Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.最新文献

{"title":"Belief propagation decoding of some decomposable linear block codes","authors":"G. Altay, S. Yalçin","doi":"10.1109/RAST.2005.1512613","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512613","url":null,"abstract":"We implement the belief propagation algorithm onto some decomposable linear block codes and obtain bit error rate performances for some of the decomposable codes over additive white Gaussian noise channel. A comparison between the belief propagation algorithm and the Viterbi algorithm is also performed with respect to the obtained error performances.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129653049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GOLGE: a case study of a secure data communication subsystem for micro-satellites","authors":"S. Yesil, R. Sever, B. Okcan, N. Ismailoglu","doi":"10.1109/RAST.2005.1512607","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512607","url":null,"abstract":"This paper presents a real-time data encryption/decryption subsystem developed for a satellite, which is planned to be launched in 2007 by TUBITAK-BILTEN. The subsystem GOLGE contains two ASICs, which perform encryption/decryption using AES (Advanced Encryption Standard) and RSA (Rivest-Shamir-Adleman) algorithms and a communication interface unit. The data/command interface of the GOLGE module is implemented on a reconfigurable ASIC (FPGA), where the encryption/decryption processors have previously been designed in TUBITAK-BILTEN and prototyped in ANTIS 0.35-/spl mu/m CMOS technology. The system uses an 8-bit bidirectional data bus, which operates at a maximum frequency of 40 MHz supplying a throughput of 160 Mbit/sec and a SpaceWire interface, which provides a 100 Mbit/sec serial data communication link.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129498926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and application of bonding agents used in rocket propellants","authors":"D. Dundar, M. Gullu, M. Ak, G. Puskulcu, C. Yildirim","doi":"10.1109/RAST.2005.1512587","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512587","url":null,"abstract":"In this research work, utilisation of new bonding agents, synthesised from cheap and easily available starting materials, have been investigated in composite rocket propellants and liners in place of widely used aziridine and amine based bonding agents (MAPO, HX-752, TEPANOL). The performance properties of propellants and liners prepared with these compounds have been examined. Some simple alkyl hydantoins (AH1, AH2, AH3) and their N-alkyl and N,N-dialkyl derivatives (HT1, HT2, HT3, HT4, HT5) have been synthesised in laboratory scale and structurally identified in the first step. Later, some of the selected hydantoin derivates have been used as bonding agents in the preparation of propellants and liners. Twelve propellant samples and eight liner samples have been subjected to some physical and mechanical tests which are generally used for the examination of rocket propellants and liners. Most of the propellants and liners have shown good physical and mechanical performance properties, except ones which were prepared with hydantoins containing morpholino groups. In addition physical and mechanical tests, some of the propellants have been used in Ballistic Research Motor (BRM) tests and shown perfect results.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128882183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of a multi-stage bogie suspension system to the planet exploration vehicles","authors":"O. Kilit","doi":"10.1109/RAST.2005.1512581","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512581","url":null,"abstract":"To design more and more dynamically stable vehicles to be able to use in exploration tasks in rough terrain environment of solar system planets is extremely important because of the difficulties in manipulating the vehicle from a long distance. In this study the application of innovative multi-stage bogie suspension system to a rough terrain vehicle and effects of changing the parameters of this suspension system on vehicle's stability has been Investigated. Firstly mathematical model of rough terrain has been created. In this model rough terrain is thought as an interpolated spline in which the obstacles are assumed as control points. Then an off-road vehicle with a new type of a bogie suspension system has been represented. It has been shown that, increasing the number of the stages of bogie mechanism results in a more stable vehicle when moving on a rough terrain. To eliminate the effects of inertia forces, vehicle is assumed as quasi-static. Solution of this analysis has been given as computer generated simulation and graphics.