RAD Research and Education 2011

The annual report describes the main activities of the Department of Radio Science and Engineering (RAD) during the year 2011

Küp uydu anten sistemlerinin tasarım, benzetim ve üretimi

This study aims to design, simulate, and fabricate on-board and ground station antenna systems for CubeSats, i.e., the most affordable space missions. An on-board UHF turnstile antenna system is optimized in simulation evironment in accordance with different pattern requirements, by changing the orientation of the antenna arms. In order to feed the turnstile antenna arms by successive 90◦ phase differences between them, a four-way quadrature splitter circuit is designed and fabricated. Antenna pattern measurement is conducted in anechoic chamber by connecting the monopole antenna arms to the fabricated power splitter circuit, while the arms are oriented in the optimized directions and placed on a generic 1U CubeSat platform. In addition to the fabricated UHF turnstile antenna, a novel dual-band V/UHF trapped turnstile antenna involving traps on the antenna arms is designed in simulation environment. On the other side, a circularly polarized VHF ground station Yagi antenna system is designed to achieve optimum gain and size, and it is also fabricated by using low-cost materials to be employed for amateur radios. In addition to the radiating metal structure, the VHF Yagi antenna system includes a Wilkinson power divider and impedance matching baluns fabricated by coaxial transmission lines. Besides the reflection coefficient measurements, the constructed ground station antenna system is used for the reception of a Slow Scan TV (SSTV) image broadcasted by International Space Station (ISS) to test its functionality. Finally, as another component of a sub-GHz CubeSat ground station, a circularly polarized UHF Yagi antenna system is designed, based on the experience gained from the VHF ground station antenna design and measurement.Bu çalı¸smada, ula¸sması en kolay uzay platformları olan küp uydular için, araç üstü ve yer istasyonu antenlerinin tasarımı, benzetimi ve üretimi amaçlanmı¸stır. Araç üstü UHF turnike anten sistemi, farklı ı¸sıma örüntüsü gereksinimlerine göre, anten kollarının yönelimlerinin benzetim ortamında degi¸stirilmesiyle en iyile¸stirilmi¸stir. Turnike ˘ anten sistemi elemanlarının aralarında 90◦ faz farkları olacak ¸sekilde beslenmeleri için bir dört yollu, dördün-faz güç bölücü tasarlanmı¸s ve üretilmi¸stir. Üretilen güç bölücüye monopol anten elemanlarının en iyile¸stirilen yönelimlerle 1U ölçüsündeki bir CubeSat platformunun üzerindeyken takılmasıyla, ı¸sıma örüntüsü ölçümleri yankısız odada gerçekle¸stirilmi¸stir. Üretilen ve ölçümü gerçekle¸stirilen UHF bandındaki sistemden ba¸ska, anten kollarında tıkaçlar içeren yenilikçi bir çift-bant V/UHF tıkaçlı anten sistemi tasarlanmı¸stır. Diger tarafta, dairesel polarizasyonlu bir VHF yer istas- ˘ yonu Yagi anten sistemi, en uygun kazanç ve büyüklük hedefiyle tasarlanmı¸s, amatör telsiz kullanımları dogrultusunda dü¸sük bütçeli malzemelerden imal edilmi¸stir. Yayın ˘ yapan metal yapı, e¸s-eksenli iletim hatlarının kullanılmasıyla imal edilen Wilkinson güç bölücü ve empedans uyumlayıcı balunlar vasıtasıyla beslenmi¸stir. Yansıma katsavii yısı ölçümlerinin yanı sıra, Uluslararası Uzay ˙Istasyonu (ISS) tarafından yayınlanan yava¸s taramalı televizyon (SSTV) görüntüsünün üretilen anten yardımıyla alınmasıyla i¸slevsel testler gerçekle¸stirilmi¸stir. Son olarak, VHF anten tasarım ve ölçümlerinden elde edilen tecrübe ile, UHF frekans bandında çalı¸sacak bir Yagi yer istasyonu anten sistemi tasarlanmı¸stır.M.S. - Master of Scienc

