Analisis Kinerja Sistem Doppler VHF Omnidirectional Range dan Distance Measuring Equipment pada Navigasi Penerbangan

Navigasi udara merupakan kegiatan untuk mengarahkan transportasi udara dari satu tempat ke tempat yang lain agar tidak keluar dari jalurnya. Sistem transmisi sinyal pada Doppler VHF Omnidirectional Range (DVOR) belum sepenuhnya optimal karena persentase sinyal modulasinya sering mengalami peningkatan yang berakibat pada munculnya kondisi sinyal over-modulated. Deteksi sinyal interogasi maupun sinyal balasan pada Distance Measuring Equipment (DME) mengalami hambatan disebabkan oleh waktu tunda dan jarak pulsa yang tidak sesuai. Pada penelitian ini, akan dilakukan analisis kinerja sistem DVOR-DME dengan membandingkan nilai parameter dan nilai kondisi normal. Berdasarkan analisis kinerja sistem, didapatkan bahwa sistem DVOR-DME AirNav Indonesia Distrik Tanjungpinang beroperasi dengan normal. Nilai optimal 30Hz MOD dan 9960Hz MOD pada DVOR berada pada rentang nilai normal yaitu sebesar 30%. Nilai optimal delay dan spacing pada DME berada pada rentang nilai delay normal dan nilai spacing normal yaitu sebesar 50,01 μs dan 12,02 μs

ANALISIS SISTEM NAVIGASI UDARA MODEL 432 (DVOR) UNTUK MEMANDU PESAWAT MENUJU BANDARA

Pada awalnya, navigasi untuk memandu pesawat kebandara tujuan hanya dengan menggunakan penglihatan saja dan memiliki kemampuan yang masih terbatas. Peralatan navigasi yang diperlukan dan memiliki kemampuan yang tidak terbatas (kontinu) untuk memandu pesawat menuju bandara adalah DVOR. DVOR yaitu suatu peralatan navigasi udara untuk memandu pesawat agar bisa mendarat sempurna pada bandara yang dituju dengan cara memberikan informasi berupa azimuth atau bearing buatan yang menggunakan frekuensi akibat adanya efek doppler, bukan azimuth arah sebenarnya kepada pesawat melainkan informasi terhadap titik DVOR ground station yang ada pada Bandara Kualanamu. Metode yang digunakan pada penelitian ini adalah Metode Efek Doppler. Berdasarkan arah mendarat runway 23, OBS menunjukkan azimuth / bearing 110º sebagai panduan arah bandara tujuan, dengan frekuensi Efek Doppler antena sideband 112.209.950,09 Hz. Berdasarkan arah mendarat runway 05, OBS menunjukkan azimuth / bearing 191º sebagai panduan arah bandara tujuan, dengan frekuensi Efek Doppler antena sideband 112.209.960,049 Hz. Dan jenis gangguan frekuensi yang terjadi pada pengiriman sinyal frekuensi DVOR ke penerima (pesawat) adalah noise, fading, interferensi frekuensi radio

Uncertainty contribution of a wind turbine to the electric field of a DVOR antenna as a function of wind direction and rotor position

The presence of a wind turbine (WT) has the potential to distort electromagnetic fields emitted by terrestrial radio navigation aids. In this paper especially the field distortion of a Doppler Very High Frequency Omnidirectional Radio Range (DVOR) surveillance navigation system is investigated as a function of wind direction and rotor position. Therefor, the field distribution of a DVOR is simulated in the surrounding of a WT for 104 combinations of the angles of wind direction and rotor position. Furthermore, these calculations are executed for two different rotor diameters and 10 steps of distance between DVOR and WT in the range of 10 km. Based on the calculated data a method to estimate the maximum field distortion is developed. It is shown that the presented method allows to approximate the worst case field distortion with the results of two general simulation setups. Eliminating the need of simulating all possible geometric constellations of the WT this method hereby offers the benefit of significantly reduced simulation effort.DFGBMBF/FKZ/0325644A-

Analysis of biotic parameters of floodplain forests fragments in the agricultural landscape of the lower Váh river

We identify only fragments of the original floodplain forests on agricultural land in the alluvium of the lower Váh river. The reason of their elimination is based on the history, particularly because of agricultural land and hydrological modification of rivers. We evaluated biotic parameters of the floodplain forests fragments (life forms, diversity of vegetation, seasonality of leaves and flowering time) in the area of Calovec and Dulov Dvor. As for structural changes of vegetation in these areas, we can conclude that there was a difference in the range of species, in the Dulov Dvor locality hydrophilic population absent and invasive and potentially invasive species are more present (especially at Dulov Dvor locality). Analysis of biotic parameters of vegetation is part of a complete evaluation of fragments of floodplain forests (including abiotic parameters) aimed to restore their original function in the country

