Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Low Earth orbiting satellite


Related Topics

In the News (Sun 21 Sep 14)

  
  Polar Orbiting Satellites
Different types of satellite orbits have different uses: while the synchronous orbit is best for communication satellites, Lagrangian point orbits help monitor the solar wind before it reaches Earth.
The reason is that the Earth itself orbits the Sun, so that the Sun's position in the sky, relative to the distant stars, slowly rotates around the Earth, one circuit per year.
By placing the satellite in a sun-synchronous orbit near the dawn-dusk plane (90 degrees to the noon-midnight plane described earlier), not only was the interference kept small, but because the orbit's orientation relative to the Sun did not change, the disturbance also stayed more or less the same throughout the mission.
www-istp.gsfc.nasa.gov /Education/wlopolar.html   (917 words)

  
  Encyclopedia: Satellite   (Site not responding. Last check: 2007-11-03)
The general criterion for an object to be a satellite is that the center of mass of the two objects is inside the primary object.
Weather satellites are satellites that primarily are used to monitor the weather and/or climate of the Earth.
A weather satellite is a type of artificial satellite that is primarily used to monitor the weather and/or climate of the Earth.
www.nationmaster.com /encyclopedia/Satellite   (4797 words)

  
 Communications satellite - Open Encyclopedia   (Site not responding. Last check: 2007-11-03)
A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications using radio at microwave frequencies.
Unlike fiber optic communication, satellite communication has a propagation delay (also called a path delay) of at least 270 milliseconds, which is the time it takes the radio signal to travel 35,800 km from earth to a satellite and then back to earth.
A low Earth orbiting satellite is a satellite with a low orbit with an orbital period much shorter than a day.
open-encyclopedia.com /Communications_satellite   (665 words)

  
 Low Earth orbit - Wikipedia, the free encyclopedia
A low Earth orbit (LEO) is an orbit around Earth between the atmosphere and the Van Allen radiation belt, with a low angle of inclination.
Orbits higher than this are subject to early electronic failure because of intense radiation and charge accumulation.
Orbits with a higher inclination angle are usually called polar orbits.
en.wikipedia.org /wiki/Low_Earth_orbiting_satellite   (472 words)

  
 Communications satellite   (Site not responding. Last check: 2007-11-03)
The concept of the communications satellite was first proposed by Arthur C. Clarke, based on 's pseudonymous work from 1929.
Thus Arthur C. Clarke is often quoted as the inventor of the communcations satellite.
It is possible to offer discontinous coverage using a low Earth orbit satellite capable of storing data received while passing over one part of Earth and transmitting it later while passing over another part.
www.serebella.com /encyclopedia/article-Communications_satellite.html   (683 words)

  
 What is satellite? - a definition from Whatis.com - see also: LEO, satellite (transmission)
In general, a satellite is anything that orbits something else, as, for example, the moon orbits the earth.
In a communications context, a satellite is a specialized wireless receiver/transmitter that is launched by a rocket and placed in orbit around the earth.
Thus, the satellite remains over the same spot on the earth's surface at all times, and stays fixed in the sky from any point on the surface from which it can be "seen." So-called weather satellites are usually of this type.
searchmobilecomputing.techtarget.com /sDefinition/0,,sid40_gci212939,00.html   (680 words)

  
 Read about Communications satellite at WorldVillage Encyclopedia. Research Communications satellite and learn about ...   (Site not responding. Last check: 2007-11-03)
satellite dishes used to transmit to or receive from these is called an earth station or teleport.
low Earth orbiting satellite is a satellite with a low orbit that also has an orbital period of much shorter than a day.
Due to the limitations of ground-based amateur equipment, most amateur satellites are launched into fairly low earth orbits, and are designed to deal with only a limited number of brief contacts at any given time.
encyclopedia.worldvillage.com /s/b/Communications_satellite   (779 words)

