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Within-Field Mapping of Winter Wheat Biophysical Variables Using Multispectral Images from UAV 基于无人机多光谱影像的冬小麦生物物理变量田内制图
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e02
G. Jelev, P. Dimitrov, E. Roumenina
{"title":"Within-Field Mapping of Winter Wheat Biophysical Variables Using Multispectral Images from UAV","authors":"G. Jelev, P. Dimitrov, E. Roumenina","doi":"10.3897/arb.v34.e02","DOIUrl":"https://doi.org/10.3897/arb.v34.e02","url":null,"abstract":"The paper presents the results from a study aiming to map the dynamic of biophysical variables of winter wheat crops in different phenological growth stages (PGSs) using multispectral camera data acquired by Unmanned Aerial Vehicle (UAV). The studied biophysical variables are Leaf Area Index (LAI), fraction of Absorbed Photosynthetically Active Radiation (fAPAR) and fraction of vegetation cover (fCover). During agricultural year 2016/2017, 4 field campaigns (FCs) were carried out in 6 farmer-managed fields sown with two winter wheat varieties. During the FCs, 8 UAV flight missions were accomplished. Linear and exponential regression models were designed and evaluated to derive predictive equations for the biophysical variables of the crops based on a set of vegetation indices (VIs). The best predictor for all biophysical variables was OSAVI (RMSE was 0.90 m2/ m2, 0.07 and 0.08 for LAI, fAPAR, and fCover respectively). The chosen models were used to compose maps of LAI, fAPAR, and fCover of the studied fields. The maps correspond well with the spatial distribution of the values of the respective biophysical variables measured during the respective field campaign.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394268","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}
引用次数: 1
Polarimetric Analysis of ALOS PALSAR data (POL-SAR) over Test Areas in North-West Bulgaria – Polarimetric Descriptors, Decompositions and Classifications 保加利亚西北部试验区ALOS PALSAR数据(POL-SAR)的极化分析——极化描述符、分解和分类
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e03
Zlatomir Dimitrov
{"title":"Polarimetric Analysis of ALOS PALSAR data (POL-SAR) over Test Areas in North-West Bulgaria – Polarimetric Descriptors, Decompositions and Classifications","authors":"Zlatomir Dimitrov","doi":"10.3897/arb.v34.e03","DOIUrl":"https://doi.org/10.3897/arb.v34.e03","url":null,"abstract":"This study is focused on utilizing full-polarimetric L-band radar data from ALOS PALSAR (JAXA) by means of Polarimetry (POL-SAR), over mountainous test sites in Bulgaria. General aim is to show feasibility of the Polarimetry to describe natural targets, which exhibits various scattering mechanisms in respect to their bio-physical and geometrical properties. Firstly, the importance of Covariance and Coherent matrices is shown, which is followed by calculation of the polarimetric coherences with their particular significance. The mathematical and physical model based decompositions are applied to describe backscattering media from scattering mechanisms. Radar indices resulted from H/A/α-decomposition showed radnomization of scattering mechanisms over forest areas, whilst two major scattering mechanisms are observed mainly in crop lands. Α comparison is made between polarimetric descriptors from acquisitions in different seasonality over mountainous forest and agricultural lands. Polarimetric segmentations and classifications are applied, with 8 (H/A) and 16 (H/A/α) components. Finally, a forest mask is proposed based on relevant polarimetric descriptors. Study showed good utilization and importance of the full-polarimetric L-band SAR data, derived from ALOS PALSAR, in natural targets and forest areas. This report resulted from a course GEO414 -“Polarimetrie”, held at the University of Jena, Lehrstuhl für Fernerkundung, in the framework of ERASMUS+, with the kind support of – Dr. T. Jagdhuber (DLR) and Prof. C. Schmullius.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394305","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}
引用次数: 0
Design of a Flap for Straight Wing of Unmanned Aerial Vehicle 无人机直翼襟翼设计
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e06
K. Metodiev
{"title":"Design of a Flap for Straight Wing of Unmanned Aerial Vehicle","authors":"K. Metodiev","doi":"10.3897/arb.v34.e06","DOIUrl":"https://doi.org/10.3897/arb.v34.e06","url":null,"abstract":"In the paper hereby, design of a single stage Fowler flap is proposed. The flap is meant to increase lifting abilities of a straight wing at low speeds. It is applicable to small-sized remotely controlled unmanned aerial vehicles widely available to hobbyists. The design process included thorough analysis of flow around a wing foil in case of both retracted and deployed flap. To obtain aerodynamic coefficients values at different angles of attack and Reynolds numbers was a primary goal. In addition, a linkage mechanism was developed to make it possible for the flap to move along a complex path. Various plots and charts are depicted thereafter with sole purpose of providing better understanding of the idea.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394352","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}
引用次数: 0
Challenges in International Research on Celestial Bodies. The Prospects of the Bulgarian Space Policy 国际天体研究面临的挑战。保加利亚空间政策的前景
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e17
A. Milanov
