Определение скорости движения и дальности быстродвижущихся объектов в РЛС с непрерывным линейно-частотно-модулированным излучением с использованием автокорреляционной схемы

Introduction. A hardware basis of modern Advanced Driver Assistance Systems (ADAS) consists of millimeterrange radars, characterized by a relatively short range (meters – tens of meters). At the same time, improving of traffic safety requires to increase the range at least to several hundred meters. The one way to achieve such values is to increase wavelength of a probing signal, to use the centimeter range of wavelengths, for example. The paper represents a detailed description of main steps of signal processing algorithm in the model of the ADAS low-power centimeter range radar, which provides fast-moving objects speed and range definition.Aim. Development of an algorithm for estimating the range and the speed of targets by an autocorrelation radar with a wide-band continuous linear frequency modulation (linear FM) signal in order to increase the rate of the ADAS system estimates formation.Materials and methods. The proposed algorithm is based on the methods of primary and secondary digital processing of radar signals. The model of a centimeter-range autocorrelation radar with a broadband continuous linear FM probing signal was used for practical researches. MATLAB software was used to process the received signal samples.Results. The algorithm has been developed to determine the speed and the range of fast-moving objects in conditions when their movement during the evaluation interval significantly exceeds the radar range resolution. The use of simplified Kalman filtering for inter-period secondary signal processing allowed to increase significantly the stability of the algorithm. In a full-scale experiment using the low-power radar model with continuous radiation of the centimeter range, it was shown that a stable assessment of a real car speed and range was provided at a distance of at least about one kilometer.Conclusion. The results of the field experiment make it possible to draw conclusions that the proposed algorithm is highly robust even in the absence of inter-period secondary processing. Its usage allows one to improve the stability of the algorithm without considerable additional computational costs. It is possible because near-linear dynamics of the observation object and of the radar carrier makes it sufficient to use a simplified implementation of Kalman filter in the form α-β-algorithm.Введение. Аппаратную основу современных систем помощи водителю (ADAS) обычно составляют радиолокационные станции миллиметрового диапазона, характеризующиеся относительно небольшой дальностью действия (единицы-десятки метров). В то же время повышение безопасности движения требует ее увеличения как минимум до нескольких сотен, и одним из путей достижения таких значений является увеличение длины волны зондирующего сигнала, например, переход в сантиметровый диапазон длин волн. В работе приведено подробное описание основных этапов работы алгоритма обработки сигнала в макете маломощной РЛС системы ADAS сантиметрового диапазона, обеспечивающего определение скорости движения и дальности быстродвижущихся объектов.Цель работы. Разработка алгоритма оценки дальности и скорости движения целей в РЛС с широкополосным непрерывным линейно-частотно-модулированным (ЛЧМ) сигналом на базе автокорреляционной схемы в интересах повышения скорости формирования оценок для системы ADAS.Материалы и методы. Предлагаемый алгоритм базируется на методах первичной и вторичной цифровой обработки радиолокационных сигналов. Для проведения практических исследований использовался макет РЛС сантиметрового диапазона, собранной по автокорреляционной схеме, с широкополосным непрерывным ЛЧМ зондирующим сигналом. Для обработки зарегистрированной выборки отсчетов принятого сигнала применялась среда MatLab.Результаты. Разработан алгоритм, обеспечивающий определение скорости и дальности быстродвижущихся объектов в условиях, когда их перемещение за интервал оценивания существенно превышает разрешение РЛС по дальности. Использование упрощенной калмановской фильтрации для межпериодной вторичной обработки сигнала позволило существенно повысить устойчивость работы алгоритма. В ходе натурного эксперимента с использованием макета маломощной РЛС с непрерывным излучением сантиметрового диапазона показано, что устойчивая оценка скорости движения и дальности реального автомобиля обеспечивается на расстоянии как минимум порядка одного километра.Заключение. Результаты проведенного натурного эксперимента позволили сделать вывод о высокой робастности предложенного алгоритма даже при отсутствии межпериодной вторичной обработки. Ее использование позволяет еще больше повысить устойчивость работы алгоритма при практически полном отсутствии дополнительных вычислительных затрат, так как близкий к линейному характер динамики объекта наблюдения и автомобиля-носителя РЛС позволяет полагать достаточным использование упрощенной реализации фильтра Калмана в форме α-β-алгоритма