  
 HST Project Science Office
Special satellites at very high altitudes can remain in contact with a ground station at all times by orbiting the Earth once per day.
It's orbit lies in a region known as the thermosphere, or upper atmosphere.
Since the drag force on a satellite is stronger for lower altitude satellites than for higher ones, the force can be minimized by placing a satellite in an orbit as high as possible.
hstsci.gsfc.nasa.gov /orbit.html   (1391 words)

  
 satellite - a Whatis.com definition - see also: LEO, satellite (transmission)   (Site not responding. Last check: 2007-11-03)
In general, a satellite is anything that orbits something else, as, for example, the moon orbits the earth.
In a communications context, a satellite is a specialized wireless receiver/transmitter that is launched by a rocket and placed in orbit around the earth.
Thus, the satellite remains over the same spot on the earth's surface at all times, and stays fixed in the sky from any point on the surface from which it can be "seen." So-called weather satellites are usually of this type.
searchnetworking.techtarget.com /sDefinition/0,,sid7_gci212939,00.html   (558 words)

  
 UW Madison Satellite Meteorology: Low Earth Orbiting Satellites   (Site not responding. Last check: 2007-11-03)
Satellites in a sunsynchronous orbit circle the earth from pole-to-pole.
Satellites in this orbit view all regions of the earth in a single day and are good for global weather studies.
Sunsynchronous orbits are also referred to as polar orbits as the polar regions are frequently viewed, for example 14 times a day.
itg1.meteor.wisc.edu /wxwise/satmet/lesson1/leo.html   (159 words)

  
 Water Specialties - Flow Measurement Solutions for Water and Wastewater
Conversely, the low-flying LEO satellites have a very small footprint on earth, and must therefore have ground Earth Stations in strategic locations to send and receive signals from the satellites.
These stations receive rebounded signals from satellites in the region and then send them by landline to the Network Control Center in Virginia, where they are routed to a specific client in a particular region of the country.
For example, Gateway Earth Station in St. Johns, Arizona, sends the signal via a dedicated, fiber-optic telecommunication line to the network control center in Virginia, where the data is encapsulated and then routed via frame-relayed format back to SRP in Phoenix by dedicated landline.
www.waterspecialties.com /news_1999_satellite.htm   (1462 words)

  
 Measurement of tropospheric/stratospheric transmission at 10–35 GHz for H2O retrieval in low Earth orbiting ...
Active microwave limb sounding is a possible technique for measuring water vapor in the upper troposphere and lower stratosphere, and here a first assessment of the retrieval capabilities of transmission measurements in the range 10–35 GHz is presented.
The proposed observing system consists of a constellation of low Earth orbiters measuring atmospheric transmission at the frequencies 10.3, 17.2, and 22.6 GHz.
With the assumed instrument characteristics a measurement precision for water vapor in the upper troposphere of 5–10% is obtained, with capability to observe through ice clouds and clouds with a low water content.
www.agu.org /pubs/crossref/2003/2002RS002638.shtml   (354 words)

  
 ICT'98 - Wood et al - Supporting group applications via satellite constellations with multicast
Although originally planned as 21 near-polar orbital planes of 40 active satellites and 4 in-orbit spares per plane at an altitude of 700km, in early 1997 it was scaled back to 12 near-polar planes of 24 active satellites and 3 in-orbit spares at an altitude of 1400km.
For each satellite pair, the satellite furthest from the centre of a GEO footprint that satellite footprints overlap with is used for minimum interference with the GEO satellite.
However, as the satellites move in their orbits it would become necessary to periodically move the core of the tree, and this would also require support for native multicast routing in the satellite on-board switches.
www.cs.ucsb.edu /~almeroth/classes/S99.290I/Satellite.html   (2463 words)

  
 IGS LEO fundamental differences   (Site not responding. Last check: 2007-11-03)
Baslines between LEO satellites or between a LEO receiver and a land-based receiver are limited by the semi-major axis of the LEO orbit.
Orbit determination for the GPS constellation is typically done in the inertial frame.
The region of ionosphere and troposphere that affects the station's observations is constant, and forms the visibility mask for that station (for the GPS satellite constellation).
nng.esoc.esa.de /gps/Fundiff.html   (2151 words)

  
 Low Earth orbit microsatellites for data communications using small terminals
The polar sun-synchronous circular orbit which is a common low Earth orbit choice for remote sensing satellites has a number of advantages for simple communications services.
Although the satellite is mainly visible at low elevation angles the change of range between satellite and ground station gives rise to a change in path loss of some 12dB greater at the horizon than at nadir for an 800km orbit.
Examination of the data available from Geo-stationary systems shows that the low elevation angle effects are not covered by existing geo-stationary propagation models or terrestrial land mobile communications models and in addition that the scintillation effects are dependant upon location and latitude.
www.ee.surrey.ac.uk /SSC/CSER/UOSAT/papers/icdsc10/icdsc10.html   (3294 words)

