Four-antenna amplitude direction finder: statistical synthesis and experimental research of signal processing algorithm

The subject of this study is the algorithms for measuring the angular positions of radio emission sources. The goal of this study is to develop an improved algorithm for signal processing in amplitude direction finders that will provide several unambiguous measurement angles at high steepness of the discrimination characteristic by combining measurements of systems with different widths of antenna patterns. The task: to develop an optimal signal processing algorithm for a four-antenna amplitude direction finding system, two antennas of which have a wide radiation pattern and the other two have a narrow one; to test the overall performance of the resulting algorithm by simulating the direction finder; to develop and conduct a study of an experimental model of a four-antenna direction finder, which includes two antennas with wide radiation patterns, two antennas with narrow radiation patterns, radio frequency paths, and a signal processing unit that implements the developed algorithm; to analyze the effectiveness and features of the application of the developed algorithm, and to compare the results of simulation modeling and experimental research. The methods used are statistical methods and optimal solutions for solving problems of statistical synthesis of signal processing algorithms in passive radio systems, computer simulation modeling methods, and experimental research methods. The following results were obtained. The algorithm for signal processing in a four-antenna direction finding system was synthesized using the maximum likelihood method. By simulation modeling, the overall effectiveness of measurement integration in multi-antenna amplitude direction finders was confirmed, and the peculiarities of the synthesized algorithm application were revealed, namely, the need to introduce additional proportionality coefficients into the measurement channels. During the experimental studies of the developed model of the direction finder, the results of the simulation modeling were confirmed. Conclusions. To determine the direction of radiation sources by amplitude direction finders, it is advisable to simultaneously use systems with wide and narrow antenna patterns, the measurements of which are combined by the proposed algorithm. This makes it possible to simultaneously expand the range of unambiguous measurement angles and increase the accuracy of measurements within the equal-signal zone. The disadvantage of using the algorithm is the nonlinear form of the obtained discrimination characteristics and the need to determine additional proportionality coefficients heuristically

Non-destructive elemental analysis of steel 30 after boron coating with modern equipment for material quality control

Мікрорентгенофлуоресцентний аналіз набув значного поширення як у промисловості, так і науці завдяки своїй універсальності, точності й швидкості вимірювань, а також простоті експлуатації. Метод заснований на залежності інтенсивності рентгенівської флуоресценції від концентрації елемента в зразку. При опроміненні зразка потужним потоком випромінювання рентгенівської трубки виникає характеристичне флуоресцентне випромінювання атомів, яке пропорційне їх концентрації в зразку.Micro x-ray fluorescence analysis is widespread in industry and science due to its flexibility, accuracy and measurement speed, and ease of use. The method is based on the dependence of micro X-ray fluorescence intensity of the element concentration in the sample. When irradiating the sample stream powerful X-ray tube fluorescent radiation characteristic radiation arises atoms, which is proportional to their concentration in the sampl

Особистість сучасного керівника в аспекті теорії духовного лідерства

Стаття присвячена актуальним проблемам дослідження питань лідерства. Розг-лядаються сутність поняття "лідерство", теорії лідерства. Особлива увага приділяїться аналізу теорії духовного лідерства; розкривається суть основних чеснот, необхідних сучасному керівникові-лідерові: великодушність, смиренність, мужність, самовладання і справедливість.Article is devoted to the problems of the leadership study. The essence of the concept of "leadership," the theories of leadership are considered. Special attention is paid to the analysis of the spiritual leadership theory, the essence of virtues needed modern manager-leader: generosity, humility, prudence, courage, self-control and justice is revealed

Modified Antiretroviral Treatment Access Study (MARTAS): A Randomized Controlled Trial of the Efficacy of a Linkage‐to‐Care Intervention Among HIV-Positive Patients in Ukraine

Between October 2015 and March 2018, we conducted the Modified Antiretroviral Treatment Access Study (MARTAS), a nurse-delivered case management intervention to improve linkage-to-care for persons recently tested HIV positive. Adult participants from nine urban clinics in three regions of Ukraine were randomized to either MARTAS or standard of care (SOC) using individual, parallel, two-arm design. The main study outcome was linkage-to-care (defined as registration at an HIV clinic) within a 3-month period from enrollment in the study. Intention-to-treat analysis of MARTAS (n = 135) versus SOC (n = 139) showed intervention efficacy in linkage to HIV care (84.4% vs. 33.8%; adjusted RR 2.45; 95% CI 1.72, 3.47; p < 0.001). MARTAS is recommended for implementation in Ukraine and may be helpful in other countries with similar gaps in linkage-to-care. Clinicaltrials.gov registration number: NCT02338024