{"title":"Challenges in International Research on Celestial Bodies. The Prospects of the Bulgarian Space Policy","authors":"A. Milanov","doi":"10.3897/arb.v34.e17","DOIUrl":"https://doi.org/10.3897/arb.v34.e17","url":null,"abstract":"The article explores the present political challenges in international research and exploration of states and private actors of celestial bodies. The lack of shared vision of what type of space activities should be planned and the principles of creating research facilities and scientific missions on the Moon and other celestial bodies is causing uncertainty in future space missions and increases the possibility for a military conflict. The political alliances that exclude specific states will increase the risk of a generation of unnecessary space debris and space waste on celestial bodies. This dangerous outcome could be prevented by agreeing on a shared vision of exploitation and exploration of celestial bodies that preserve the outer space environment and adopting comprehensive guidelines for space activities accepted by the leading space-faring nations.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394081","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}
引用次数: 1
Inventor and Innovative Work at the Space Research and Technology Institute – Bulgarian Academy of Sciences 保加利亚科学院空间研究和技术研究所的发明者和创新工作
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e16
G. Jelev
{"title":"Inventor and Innovative Work at the Space Research and Technology Institute – Bulgarian Academy of Sciences","authors":"G. Jelev","doi":"10.3897/arb.v34.e16","DOIUrl":"https://doi.org/10.3897/arb.v34.e16","url":null,"abstract":"The current article attempts to present the created inventions at the Space Research and Technology Institute – Bulgarian Academy of Sciences during the last 40 years. In view of this long period of time, there exist patents and awards that were omitted from mentioning. The current paper elaborates on the different types of patent and utility model documents that were issued from Bulgarian Patent Office and other foreign patent offices where Space Research and Technology Institute – Bulgarian Academy of Sciences has registered their inventions. A list of recent awards from local and international forums for inventors has been shown. Mentioned were some of the prominent inventors who worked at the Institute. Finally, the article concludes the need for development of specialized information system to store the patent documents of the Institute and to deliver to the public comfortable means of thorough, detailed and quick inquiries.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394042","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}
引用次数: 0
Identifying Batch Problems in Aircraft Field Reliability Analysis 飞机现场可靠性分析中的批量问题识别
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e11
Kolyo Kolev, A. Tanev
{"title":"Identifying Batch Problems in Aircraft Field Reliability Analysis","authors":"Kolyo Kolev, A. Tanev","doi":"10.3897/arb.v34.e11","DOIUrl":"https://doi.org/10.3897/arb.v34.e11","url":null,"abstract":"In practice, a very important task is to monitor the field reliability of aircraft systems, especially the ones related to aviation safety, and to take relevant actions to prevent from potential consequences. Zooming in that task, one can state that a very important step in that analysis is to identify batch problems where the failure mode only affects a subset of the fleet. The Weibull distribution typically provides the best fit of life data obtained either from test or from field. This is due in part to the broad range of distribution shapes that are included in the Weibull family. As well as, there are many other distributions which are included in the Weibull distribution’s family either exactly or approximately- for example, the normal, the exponential, the Rayleigh, and sometimes the Poisson and the Binomial. This paper presents a practical approach for those aviation professionals dealing with monitoring and analyzing the aircraft field reliability.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"35 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393935","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}
引用次数: 0
Systems for Secondary Electric Power Supply of the Instruments "Zora" and "Neurolab-B" – Space Medicine 空间医学仪器“Zora”和“Neurolab-B”的二次供电系统
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e10
P. Gramatikov, R. Nedkov, Raicho Todorov
{"title":"Systems for Secondary Electric Power Supply of the Instruments \"Zora\" and \"Neurolab-B\" – Space Medicine","authors":"P. Gramatikov, R. Nedkov, Raicho Todorov","doi":"10.3897/arb.v34.e10","DOIUrl":"https://doi.org/10.3897/arb.v34.e10","url":null,"abstract":"The \"Zora\" and \"Neurolab-B\" instruments solved problems related to the study, control and prediction of astronaut health. The \"Zora\" instrument is a computer system for collecting and processing data from complex neurophysiological experiments: \"Statokinetiks\"; \"Labyrinth\"; \"Potential\"; \"Leisure Time\"; \"Questionary\", etc. The system for complex research of the psychophysiological state of astronauts \"Neurolab-B\" is used for scientific experiments with the help of a number of international crews. Engineering solutions are proposed according to the investigated specificity of the powered devices. Both systems have been operating on board the Mir space station – \"Neurolab-B\" from 1996 to 2000. New space medicine instruments used on the Russian sector of the international space station are considered. Since 2000, four new secondary power systems for space instruments have been developed at the Institute of Space Research and Technology – Bulgarian Academy of Sciences. They are applicable in both space physics and space medicine.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70393930","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}
