyzes the altitudinal-temporal variation characteristics of wind, temperature, and relative humidity during fog weather. It also tallies up the variation characteristics of the three meteorological factors at different heights as visibility and time changes. The findings are listed as follows. During autumn and winter, fog usually appears between 22:00 BT and 13:00 BT next day at Xianyang Airport, with relatively stable atmospheric structure. During fog, when the height is below 300 m, the average relative humidity is >75%, and the average horizontal wind speed is <3 m/s, along with a weak downdraft. In September and October, there is mainly southwest wind at low levels during fog weather, the height of radiation inversion layer within 300 m. In November, December and January, it is mainly northeast wind at low levels during fog, with rather thick radiation inversion layer. When the visibility is 1500 m in mist, if the temperature drops by 3 °C and the relative humidity rises by 9% in September and October, the visibility decreases to <1000 m accordingly; if the temperature drops by 6 °C in November (or it drops 8 °C in December and January), the inversion layer thickens, the relative humidity increases by 15%, then the visibility reduces to <1000 m. These findings can provide scientific basis to improve the accuracy of fog forecast at Xianyang Airport.

Certifying Navigational Skills: A Video-based Study on Assessments in Simulated Environments

In Maritime Education and Training (MET) where students are trained for professions with high standards of safety, the use of simulators is taken to provide opportunities for safe and cost-effective training. Although the use of simulators for training and certifying technical proficiency and so-called non-technical skills is well established and regulated by international standards, previous research suggests that simulator-based assessment has been poorly implemented in the MET system. Now the challenge is to contribute with knowledge about how to conduct consistent, unbiased, and transparent assessments of navigational skills and competencies. However, in current research it is not evident how training of non-technical skills in simulated environments should be assessed. The aim of this study is to explore the pedagogical challenges instructors face when assessing students' navigational skills and competencies in a simulated environment. The study is based on video-recorded data from the certification part in a navigation course for second year master mariner students. A situated approach to cognition and learning is employed to analyze the co-construction of assessment in the simulated exercises by means of instructors' questions and students' answers. Results reveal an assessment practice where the students are still developing their navigational skills with instructional support from examiners whilst being certified on using Radar equipment in accordance to COLREG.

General Analysis of Resolution Enhancement on Time-Synchronized Sampling and its Multi-Resolution Solution in 20GSPS Acquisition System

Multiple resolutions have become a new feature required in ultra-fast data acquisition systems (UF-DASs) for various high-end applications, especially for large-scale physical experiments and radar equipment. However, plenty of repetitive efforts are paid to build various UF-DASs with different resolutions for many similar purposes. In this paper, a system-level sampling solution featuring multi-resolution is explored for UF-DASs to make the trade-off between accuracy and speed. Firstly, a resolution enhancement mechanism based on a time-synchronized sampling technique is studied more generally with probabilistic and statistical theory, and its applicable premise is discussed quantificationally at the same time. Then, a hardware-based reconfigurable structure for the purpose of multi-resolution high-speed sampling is discussed with the combination of time-interleaved and time-synchronized sampling methods. Furthermore, to verify the proposed theory, a prototype with a maximal 20GSPS sampling rate and different resolutions of 8,9,10-bit is established. The experimental results show that three vertical resolutions of 8, 9 and 10-bit are achieved in the same prototype, and the effective-number-of-bit (ENOB) in the two higher resolution modes has been improved remarkably from a single low-resolution analog-to-digital converter (ADC). Therefore, the proposed theory and multi-resolution sampling solution are important guides to the resolution trade-off requirement in ultra-fast acquisition systems.

Comparison of Multichannel Ground Penetrating Radar Equipment for Detecting Road Cavities

Comparison of Multichannel Ground Penetrating Radar Equipment for Detecting Road Cavities

The Method for Time Calculation of Information Taking in the Aperture Synthesis Radar Station

Introduction. The main requirements for modern air\-borne radar equipment are obtaining ultra-high resolution radar images at a considerable distance (several tens of kilometers) in a time scale that is close to real as possible. However, there are certain limitations that currently complicate the possibility of obtaining an image of a high resolution at a considerable distance, for example, it is necessary to take into account the sphericality of the wave front of the sounding signal. In the given article the method for time calculation of radiological information taking at use of the determining filter and additional algorithms in the aperture synthesis radar station and calculated the time, which is necessary for reception of the image, using the aperture synthesis radar with the various distinctive abilities. Results of the research. To determine the time to get radar images to a modern computer, it is necessary to calculate: - the number of readings per element of differentiation along the distance in the strip, over the sloping range; - the number of signal counts that are stored in a single channel for coherent filtration at the synthesis interval; - the number of channels in the strip of inspection; - the number of computer cycles needed to get the total number of readings per element of distinction; - the number of cycles for using additional algorithms in processing trajectory signals; - the time required to view the area of the site. Conclusions. An analysis of the calculated time for obtaining ultra-high resolution radar information using a matching filter and additional algorithms suggests that radar monitoring throughout the flight is not appropriate as it takes quite a long time to process radar information. Therefore, it is necessary to initially handle the received radar image with low resolution, and in the case of identifying objects of interest, apply additional algorithms for processing information, to obtain a detailed radar image of a specific area or object with the necessary resolution.

Calculation of safe speed and minimally admissible distance of closing of ships during radar information usage

Exceeding the safe speed and the minimum allowable distance when ships approach each other is considered as one of the main reasons for their collision, especially when using radar information when sailing in reduced visibility or in confined areas. When assigning a safe speed, among other factors, the rules recommend to take into account the state of visibility of the maneuverable capabilities of the ship, especially the distance required to completely stop the ship, as well as the characteristics, efficiency and limitations of radar equipment. But, besides the quality recommendations in the COLREGs, there are no quantitative estimates of the safe speed and excessive convergence of the ships. Each navigator subjectively assigns a safe speed and determines the minimum allowable approach distance for ships. Therefore, the development of a universal method for calculating safe speed and the minimum allowable distance when using radar information is relevant, and the method itself is effective when used on ships, especially when sailing in difficult navigation areas and with limited visibility. The developed method allows to automate the choice of safe speed and eliminate the subjective factor when it is appointed navigator