On the Effect of Dust Particles on Global Cloud Condensation Nuclei and Cloud Droplet Number

Aerosol-cloud interaction studies to date consider aerosol with a substantial fraction of soluble material as the sole source of cloud condensation nuclei (CCN). Emerging evidence suggests that mineral dust can act as good CCN through water adsorption onto the surface of particles. This study provides a first assessment of the contribution of insoluble dust to global CCN and cloud droplet number concentration (CDNC). Simulations are carried out with the NASA Global Modeling Initiative chemical transport model with an online aerosol simulation, considering emissions from fossil fuel, biomass burning, marine, and dust sources. CDNC is calculated online and explicitly considers the competition of soluble and insoluble CCN for water vapor. The predicted annual average contribution of insoluble mineral dust to CCN and CDNC in cloud-forming areas is up to 40 and 23.8%, respectively. Sensitivity tests suggest that uncertainties in dust size distribution and water adsorption parameters modulate the contribution of mineral dust to CDNC by 23 and 56%, respectively. Coating of dust by hygroscopic salts during the atmospheric aging causes a twofold enhancement of the dust contribution to CCN; the aged dust, however, can substantially deplete in-cloud supersaturation during the initial stages of cloud formation and can eventually reduce CDNC. Considering the hydrophilicity from adsorption and hygroscopicity from solute is required to comprehensively capture the dust-warm cloud interactions. The framework presented here addresses this need and can be easily integrated in atmospheric models

Modulating effect of liposomal miR-101 on the processes of amyloidogenesis, smell, sleep and neuroinflammation in experimental Alzheimer's disease

The current therapy for Alzheimer's disease does not give patients a chance of recovery. Therefore, it is relevant to study the novel factors of influence, in particular microRNA, on the pathogenic mechanisms of amyloidosis. The aim of this work was to determine the effect of miR-101 on early predictors of amyloidosis in experimental Alzheimer's disease in animals. The study was carried out on 25 male rats of 14 months of age. A model of Alzheimer's disease was created by intrahippocampal administration of Aβ40 aggregates to animals. Ten days later, a 10-day course of nasal administration of miR-101 in liposomes was launched. The level of endogenous Aβ42 and cytokines (TNFα, IL-6 and IL-10) was determined in the supernatants of the nerve tissues of the target brain structures (hippocampus, olfactory bulbs, and olfactory tubercles). A neuroethological method of presenting smells of isovaleric acid and peanut butter was used to assess the olfactory system functional state in the experimental rats. In the course of polygraphic registration of the sleep-wakefulness cycle, the representation of wakefulness and individual sleep phases, as well as proportion of incomplete and complete sleep cycles were determined. It was shown that injection of Aβ40 aggregates into the hippocampus simulates an amyloidogenic state in the rat’s hippocampus and olfactory tubercles, but not in the olfactory bulbs. Moreover, a pro-inflammatory state was registered in the hippocampus of the animal brain (an increase in the concentration of pro-inflammatory cytokines TNFα and IL-6), while the cytokine level in the olfactory bulbs and tubercles did not change. When studying the functional state of olfactory analyzers in the rats with Alzheimer's disease, we revealed negative changes in behavioral response to the smell of isovaleric acid and peanut butter. In terms of somnograms, the Aβ40 toxicity caused reduction in the deep slow-wave sleep stage combined with deficiency of the paradoxical sleep phase, and predominance of incomplete sleep cycles. Nasal therapy with miR-101 in liposomes normalized the level of Aβ42 in the hippocampus and olfactory tubercles and decreased the level of proinflammatory cytokines in the hippocampus. MiR-101 prevented olfactory disfunctions in assessing smells of isovaleric acid and peanut butter, increased the ratio of deep slow-wave sleep and paradoxical sleep in the cycle structure and restored proportion of complete sleep cycles in animals. Thus, liposomal miR-101 has an anti-amyloidogenic and anti-inflammatory effect in rats with a model of Alzheimer's disease. It helps to restore the functional state of olfactory analyzer and optimize structural organization of the sleep-wakefulness cycle in sick animals