スパースアレイ・レーダにおける信号処理技術

Tohoku University佐藤源之課

National Report for the IAG of the IUGG 2019-2022

Major results of researches conducted by Russian geodesists in 2019-2022 on the topics of the International Association of Geodesy (IAG) of the International Union of Geodesy and Geophysics (IUGG) are presented in this issue. This report is prepared by the Section of Geodesy of the National Geophysical Committee of Russia. In the report prepared for the XXVII General Assembly of IUGG (Germany, Berlin, 11-20 July 2023), the results of principal researches in geodesy, geodynamics, gravimetry, in the studies of geodetic reference frame creation and development, Earth's shape and gravity field, Earth's rotation, geodetic theory, its application and some other directions are briefly described. For some objective reasons not all results obtained by Russian scientists on the field of geodesy are included in the report.Comment: Misprint in the title of the arXiv record has been corrected. The submission content is not affecte

On the Use of High-Frequency Surface Wave Oceanographic Research Radars as Bistatic Single-Frequency Oblique Ionospheric Sounders

We demonstrate that bistatic reception of high-frequency oceanographic radars can be used as single-frequency oblique ionospheric sounders. We develop methods that are agnostic of the software-defined radio system to estimate the group range from the bistatic observations. The group range observations are used to estimate the virtual height and equivalent vertical frequency at the midpoint of the oblique propagation path. Uncertainty estimates of the virtual height and equivalent vertical frequency are presented. We apply this analysis to observations collected from two experiments run at two locations in different years, but utilizing similar software-defined radio data collection systems. In the first experiment, 10 d of data were collected in March 2016 at a site located in Maryland, USA, while the second experiment collected 20 d of data in October 2020 at a site located in South Carolina, USA. In both experiments, three Coastal Oceanographic Dynamics and Applications Radars (CODARs) located along the Virginia and North Carolina coast of the US were bistatically observed at 4.53718 MHz. The virtual height and equivalent virtual frequency were estimated in both experiments and compared with contemporaneous observations from a vertical incident digisonde-ionosonde at Wallops Island, VA, USA. We find good agreement between the oblique CODAR-derived and WP937 digisonde virtual heights. Variations in the virtual height from the CODAR observations and the digisonde are found to be nearly in phase with each other. We conclude from this investigation that observations of oceanographic radar can be used as single-frequency oblique incidence sounders. We discuss applications with respect to investigations of traveling ionospheric disturbances, studies of day-to-day ionospheric variability, and using these observations in data assimilation

Geodeettinen pitkäkantamainterferometria ja Tohokun maanjäristyksen vaikutukset - Tsukuban aseman tapaustutkimus