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"60 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120838733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring and evaluation of the vegetation state of agricultural crops using satellite - derived radiative products","authors":"A. Nertan, G. Stancalie, A. Iordache, S. Catana","doi":"10.1109/RAST.2005.1512619","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512619","url":null,"abstract":"The topic of the paper focuses on satellite remotely sensed monitoring of the Earth surface and, in particular, of the vegetation. The main task of the study is to model the vegetation reflected field in the visible and near infrared spectral domains, based on ground measurements and simulated data, gathered in different natural conditions, as well as on satellite data. The paper tries to establish connections between the biophysical parameters of a vegetation canopy, the reflected radiation flux in different spectral channels and the geometrical and radiometrical factors that characterize the interaction processes in the atmosphere-vegetation-soil system. The vegetation reflectance model, used in the study, is based on the radiative transfer theory and on the concepts developed by the turbid models. The model uses the approximation of four radiative flows (diffuse upwards and downwards flows and direct upwards and downwards flows) expressed by linear differential equations in order to evaluate the radiative flow in any point on a vegetation cover. This model computes the bidirectional reflectances as a function of the optical proprieties of the vegetative elements (especially the leaves), such as the factors that define the architecture of vegetation: density, orientation and spatial distribution of these elements. The algorithm takes into consideration the illumination conditions and the parameters associated with the geometry of observations. The model estimates the reflectances of vegetation in the visible and near infrared channels, operated by some of the most used operational satellite sensors: SPOT, LANDSAT - TM, NOAA - AVHRR, TERRA - MODIS, TERRA - ASTER, etc. The paper presents the derived radiative products, like vegetation indices, spectral signature characteristics, moisture or thermal stress indices issues from the model and the application for the vegetation state monitoring of the main agricultural crops in the Romanian Plain, situated in the South part of the territory. The benefits of the practical use of the radiative products in studies of the vegetation development dynamics or for determining the vegetation state criteria and the biological potential are also emphasized.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121097444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ground testing of a liquid fueled rocket motor","authors":"G. Puskulcu, B. Sumer, D.E. Gunduz, C. Yildirim, C. Yazici, F. Orhan, L. O. Gonc, M. Ak","doi":"10.1109/RAST.2005.1512584","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512584","url":null,"abstract":"In a research project carried by TUBITAK-SAGE, Turkey's first operational liquid fuelled rocket motor has been designed, manufactured and tested. The rocket motor uses hydrogen peroxide as oxidizer and hydrocarbon based chemical as fuel. Also some metal salts are added into the fuel in order to attain hypergolic ignition. The fuel and oxidizer are fed into the system by using high pressure nitrogen gas. The control of pressurized fuel and oxidizer into the motor combustion chamber is achieved by using pressure operated valves and a control card. Mass flow rates of oxidizer and fuel are controlled by using cavitating venturis. In order to improve the combustion performance, an unlike triple impinging type injector is used to spray the fuel and injector into the combustion chamber. Before the testing of the liquid propellant rocket motor (LPRM) system, some simplified tests were performed on subsystems. These tests include flow rate check tests, hypergolic ignition tests and flow tinting tests. This paper contains the detailed explanation of the liquid propellant rocket motor system that has been ground tested, and the results of the tests performed. The ground tests were performed at the static test ramp, at TUBITAK-SAGE, Ankara. In the first motor test no data is taken and the general characteristic of the rocket motor is observed by using normal speed and high-speed cameras. In later tests two pressure transducers is mounted on the rocket liquid propellant rocket motor (LPRM) System. The first transducer is mounted to the rocket motor body to measure the combustion chamber pressure and the second one is mounted at the exit of the cavitating venturi. The rocket motor aluminum case is instrumented with three strain gages and two temperature sensors. A third temperature sensor is also placed at the nozzle exit to measure the nozzle exit gas temperature.