Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Introduction to Global Positioning System01:30

Introduction to Global Positioning System

The Global Positioning System (GPS) revolutionized positioning on Earth, providing precise location data through satellite ranging. The GPS system was developed in 1978 by the U.S. Department of Defense  for military use, and it became available for civilian applications in 1983, transforming fields including navigation, fleet management, and time synchronization for telecommunications systems.GPS consists of satellites in medium Earth orbit, about 20,200 kilometers above the surface,...
Types of Global Positioning System Surveys01:30

Types of Global Positioning System Surveys

GPS surveying methods vary in application, accuracy, and data collection techniques, catering to diverse surveying and mapping needs. Static GPS, kinematic GPS, and real-time kinematic (RTK) surveying are widely used. Each technique offers distinct advantages.Static GPS involves placing one receiver at a known reference point and another at the target point. It collects exact positional data by observing multiple satellite ranges over an extended period, achieving centimeter-level accuracy for...
Circular Orbits and Critical Velocity for Satellites01:16

Circular Orbits and Critical Velocity for Satellites

The Moon orbits around the Earth. In turn, the Earth (and other planets) orbit the Sun. The space directly above our atmosphere is filled with artificial satellites in orbit. One can examine the circular orbit, the simplest kind of orbit, to understand the relationship between the speed and the period of planets and satellites with respect to their positions and the bodies that they orbit.
Nicolaus Copernicus (1473-1543) first suggested that the Earth and all other planets orbit the Sun in...
Errors in Global Positioning System01:26

Errors in Global Positioning System

Global Positioning System (GPS) technology has revolutionized navigation and positioning, but its accuracy is often compromised by various errors. These errors, stemming from environmental, satellite, and receiver-related factors, require careful mitigation to ensure reliable performance across applications.Atmospheric ErrorsGPS signals travel through the Earth’s ionosphere and troposphere, introducing delays which affect accuracy. The ionosphere is strongly influenced by charged particles,...
Energy of a Satellite in a Circular Orbit01:11

Energy of a Satellite in a Circular Orbit

Thousands of artificial satellites orbit the Earth every day at various distances from the Earth. Satellites that orbit the Earth below an altitude of 1,600 km are considered to be orbiting in low-Earth orbit (LEO). Research satellites and Earth observation satellites are usually placed in LEO, and mostly orbit the Earth in elliptical orbits. Navigation satellites are placed in medium-Earth orbit (MEO), ranging from 2,000 km to 36,000 km from the surface of the Earth. Meanwhile, communication...
The Antenna Complex01:15

The Antenna Complex

Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

[Statistical principles of "good clinical practice" in veterinary medicine--a position paper for planning, implementation and evaluation of empirical studies].

DTW. Deutsche tierarztliche Wochenschrift·2002
Same author

Psychotic symptoms and emotional distress in patients with Guillain-Barré syndrome.

European neurology·2002
Same author

Determinants of gonorrhoea infection among STD clinic attenders in Trinidad--I: sociodemographic factors, knowledge, risk perception and history of STD.

International journal of STD & AIDS·2002
Same author

Determinants of gonorrhoea infection among STD clinic attenders in Trinidad--II: sexual behavioural factors.

International journal of STD & AIDS·2002
Same author

Antibiotic resistant N. gonorrhoeae in Trinidad and Tobago.

Cellular and molecular biology (Noisy-le-Grand, France)·2002
Same author

[Sampling plans in microbiological criteria for food and their "performance criteria"].

Berliner und Munchener tierarztliche Wochenschrift·2002

相关实验视频

Updated: Jul 12, 2026

Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements
09:36

Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements

Published on: June 25, 2021

通信卫星:为INTELSAT VI进行倒计时

L Pollack, H Weiss

    Science (New York, N.Y.)
    |February 10, 1984
    PubMed
    概括

    卫星技术彻底改变了全球通信,增加了400倍的国际电话电路,并将通话成本降低了12,000%. 未来的卫星有望实现更大的容量和效率.

    科学领域:

    • 卫星通信 卫星通信
    • 电信工程 电信工程 电信工程
    • 太空技术 太空技术

    背景情况:

    • 通信卫星 (COMSAT) 自成立以来,促进了全球连接的巨大扩张.
    • 国际电话电路的数量增长了400倍,在过去二十年中,电话费用下降了12,000%.
    • 目前的全球通信依赖于14颗卫星在地球同步轨道上,连接109个国家.

    研究的目的:

    • 突出卫星通信技术的进步.
    • 预测卫星电信的未来趋势和容量需求.
    • 详细介绍卫星技术的发展及其对全球通信的影响.

    主要方法:

    • 分析国际电话电路的增长和降低成本.
    • 审查卫星组件和能力的技术改进.
    • 检查卫星轨道力学和网络配置.

    主要成果:

    • 卫星传输带宽已经从50增加到3000多兆赫.
    • 由于技术改进,卫星的运行寿命已从1.5年延长到10年.
    • 第六代INTELSAT卫星将提供4万多个频道和每台2个电视节目.

    结论:

    更多相关视频

    A Video Surveillance System to Monitor Breeding Colonies of Common Terns (Sterna Hirundo)
    07:39

    A Video Surveillance System to Monitor Breeding Colonies of Common Terns (Sterna Hirundo)

    Published on: July 22, 2018

    Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite
    07:00

    Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite

    Published on: March 11, 2020

    相关实验视频

    Last Updated: Jul 12, 2026

    Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements
    09:36

    Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements

    Published on: June 25, 2021

    A Video Surveillance System to Monitor Breeding Colonies of Common Terns (Sterna Hirundo)
    07:39

    A Video Surveillance System to Monitor Breeding Colonies of Common Terns (Sterna Hirundo)

    Published on: July 22, 2018

    Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite
    07:00

    Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite

    Published on: March 11, 2020

    • 卫星技术的持续进步对于满足不断增长的全球交通需求至关重要.
    • 未来的卫星代将包含更高的频率 (20/30 GHz),机载处理和高级调制以增加容量.
    • 预计在未来几十年中,卫星通信将变得更加有效和有能力.