  
 [No title]
These and other satellite owners are committed to the use of their systems in developing countries and will join in ensuring enough satellite capacity for regular and speedy communications.
The satellites have been used for a range of communications including medical information during the Ebola Crisis in Zaire, administrative communications in Tanzania, child care programmes in Sierra Leone, agricultural research exchange in the Philippines, refugee logistics in Pakistan, power generation station management in Indonesia, and health information in several other countries.
A ground user terminal uses only one satellite at a time, even though there are several satellites in the system; but, a message could be sent by one satellite and a response could be returned by another satellite.
www.itu.int /itudoc/itu-d/wtdc/wtdc98/docs/19rev1_ww7.doc   (2299 words)

  
 Packet Admission Control in a Direct-Sequence Spread-Spectrum LEO Satellite Communications Network   (Site not responding. Last check: 2007-11-03)
To recognize the effect of interferences when their sources are either inside or outside the service area of a satellite, we develop a stochastic model for the location of users.
We will show that the effect of interference on the performance degradation from the users with large propagation distance to their connecting satellites is a dominant factor.
Hence, to improve the performance of the system, we propose a method in which the transmissions of packets are controlled according to their distances to connecting satellites as well as traffic distribution.
www.comsoc.org /sac/private/1997/oct/1649_15sac08-jamalipour.html   (360 words)

  
 ATMOZ-GPS Sounding the Earth's Atmosphere and Ionosphere
FedSat 1 and other satellites to be launched by the CRCSS have to form an integrated system as far as communication, control, and data collection is concerned.
The great amount of atmosphere and image data collected by our LEO satellite during each orbit has to be massaged and compressed on-board so that it can be sent to a ground station during the brief time that the satellite is overhead.
In a larger orbit of 12 hours period are shown the 4 GPS SV's (Space Vehicles) that traverse the same orbit.
www.latrobe.edu.au /crcss/eagle.html   (633 words)

  
 [No title]
He was responsible for the first practical low cost active magnetic and passive gravity gradient control attitude system for a low Earth orbiting satellite.
All specialist hardware on a satellite is expensive, in particular the technology such as sun-sensors, star-sensors, horizon sensors which are conventionally needed in order to determine the pointing direction of a rigid body satellite.
The well known principle is that the GPS satellites in high Earth orbit transmit synchronised pulses (actually in coded form) whose relative time delay as sensed in the LEO enables it to compute its position.
www.ee.surrey.ac.uk /SSC/G3/P6   (1500 words)

  
 [No title]   (Site not responding. Last check: 2007-11-03)
The Bureau's order completes the domestic licensing of the first low-Earth orbiting (LEO) satellite system and heralds the commencement of NVNG-based services on a worldwide basis.
Its system will consist of 36 satellites operating in four inclined and two polar orbital planes, 775 kilometers above the earth.
Four gateway earth station authorizations were issued separately.
www.fcc.gov /ftp/Bureaus/International/Public_Notices/1995/in95-14.txt   (126 words)

  
 A Closeup of Doppler Shift
Satellites travel at much higher speeds, typically 27,000 km/h for a low Earth orbiting satellite.
This is a common orbit for amateur satellites (in fact, the raw data was obtained from pass predictions of UO-14, which is in such an orbit).
Satellite Doppler shift doesn't vary in a simple linear fashion during a pass, but instead has the greatest rate of change at mid pass.
www.qsl.net /vk3jed/doppler.html   (1190 words)

  
 Low earth orbiting facilities
There will be a series of fuel depots in low earth orbit which will provide fuel for lifting payloads to HEO, for lunar missions, for maintaining the proper altitude of the various LEO facilities (called station keeping), and possibly for missions to Mars or to some of the Apollo (earth-crossing orbit) asteroids.
Fuel sent up from earth would be in the form of ice or water which would be electrolyzed in orbit to produce both oxygen and hydrogen.
Low earth orbiting fuel depots could be established with low cost conventional powder guns such as Gerald Bull's supergun.
www.androidpubs.com /Chap05.htm   (5887 words)

