Поликультурное образование как направление деятельности открытого университета

Авторы дают определение понятий "поликультурное образование" и "открытый университет"; обращаются к правовым актам и учебным программам, целью которых является поликультурное просвещение, и приходят к выводу о значимости этого направления в деятельности открытого образования в условиях многокультурного информационного общества

2018 Beam-park observations of space debris with the EISCAT radars

Source at https://conference.sdo.esoc.esa.int/proceedings/neosst1/paper/480.Monitoring the evolution of the space debris environment requires regular radar observations of the space debris population. This study presents the results from 24 hours of beam-park observations of space objects conducted simultaneously with the EISCAT Svalbard and Tromsø radars on and between January 4th and 5th, 2018. The measurements are processed with a new matched filter bank analysis program, which doubles the coherent integration time, and hence sensitivity, compared with the previous program. We observe 2077 objects with the Tromsø radar and 2400 objects with the Svalbard radar. The detections are correlated with the NORAD catalog. We find that 68% of the Tromsø and 85% of the Svalbard radar detections are from objects in the NORAD catalog, with most of the catalog object detections being in the side lobes of the radar antenna. The beam-park data are compared with a simulated beam-park experiment for catalog objects. The simulation uses a radar detection model that includes the effects of coherent integration and an antenna beam shape with side lobes. We find that the simulation agrees well with the measurements, indicating that the radar sensor response is accurately modeled. Our results highlight the importance of modeling antenna side lobes when analyzing beam-park measurements. Not taking taking into account side lobe detections can lead to an underestimation of radar cross-sections and an overestimation of population density

EISCAT 3D: the next generation international atmosphere and geospace research radar

EISCAT 3D is the next generation international atmosphere- and geospace research radar in Arctic Europe. The EISCAT 3D construction started in September 2017 and the radar system is expected to be operational in the end of 2021. The EISCAT 3D facility will be distributed across three sites in Northern Scandinavia - in Skibotn, Norway, near Kiruna in Sweden, and near Karesuvanto in Finland. Each site will consist of about 10.000 antennas fed by a powerful 5 MW transmitter at Skibotn and a receiver at each of the three sites. EISCAT 3D is designed for novel measurement techniques, ones which have never been combined in one radar system: volumetric-, aperture synthesis- and multi-static imaging, tracking- and adaptive experiments, together with continuous operations. This unique versatility will enable tracking hard targets such as space debris, NEO:s and meteor head echoes in parallel with radar experiments to solve fundamental questions of cross-layer coupling in the atmosphere, solar-terrestrial interactions and plasma turbulence. In this presentation we review the current project status and outline the EISCAT 3D capabilities for contributing to Space Surveillance and Tracking (SST).submittedVersio

2018 BEAM-PARK OBSERVATIONS OF SPACE DEBRIS WITH THE EISCAT RADARS

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Resolving the ambiguous direction of arrival of weak meteor radar trail echoes

Abstract Meteor phenomena cause ionized plasmas that can be roughly divided into two distinctly different regimes: a dense and transient plasma region co-moving with the ablating meteoroid and a trail of diffusing plasma left in the atmosphere and moving with the neutral wind. Interferometric radar systems are used to observe the meteor trails and determine their positions and drift velocities. Depending on the spatial configuration of the receiving antennas and their individual gain patterns, the voltage response can be the same for several different plane wave directions of arrival (DOAs), thereby making it impossible to determine the correct direction. A low signal-to-noise ratio (SNR) can create the same effect probabilistically even if the system contains no theoretical ambiguities. Such is the case for the standard meteor trail echo data products of the Sodankylä Geophysical Observatory SKiYMET all-sky interferometric meteor radar. Meteor trails drift slowly enough in the atmosphere and allow for temporal integration, while meteor head echo targets move too fast. Temporal integration is a common method to increase the SNR of radar signals. For meteor head echoes, we instead propose to use direct Monte Carlo (DMC) simulations to validate DOA measurements. We have implemented two separate temporal integration methods and applied them to 2222 events measured by the Sodankylä meteor radar to simultaneously test the usefulness of such DMC simulations on cases where temporal integration is possible, validate the temporal integration methods, and resolve the ambiguous SKiYMET data products. The two methods are the temporal integration of the signal spatial correlations and matched-filter integration of the individual radar channel signals. The results are compared to Bayesian inference using the DMC simulations and the standard SkiYMET data products. In the examined data set, ∼ 13 % of the events were indicated as ambiguous. Out of these, ∼ 13 % contained anomalous signals. In ∼ 95 % of all ambiguous cases with a nominal signal, the three methods found one and the same output DOA, which was also listed as one of the ambiguous possibilities in the SkiYMET analysis. In all unambiguous cases, the results from all methods concurred