Analisis Link Budget Antena Sideband Doppler Very High Omni-Directional Range (DVOR) Pada Jalur Lintasan Penerbangan

Teknologi telekomunikasi terus berkembang seiring dengan perkembangan jaman. Mulai dari komunikasi kabel hingga komunikasi nirkabel. Salah satu pemanfaatan komunikasi nirkabel sebagai media komunikasi adalah teknologi radio yang diterapkan pada salah satu peralatan navigasi penerbangan, yang dikenal dengan istilah Doppler Very high Omni-Directional Range (DVOR). Dalam DVOR, informasi yang dikirim menggunakan efek doppler menuju pesawat akan  mengalami penurunan sinyal (loss) yang diakibatkan oleh jarak. Dengan melakukan analisis perhitungan link budget menggunakan parameter pathloss dan atenuasi terhadap efek doppler dengan objek penerima (pesawat), maka apabila pesawat semakin mendekat, akan menghasilkan Perubahan nilai pathloss dan atenuasi yang tidak berarti. Perhitungan pathloss dengan peubah jarak menghasilkan pengurangan ± 1dB pada rentang jarak tempuh pesawat, mulai dari jarak 30 Km hingga 5 Km dengan interval 5 Km. Sehingga semakin jauh jarak yang ditempuh oleh gelombang frekuensi Fobserved maka semakin besar nilai atenuasi yang akan diterima. Pada analisis atenuasi sebuah antena terhadap jangka waktu tertentu menghasilkan Perubahan sebesar ± 1dB dalam waktu tempuh dengan rentang masing-masing sebesar 32 detik, 29 detik, 26 detik, 22 detik, 18 detik, 15 detik, 12 detik, 10 detik, dan 8 detik, dan diperoleh kesimpulan semakin besar nilai waktu yang dipergunakan pada sebuah antena DVOR maka semakin kecil atenuasinya

Disturbing impact of multiple wind turbines on the indicated DVOR bearing

Radio navigation aids, like the Doppler Very High Frequency Omnidirectional Radio Range (DVOR), provide their navigation service by specific radiation of electromagnetic waves depending on the direction in space and according to their specific antenna characteristics. Therefore, these navigation aids are reliant on undisturbed wave propagation in their operation range. Certainly, a propagation disturbance can be implicated by the presence of scattering objects like large buildings or wind turbines (WT) in the surrounding area of the DVOR, which potentially leads to deviations of the transmitted navigation content. In order to comply with the specified flight safety limits, especially respecting WTs, there is a necessity to predict the prospective bearing error due to installations not only of individual WTs but also of additional ones in a present wind farm or repowering projects. Accordingly, this paper is aimed at ascertaining the bearing deviations' dependency on the quantity of WTs in a realistic wind farm close to a DVOR, calculated in space areas of practical relevance

“Unmapping” the Ural Playscapes: An Analysis of Playgrounds and Child Play under the Post-Soviet Urban Transition of Yekaterinburg, Russia

This study examines playgrounds as lenses on urban transitions to explain the link between urban transformations and changes in the discourse of play and childhood. Specifically, it compares Soviet public playgrounds and post-Soviet privatized playscapes in the city of Yekaterinburg, Russia, through primary observation and secondary data analysis. Using the framework of social reproduction developed by Cindy Katz and Saskia Sassen to explain how the local forces affect cities, my analysis shows that the shift in the discourse of play and childhood in the post-Soviet period is hinged on global influences combined with local transformations, from the abandonment of Soviet ideals of communal play spaces to the embracement of today’s consumerist play places. Whereas the old Soviet playgrounds have uncertain purposes, in contemporary Yekaterinburg private playgrounds offer a narrative of play in terms of leisure, love, and convenience for parents. Children turn into consumers of private play, leaving most of the Soviet playgrounds as idle spaces in the city. This article argues that Yekaterinburg’s shift toward participating in the globalized economy combined with its transition from the Soviet ideals maintains social relations and reproduces social inequalities in childhood, as this condition favors consumerist narratives of play. I conclude that the playgrounds in Yekaterinburg are bystanders of new global ecologies whereby social, political, and economic transformations become an impetus to reproduce new ways of seeing the social importance and meaning of play and playgrounds