Very Long Baseline Interferometry (VLBI) observations can be used to analyse VLBI station coordinates and Earth Orientation Parameters (EOP). The goal of this thesis is to utilize Matlab-based Vierma VLBI Software (Vie VS) to study the effects of the March 11th, 2011 earthquake in Japan at the Tsukuba VLBI station. Both IVS 24-hour and 1-hour intensive sessions are used in the analysis. At first, each session is pre-processed individually and the station wise residuals are inspected to remove possible sources of error, such as clock breaks at one or more of the observing stations. After the initial processing is complete, the sessions are analysed to compute geodetic parameters. A total of 31 24-hour and 40 intensive sessions, which contain measurements from Tsukuba, are used in the final analysis. The 24-hour sessions are used to compute the initial displacement and post seismic drift of the station coordinates. The initial displacement of the station derived from the analysed VLBI observations was (65.48, 1.88, -7.38) cm in the local East-North-Up reference frame. The post seismic movement is modelled by fitting a transient decay model to the observation data. The continuous fit is used to obtain corrected a priori coordinates for the intensive sessions. The results are validated by the improved dUTI estimates from both 24-hour and intensive sessions. The mean formal errors decreased for both 24-hour and intensive sessions. For 24-hour sessions the mean formal error reduced approximately 30 %. The improvement is most evident in the IVS-INT2 intensive sessions, which include only one baseline, of which Tsukuba is the other station. For these sessions the mean formal errors reduced by five orders of magnitude. Additionally, the results were inspected by comparing the data with third party VLBI and GPS results. The computed results agree at worst within a few centimetres with the comparison data.Pitkäkantamainterferometrialla (VLBI) voidaan havainnoida sekä maapallon orientaatioparametreja (EOP) että VLBI-asemien koordinaatteja. Tämän diplomityön tavoitteena on tutkia Japanissa 11. maaliskuuta 2011 tapahtuneen maanjäristyksen vaikutuksia Tsukuban VLBI-asemaan käyttämällä Matlab-pohjaista VLBI-analysointiohjelmistoa VieVSia (Vienna VLBI Software). Tutkimuksessa käytetään kahdenlaisia havaintosessioita: vuorokauden mittaisia sekä tunnin kestoisia intensiivisessioita. Aluksi kaikki 24 tunnin VLBI-havainnot esikäsiteltiin yksitellen VieVSillä, jotta mahdolliset virhelähteet saadaan eliminoitua. Merkittävin yksittäinen virhelähde ovat hypyt asemien kelloissa. Kun havaintosessiot on esikäsitelty, niiden avulla lasketaan havaintomalliin liittyvät geodeettiset parametrit. Lopullisessa analyysissä käytettiin yhteensä 31 24 tunnin sessiota ja 40 intensiivissessiota, joista molemmissa havaintotyypeissä jokaisessa sessiossa on mukana Tsukuban VLBI-asema. 24 tunnin sessioita käyttäen selvitetään havaittu välitön siirtymä aseman koordinaateissa. Paikallisessa toposentrisessä järjestelmässä (Itä-Pohjoinen-Ylös) antenni siirtyi (65.48, 1.88, -7.38) cm. Maanjäristyksen jälkeisiin havaittuihin aseman koordinaatteihin sovitetaan vaimentuva eksponentiaalinen malli, jonka avulla saadaan jatkuva estimaatti aseman koordinaateille. Intensiivisessiot käsitellään uudestaan tästä mallista saaduilla a priori asemakoordinaateilla. 24 tunnin sessioista saadut estimaatit voidaan vahvistaa tutkimalla dUTI-orientaatioparametrissa tapahtuvaa parannusta. Sekä vuorokauden mittaisten että intensiivisessioiden keskimääräinen keskihajonta pieneni. 24 tunnin sessioilla parannus oli noin 30 %. Parhaiten korjattujen a priori koordinaattien vaikutus näkyi niissä intensiivisessioissa, jotka havainnoitiin ainoastaan Tsukuban ja toisen aseman välillä. Näissä sessioissa keskivirheet pienenivät viisi kertaluokkaa. Havaintojen sisäisen tarkastelun lisäksi saatuja tuloksia verrattiin ulkopuoliseen VLBI- ja GPS-dataan. Tulokset olivat huonoimmillaankin yhteneviä muutaman senttimetrin tarkkuudella

Proceedings of the Eleventh U.S.-Japan Meeting on Aquaculture, Salmon Enhancement, Tokyo, Japan, October 19-20, 1982

The United States and Japanese counterpart panels on aquaculture were formed in 1969 under the United States-Japan Cooperative Program in Natural Resources (UJNR). The panels currently include specialists drawn from the federal departments most concerned with aquaculture. Charged with exploring and developing bilateral cooperation, the panels have focused their efforts on exchanging information related to aquaculture which could be of benefit to both countries. The UJNR was started by a proposal made during the Third Cabinet-Level Meeting of the Joint United States-Japan Committee on Trade and Economic Affairs in January 1964. In addition to aquaculture, current subjects in the program are desalination of seawater, toxic microorganisms, air pollution, energy, forage crops, national park management, mycoplasmosis, wind and seismic effects, protein resources, forestry, and several joint panels and committees in marine resources research, development, and utilization. Accomplishments include: Increased communications and cooperation among technical specialists; exchanges of information, data, and research findings; annual meetings of the panels, a policy coordinative body; administrative staff meetings; exchanges of equipment, materials, and samples; several major technical conferences; and beneficial effects on international relations. (PDF file contains 108 pages.

Faculty Publications and Creative Works 1999

One of the ways in which we recognize our faculty at the University of New Mexico is through Faculty Publications & Creative Works. An annual publication, it highlights our faculty\u27s scholarly and creative activities and achievements and serves as a compendium of UNM faculty efforts during the 1999 calendar year. Faculty Publications & Creative Works strives to illustrate the depth and breadth of research activities performed throughout our University\u27s laboratories, studios and classrooms. We believe that the communication of individual research is a significant method of sharing concepts and thoughts and ultimately inspiring the birth of new ideas. In support of this, UNM faculty during 1999 produced over 2,292 works, including 1,837 scholarly papers and articles, 78 books, 82 book chapters, 175 reviews, 113 creative works and 7 patented works. We are proud of the accomplishments of our faculty which are in part reflected in this book, which illustrates the diversity of intellectual pursuits in support of research and education at the University of New Mexico