The Construction of Quantum Field Operators: Something of Interest

We draw attention to some tune problems in constructions of the quantum-field operators for spins 1/2 and 1. They are related to the existence of negative-energy and acausal solutions of relativistic wave equations. Particular attention is paid to the chiral theories, and to the method of the Lorentz boosts.Comment: 31 pages, no figures. The invited talk at the VIII International Workshop "Applied Category Theory. Graph-Operad-Logic", San Blas, Nayarit, Mexico, January 9-16, 2010, and at the 6th International Conference on the Dark Side of the Universe (DSU2010), Leon, Gto, Mexico, June 1-6, 201

Cooper pairing of electrons and holes in graphene bilayer: Correlation effects

Cooper pairing of spatially separated electrons and holes in graphene bilayer is studied beyond the mean-field approximation. Suppression of the screening at large distances, caused by appearance of the gap, is considered self-consistently. A mutual positive feedback between appearance of the gap and enlargement of the interaction leads to a sharp transition to correlated state with greatly increased gap above some critical value of the coupling strength. At coupling strength below the critical, this correlation effect increases the gap approximately by a factor of two. The maximal coupling strength achievable in experiments is close to the critical value. This indicated importance of correlation effects in closely-spaced graphene bilayers at weak substrate dielectric screening. Another effect beyond mean-field approximation considered is an influence of vertex corrections on the pairing, which is shown to be very weak.Comment: 6 pages, 5 figures; some references were adde

АЛГОРИТМ ОБРАБОТКИ СИГНАЛОВ В РАДИОЛОКАЦИОННОЙ СИСТЕМЕ С НЕПРЕРЫВНЫМ ЧАСТОТНО-МОДУЛИРОВАННЫМ ИЗЛУЧЕНИЕМ В ИНТЕРЕСАХ ОБНАРУЖЕНИЯ МАЛОЗАМЕТНЫХ ВОЗДУШНЫХ ОБЪЕКТОВ, ОЦЕНКИ ИХ ДАЛЬНОСТИ И СКОРОСТИ ДВИЖЕНИЯ