  
 LEO Satellites Blast Into New Year - 1/5/1998 - Wireless Week - CA4550   (Site not responding. Last check: 2007-11-03)
Little LEO Orbcomm launched eight satellites Dec. 23 from the NASA flight facility at Wallops Island, Va. The satellites flew onboard a Pegasus XL rocket provided by parent company Orbital Sciences Corp. The launch represents the first commercial little LEO deployment, with the exception of Orbcomm's previous launch via an experimental license.
One of the advantages of the Pegasus is that it is deployed from a carrier aircraft rather than from the ground, Parker said.
The launch brings Iridium's in-orbit constellation to 46 satellites, with 20 remaining for deployment later this year.
www.wirelessweek.com /article/CA4550.html?spacedesc=&stt=001   (418 words)

  
 Satellite Phone Rentals, Satellite Phones and Satellite Phone Service - Iridium Phone Rentals at Cellular Express Phone ...
Globalstar Satellite Phones utilizes Qualcomm's CDMA (Code Division Multiple Access) technology which ensures that calls are exceptionally secure and clear, with high cellular-like voice quality.
This system is the only provider of truly global satellite voice and data solutions with complete global coverage (including oceans, airways and Polar regions).
Through a constellation of 66 Low-Earth Orbiting satellites, Iridium delivers essential communication services to and from remote areas where terrestrial communications are not available.
www.cellularexpressphonerentals.com /satellite.html   (179 words)

  
 U.S. Legal Personal Locator Beacons (PLBs)   (Site not responding. Last check: 2007-11-03)
Both ground station and beacon must be in view of the low-earth orbiting satellite, within this footprint.
Average initial detection/alerting by orbiting satellites is about 45 minutes, maximum 90 minutes.
Satellites process only encoded data, other signals are rejected.
www.bonus.com /contour/Survival_training/http@@/www.equipped.org/406_vs_1215.htm   (554 words)

  
 Stevens Water Monitoring Systems
Stevens GR 3320 Satellite DSP (Digital Signal Processing) is the new Demodulator designed to perform the signal processing function required in receiving messages from GOES (Geostationary Operational Environmental Satellite) satellite transmissions at the new 300 or 1200 bps (bits per second).
ORBCOMM is a low earth orbiting (LEO) satellite data communication system that is two-way and provides worldwide coverage.
The ORBCOMM Satellite Transceiver (two-way) is easy to install at a relative low cost and minimal maintenance requirements.
www.stevenswater.com /telemetry_com/satellite.aspx   (557 words)

  
 U.S. Air Force Plans Geosynchronous Surveillance System   (Site not responding. Last check: 2007-11-03)
WASHINGTON — In the midst of its delayed procurement of a low Earth-orbiting satellite for monitoring space objects, the U.S. Air Force is planning a spacecraft that would carry out the same function from a much higher geosynchronous orbit, according to service officials.
The MSX satellite is expected to reach the end of its useful lifetime in 2006, however, a fact that the Air Force had cited as the rationale for its earlier plan to launch the first SBSS satellite that same year.
The Pentagon can develop an understanding of most of the satellites that are launched around the world through other measures, and would only be in trouble if it was at war with a country that suddenly launched new spacecraft, he said.
www.space.com /spacenews/archive04/systemarch_031504.html   (625 words)

  
 IRC Network - Technology profiles diffused via the Automatic Matching Tool   (Site not responding. Last check: 2007-11-03)
Inventors in Latvia have developed the Satellite Laser Ranging telescope with its optical and mechanical components, electronics, computer software and GPS-steered timing system with the aim to design a mobile SLR of small size with a high capability to track fast-moving Low Earth Orbiting (LEO) satellites including the zenith zone.
Inventors in Latvia have developed the Satellite Laser Ranging (SLR) telescope with its optical and mechanical components, electronics, computer software and GPS (global positioning system)-steered timing system with the aim to design a mobile SLR of small size with a high capability to track fast-moving Low Earth Orbiting (LEO) satellites including the zenith zone.
The main innovation of the pilot project is the semi-automated lightweight SLR for observation of low Earth orbiting satellites.
www.ircnet.lu /matching/completerec.cfm?BBS_ID=10979&COMPANY=21172   (742 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.