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126565562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inter-satellite optical communication networks: RF fading diversity for higher spectral efficiency","authors":"A. Sahin, S. Kurnaz","doi":"10.1109/RAST.2005.1512612","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512612","url":null,"abstract":"Revolutionary developments in semiconductors lead to efficient deployment of lasers and photodetectors, thus enabling optical transmission of data signals, whether in fiber optic links or free space. Line of sight transmission characteristic of optics ensures the security of the data. With the incessant increase in the numbers of satellites and the data payload required to handle, it is inevitable that in the future we will see a shift towards optical networking, especially in the earth orbiting satellites. We demonstrate a novel all-optical multiplexing technique for doubling the usable spectral bandwidth and number of channels in subcarrier-modulated data transmission over free-space optical connections. By taking advantage of the chromatic-dispersion-induced RF power fading of a given subcarrier frequency, we can transmit two subcarrier channels that occupy the same frequency space.. We successfully transmit and receive two 155 Mbit/s data channels that are both located at 7.1 GHz.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126586256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geo-information, Earth observation, and their role for society","authors":"W. Kainz","doi":"10.1109/RAST.2005.1512539","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512539","url":null,"abstract":"We live in an information society. A large amount of all the information used today is referenced to a location in space and time. Geo-information is derived from various types of data acquired by means of Earth observation systems, surveying, photogrammetry, digitization, and other analog or digital sources. In this paper a general framework of spatial data handling with its organizational, societal, and cultural background is presented. We give a description of the technological developments, the mechanisms and procedures that determine the context of Earth observation and spatial data handling as well as their implications on society.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126638176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of snow cover extent in Carpathian Mountains using integrated GIS and remote sensing information","authors":"C. Flueraru, G. Stancalie, S. Catana, E. Savin, Anisoara Irimescu","doi":"10.1109/RAST.2005.1512632","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512632","url":null,"abstract":"The alpine snow cover in the mid-latitudes is important in risk management, climatic and hydrologic context. An accurate mapping of snow cover and estimation of snow characteristics requires snow to be distinguished from other surface cover and from clouds. In order to become useful, this information about snow extent, have to be provided on regular bases for various types of users. This study was carried out on a test area located in the central part of Romania - the upper part of Arges basin and Vidraru reservoir. The available information (Landsat ETM+ derived land cover and a 15m digital elevation model) were integrated with the MODIS MYD10A1 daily snow cover products (snow extent & albedo) using a 10m cell grid. Snow was classified in various classes of confidence using additional information such as vegetation cover, vegetation type, slope, aspect etc. This information is being used as input for the determination of the water supply available for the major reservoirs from the winter snow pack. This will allow also, in the very next future, the estimation of avalanche risk-areas as well as the dynamics of the snow cover extent during 2004 - 2005 winter season for different types of land cover. In the same time a four months validation of the MODIS products was carried out using information from the meteorological station network and on-field observation.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127048509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modification of electron density profile about the earthquake epicenter by GPS data","authors":"E. Smirnova, V. Smirnov","doi":"10.1109/RAST.2005.1512669","DOIUrl":"https://doi.org/10.1109/RAST.2005.1512669","url":null,"abstract":"For testing the hypothesis about the modification of an ionosphere F2-layer in the epicenter area several days before the earthquake which occurred on August 17, 1999 in Turkey, the data from the stations removed from seismic zone were processed. IGS station coordinates: ZECK - 43.79N, 41.57 W; ZWEN 55.7 N, 36.76 W. The ionosphere state analysis was carried out during on August 13-18. The electronic concentration profile and its maximal meaning in a F2-layer were considered. The variations of an electronic plasma maximum were received by radio translucence method on the GPS satellite, observable simultaneously with stations ANKR, ZECK and ZWEN. For definition of high-altitude structures of an ionosphere the standard RINEX-files of observations introduced on a site http://garner.ucsd.edu/pub were used.","PeriodicalId":156704,"journal":{"name":"Proceedings of 2nd International Conference on Recent Advances in Space Technologies, 2005. RAST 2005.","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127010121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}