Nowadays the interest in search of ways of improving the efficiency of small radar cross-section aerial objects detection and localization rises against the background of widespread use of light and unmanned aerial vehi-cles. As a result, researchers pay attention to radar systems (RS) with continuous linear frequency modulation (linear FM) signal. The use of such signals gives the measurable opportunity to reduce radar system peak-speech power and to cut the cost and weightsize parameters of the RS. The paper observes low-power ground based radar implementation prospects for purposes of detection and estimation of motion rates of small-sized aerial objects. The proposed algorithm of radar signals processing enables to simplify the detection of such tar-gets. The paper reveals the structure and defines the steps of the algorithm. The fundamental for the algorithm under consideration is the method of the range-Doppler image composition of the scanned area using digital signal processing. The paper presents the results of the algorithm operation in the low-power RS of C-band radar, obtained by processing of quadrotor echo-signals during the real experiment. The results show successful solvation of the applied problem of detection and tracking on the small-sized aerial object with the radar cross-section equal to less than 0.5 m2 and the spectrum of secondary radiation characterized by the expressed multimodality. The results of the experiment validate the application of the algorithm and demonstrate the possibility of the algorithm implementation in design of portable RS and automated target acquisition centers for detecting and tracking of the small-sized aerial targets (both, single as multi agent) with the information display on operator control panel.На фоне повсеместного использования беспилотных летательных аппаратов и легкомоторной авиации растет интерес к поиску путей повышения эффективности локализации и определения параметров движения воздушных объектов с малой эффективной площадью рассеяния. В связи с этим закономерно внимание к радиолокационным системам (РЛС) с непрерывным линейно-частотно-модулированным (ЛЧМ) излучением. Использование таких зондирующих сигналов позволяет значительно снизить пиковую мощность РЛС и уменьшить ее массогабаритные и стоимостные характеристики. Статья посвящена исследованию перспективы применения маломощной наземной РЛС с непрерывным ЛЧМ-сигналом в интересах обнаружения, а также определения координат и параметров движения малозаметных воздушных объектов. Предложен алгоритм обработки радиолокационных сигналов, позволяющий упростить процедуру обнаружения таких целей, раскрыта структура и приведено описание этапов алгоритма. В основе рассматриваемого алгоритма лежит методика формирования дальностно-доплеровского портрета зоны обзора с использованием цифровой обработки сигнала. Приведены результаты применения алгоритма в маломощной РЛС С-диапазона, полученные при обработке эхосигналов квадрокоптера, зарегистрированных в ходе натурного эксперимента. Показано успешное решение практической задачи обнаружения и сопровождения малоразмерного воздушного объекта с эффективной площадью рассеяния до 0.5 м2, спектр вторичного излучения которого характеризуется выраженной многомодальностью. Результаты эксперимента подтвердили практическую значимость предлагаемого алгоритма и возможность его реализации при создании мобильных переносных радиолокационных комплексов и постов автоматического обнаружения и сопровождения малозаметных одиночных и групповых целей с выдачей информации на пульт оператора

Extra Dirac Equations

This paper has rather a pedagogical meaning. Surprising symmetries in the $(j,0)\oplus (0,j)$ Lorentz group representation space are analyzed. The aim is to draw reader's attention to the possibility of describing the particle world on the ground of the Dirac "doubles". Several tune points of the variational principle for this kind of equations are briefly discussed.Comment: REVTeX 3.0, 14p

Majorana Neutrino: Chirality and Helicity

We introduce the Majorana spinors in the momentum representation. They obey the Dirac-like equation with eight components, which has been first introduced by Markov. Thus, the Fock space for corresponding quantum fields is doubled (as shown by Ziino). The particular attention has been paid to the questions of chirality and helicity (two concepts which frequently are confused in the literature) for Dirac and Majorana states.Comment: Misprints corrected. 19 pp., no figures. The talk given at the QTS7 Conference (Prague, Czech Republic, August 7-13, 2011

Синтез поликатионных амфифилов на основе холевой кислоты

A synthesis of polycationic amphiphiles on the basis of cholic acis with potential antimicrobial and transfection activities has been described.Описан синтез поликатионных амфифилов на основе холевой кислоты с потенциальной антимикробной или трансфицирующей активностью

Neutral Particles in Light of the Majorana-Ahluwalia Ideas

The first part of this article (Sections I and II) presents oneself an overview of theory and phenomenology of truly neutral particles based on the papers of Majorana, Racah, Furry, McLennan and Case. The recent development of the construct, undertaken by Ahluwalia [{\it Mod. Phys. Lett. A}{\bf 9} (1994) 439; {\it Acta Phys. Polon. B}{\bf 25} (1994) 1267; Preprints LANL LA-UR-94-1252, LA-UR-94-3118], could be relevant for explanation of the present experimental situation in neutrino physics and astrophysics. In Section III the new fundamental wave equations for self/anti-self conjugate type-II spinors, proposed by Ahluwalia, are re-casted to covariant form. The connection with the Foldy-Nigam-Bargmann-Wightman- Wigner (FNBWW) type quantum field theory is found. The possible applications to the problem of neutrino oscillations are discussed.Comment: REVTEX file. 21pp. No figure