Satellite Links
Mostrando 1-12 de 17 artigos, teses e dissertações.
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1. Assessment of Total Attenuation and Adaptive Scheme for Quality of Service Enhancement in Tropical Weather for Satellite Networks and 5G Applications in Nigeria
Abstract The dynamic weather condition is a major concern for optimum channel utilization in recent times, especially at higher frequencies with larger bandwidth for 5G applications. Over the years, rain-induced attenuation among the hydrometeors has been linked as the major cause of signal impairment especially at the frequency, f ≥ 10 GHz. However, when
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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2. Interaction Between Motions of Robotic Manipulator arms and the Non-Fixed base in On-Orbit Operations
ABSTRACT: The objective of this paper is to study the problem of the robotic manipulator operating on a non-fixed base by considering two dynamics scenarios. One in which the base is free to react in response to the robotic manipulator motion and the other in which the robotic manipulator moves its links in such a way to compensate the reaction forces on the
J. Aerosp. Technol. Manag.. Publicado em: 2015-12
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3. Radio-Wave Propagation Model for UHF Band in Different Climatic Conditions with Dyadic Green’s Function
AbstractThis article proposes a deterministic radio propagation model using dyadic Green's function to predict the value of the electric field. Dyadic is offered as an efficient mathematical tool which has symbolic simplicity and robustness, as well as taking account of the anisotropy of the medium. The proposed model is an important contribution for the UHF
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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4. Unified method for the prediction of rain attenuation in satellite and terrestrial links
In this paper, a semi-empirical method for the prediction of rain attenuation in slant paths and terrestrial links is proposed. The method uses the same simplified model of equivalent rain cell that is the basis for the ITU-R rain attenuation prediction methods but, additionally, the concept of an effective rain rate is introduced. This allows the use of the
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06
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5. EFFECT OF MOVING PLATFORMS ANTENNA POINTING ERRORS ON THE PERFORMANCE OF DIGITAL SATELLITE LINKS / EFEITO DO ERRO DE APONTAMENTO DE ANTENAS FIXADAS EM PLATAFORMAS MÓVEIS NO DESEMPENHO DE SISTEMAS DE COMUNICAÇÃO DIGITAL POR SATÉITE
O dimensionamento de enlaces digitais de comunicação e realizado com base em objetivos de desempenho a serem satisfeitos por determina- dos parâmetros, considerando o comportamento aleatório das fontes de degradação do sinal. Em sistemas de comunicação móvel por satélite, o de- sempenho pode ser fortemente afetado pelo erro de apontamento da antena
Publicado em: 2011
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6. Análise de discurso crítica e etnografia : o movimento nacional de meninos e meninas de rua, sua crise e o protagonismo juvenil
This thesis is the result of a research study aimed at investigating the crisis in the National Street Childrens Movement in the Federal District. This crisis as well as its consequences on juvenile protagonism, the Movements main focus, were proven empirically and confirmed in ethnographic data. In conducting this study, ethnographic methods were used to ge
Publicado em: 2008
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7. Dynamic loading and linking native code on a real-time operating system.
This thesis presents a very efficient and simple approach to native code generation and dynamic code loading for the RTOS RTEMS on the Blackfin architecture. The whole solution is intended for PLCs implementing the IEC 61131-3 standard. The second part of the solution, native code loading on RTEMS, is also usable for code updates in satellite applications. F
Publicado em: 2007
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8. Análise de Desempenho de Redes TCP sem Fio / Performance analysis of wireless TCP networks
The TCP/IP networks were designed considering the use of wired media. Although, the huge growth of the Internet together with the growth of the wireless transmissions caused the need of insertion of TCP in this new scenario. As some of the wireless networks characteristics are harmful to the standard TCP, as the higher bit error rates, the intermittent signa
Publicado em: 2006
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9. A SEMI-EMPIRIC CONSISTENT MODEL FOR RAIN ATTENUATION PREDICTION IN TERRESTRIAL AND SATELLITE RADIO LINKS / PREVISÃO DA ATENUAÇÃO POR CHUVAS ATRAVÉS DE UMA MODELAGEM SEMI-EMPÍRICA CONSISTENTE PARA ENLACES RÁDIO TERRESTRE E VIA SATÉLITE
Com a crescente utilização de sistemas de acesso sem fio ponto-multiponto em banda larga, operando em freqüências cada vez mais elevadas, cresce também a necessidade do desenvolvimento de novos modelos, mais precisos e consistentes, para a previsão da atenuação por chuvas, principal efeito da propagação em freqüências superiores a 10 GHz. Este tr
Publicado em: 2006
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10. Utilização do módulo "creatalink" para a transmissão, em tempo real, de sinais de correção para sistemas GPS diferenciais (DGPS) / Use of creatalink module to transmit in real time corrections signals for differential GPS (DGPS) systems
GPS is a radio navigation system base on a satellite network providing 24 hours radio data to determine point coordinates and world wide coverage. The precision is in the decametric range which is not adequate to many applications. DGPS or Differential GPS is a technique used to improve this precision down to metric level adding informa-tion to the receiver.
Publicado em: 2005
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11. Estudo Analítico e numérico de um enlace digital de comunicação via satélite em condição orbital geo-estacionária / Analytical and numerical analysis of a digital communication geostationary satellite link.
The links of satellites are affected by propagation conditions and distortions that are generated by devices. The propagation losses as well as the passive components attenuation are very simple to analyze, but many calculations involved with the complete link demand to discover the carrier to inter-modulation ratio. This work presents an innovative set of e
Publicado em: 2004
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12. MODELAMENTO DE EFEITOS DE PROPAGAÇÃO EM ENLACES SATÉLITE DE ÓRBITA BAIXA / PROPAGATION EFFECTS IN LOW EARTH ORBIT SATTELITE LINKS
O efeito da atenuação por chuvas em enlaces satélites que operam em frequências acima de 10 GHz é decisivo no cálculo de desempenho do sistema. A evolução da tecnologia dos sistemas satélite e a necessidade de expansão dos serviços de comunicações móveis pessoais levaram ao uso de sistemas de comunicação com satélites de órbita baixa. Estes
Publicado em: 2003