引用次数: 0
Dependence of the Gleisberg Cycle Period on the Length of Wolf's Numbers Series Gleisberg周期对Wolf数序列长度的依赖性
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e01
I. Shibaev, Aleksandr Shibaev
{"title":"Dependence of the Gleisberg Cycle Period on the Length of Wolf's Numbers Series","authors":"I. Shibaev, Aleksandr Shibaev","doi":"10.3897/arb.v34.e01","DOIUrl":"https://doi.org/10.3897/arb.v34.e01","url":null,"abstract":"The concept of \"Gleisberg cycle\" arose from the analysis of a small amount of data for a series of Wolf numbers (WSN), which are characterized by varying degrees of reliability and with the key role of cycles 5-7 of the Dalton minimum. Back in the thirties of the last century, when analyzing the first 16 cycles was done, Gleisberg noted the frequency of their maximums in seven to eight cycles, and later gave an updated value of the period - about 80 years. In the works done over the past 60 years, this period is evaluated within 80 - 110 years. A number of researchers allocate a specific value for the Gleisberg cycle period equals to 88 years. Since different authors analyzed a series of Wolf numbers of different lengths, it makes sense to investigate the influence of the length of the series itself on this period. The paper analyzes the long-period components of WSN versions v1 and v2. The connection between the period and the length of the series is found through the sine approximation of the corresponding fragments. An increase in the sine period from 82 to 110 years (for v1) was obtained with an increase in the length of the series from 18 to 24 cycles and the conditions for the local manifestation of the 88-year harmonic. The initial periodicity of the maximums of seven to eight cycles is transformed into ten to eleven cycles. The WSN series includes recovered data from 1749 to 1849 and further on, regular observation data - reliable data. The dependence of the period on the length of the series, that is, on the share of reliable data, is associated with the inconsistency of the characteristics of the reconstructed and reliable series and casts doubt on the existence of the Gleisberg cycle or “secular” harmonic in the WSN readings in the 1749-2015 interval. changes in the land cover by temporal analysis.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"35 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394264","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}
引用次数: 0
Aerospace Systems "Aerial Launch" at the Modern Stage 现代阶段的航空航天系统“空中发射”
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e07
Pavel Penev, Nikolay Zagorski
{"title":"Aerospace Systems \"Aerial Launch\" at the Modern Stage","authors":"Pavel Penev, Nikolay Zagorski","doi":"10.3897/arb.v34.e07","DOIUrl":"https://doi.org/10.3897/arb.v34.e07","url":null,"abstract":"The need for the emergence and use of aerospace systems (ASS) \"Aerial launch\" by the leading countries has been formulated. The types of ASS and the types of military space systems are revealed, as well as the connection between them. The functioning and perspective ASS \"Aerial launch\" with civil and military applications is analyzed. Based on a systematic analysis, a structure of ASS \"Aerial launch\" for the conditions of the Republic of Bulgaria, its advantages, disadvantages and main properties is proposed. Based on the performed modeling, a scheme of operation of ASS \"Aerial launch\" and stages of the flight of the MiG-29UB carrier aircraft for launching a nanosatellite (nanosatellites) into orbit in the conditions of our country is proposed.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394362","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}
引用次数: 0
Digital Signal Processing in RadioSolariz Project Using SSE2 RadioSolariz项目中使用SSE2的数字信号处理
IF 0.3
Aerospace Research in Bulgaria Pub Date : 2022-01-01 DOI: 10.3897/arb.v34.e05
S. Zabunov
{"title":"Digital Signal Processing in RadioSolariz Project Using SSE2","authors":"S. Zabunov","doi":"10.3897/arb.v34.e05","DOIUrl":"https://doi.org/10.3897/arb.v34.e05","url":null,"abstract":"This paper aims at elaborating on the digital signal processing techniques used in data manipulation in the radioSolariz solar radio-telescope project. Focus is drawn on the implementation of different digital signal processing algorithms through the use of streaming single instruction – multiple data extensions 2. This complementary instruction set to general purpose personal computer microprocessors offers increased computational power by realizing parallel processing. The benefit is a higher data throughput while lowering the electrical power consumption of the digital signal processing computer. Optimized code fragments are shown along with original code snippets and these are discussed and analyzed. Future work and implementation of other modern parallel processing technologies are envisaged.","PeriodicalId":40457,"journal":{"name":"Aerospace Research in Bulgaria","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70394321","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}
引用次数: 0
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