Correlation between Voronoi volumes in disc packings

We measure the two-point correlation of free Voronoi volumes in binary disc packings, where the packing fraction $\phi_{\rm avg}$ ranges from 0.8175 to 0.8380. We observe short-ranged correlations over the whole range of $\phi_{\rm avg}$ and anti-correlations for $\phi_{\rm avg}>0.8277$. The spatial extent of the anti-correlation increases with $\phi_{\rm avg}$ while the position of the maximum of the anti-correlation and the extent of the positive correlation shrink with $\phi_{\rm avg}$. We conjecture that the onset of anti-correlation corresponds to dilatancy onset in this system

Dioklecijanov “carski dvor” u Duklji

The aim of the paper is the re-examination of the “forum” of late antique Doclea (Dioclea), the interpretation of which has never been finished, although so information been collated during the past 131 years. Through re-examination of the complex with its distinctive features this paper offers answers on some of the still unresolved issues. A primary is- sue was to resolve who was responsible for its arrangement. After an onomastic analysis only one conclusion asserted itself – the “forum complex” could only have been erected by the Emperor Diocletian, who was obviously responsible for the rearrangement of the whole town of Doclea (Dioclea), his hometown. Further analysis of the concept, architec- tural arrangement and vocabulary used in the “forum” and adjoining “basilica” only corroborate that it was precisely Diocletian and his “architectural school”. Without a doubt, the Doclean (Dioclean) “forum complex” was innovative and original in many ways, along with its importance as an “imperial forum”, the “Diocletian’s imperial court”, will re- main in the collective memory of the Montenegrins for centuries to come. The paper also represents an effort to clarify Diocletian’s background and the “modus operandi” of his “architectural school” whose presence in Doclea (Dioclea) has already been noticed.Cilj je rada preispitivanje kasnoantičkog “foruma” u Duklji, čija interpretacija, unatoč mnoštvu podataka prikupljenih tijekom proteklih 131 godinu, nikada nije dogotovljena. Rad nudi odgovore na pojedina neriješena pitanja proizašle upravo iz njegova preispitivanja. Prvenstveno pitanje bilo je vezano za naručitelja te gradnje. Po onomastičkoj analizi zaključak se sam nametnuo – “forumski sklop” mogao je dati podići isključivo sam car Dioklecijan, koji je, po svemu sudeći, bio zaslužan za uređenje i pregradnju svojega rodnoga grada. Analiza koncepta, specifičnog arhitektonskog rješenja i upotrijebljenog vokabulara samo je potvrdila prethodni zaključak. “Forumski kompleks” je nesumnjivo bio inovativan i originalan, a sjećanje na njega kao na “carski forum”, “Dioklecijanov carski dvor”, zadržao se u kolektivnom pamćenju Crnogoraca kroz dugi slijed stoljeća. Rad ujedno predstavlja nastojanje da se razjasni Dioklecijanovo podrijetlo i “modus operandi” njegove “arhitektonske škole” čija je prisutnost u Duklji već jasno zamijećena

Analisis Pengaruh Maintenance Terhadap Performance Peralatan Doppler Very High Frequency Omnidirectional Range (DVOR)

Studi sebelumnya atau studi terkait sangat penting dalam karya ilmiah atau penelitian. Karena belum terdapat pembahasan mengenai pengaruh maintenance terhadap performance peralatan DVOR, maka analisis ini diperlukan untuk mengetahui pengaruh maintenance terhadap performance peralatan DVOR. Dalam pelayanan navigasi penerbangan, peralatan DVOR harus dalam keadaan siap beroperasi, terpelihara serta terawat, maka diperlukan prosedur pemeliharaan (maintenance) dan pelaporan yang telah ditetapkan dalam SKEP 157 Tahun 2003 Tentang Pedoman Pemeliharan dan Pelaporan Peralatan Fasilitas Elektronika dan Listrik Penerbangan. Penelitian ini dilakukan dengan menggunakan metode kulitatif dan kajian literatur. Penelitian ini dapat menunjukkan bahwa maintenance memiliki hubungan dan berdampak pada performance peralatan untuk mencapai hasil yang optimal.In research or scientific work, previous research or related studies are essential. This investigation is required to ascertain the impact of maintenance on the performance of DVOR equipment because there hasn't been much debate regarding how maintenance affects DVOR equipment's performance. SKEP 157/IX/2003 concerning Guidelines for Maintenance and Reporting of Electronic and Electrical Aviation Facilities specifies maintenance procedures and reporting requirements for DVOR equipment in order for it to be used in aviation navigation services. The study's findings suggest that maintenance has an impact on how well the equipment works to produce desirable results