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Topic: Satellite navigation

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  Dive and Discover : Oceanographic Tools: Satellite Navigation
Each satellite is in a constant, or fixed, orbit around the Earth and its position is determined very precisely by the military using several ground stations and antennas around the world.
Satellites send radio waves to the ship and the clocks measure how long it takes for the signals to travel from the satellites to the ship.
The satellites are spaced in orbit so that at any time a minimum of 6 satellites will be in view to users anywhere in the world.
www.divediscover.whoi.edu /tools/navigation-satellite.html   (548 words)

  Satellite navigation system - Wikipedia, the free encyclopedia
The satellite uses an atomic clock to maintain synchronization of all the satellites in the constellation.
Satellite navigation receivers reduce errors by using combinations of signals from multiple satellites and multiple correlators, and then using techniques such as Kalman filtering to combine the noisy, partial, and constantly changing data into a single estimate for position, time, and velocity.
Satellite navigation also allows forces to be directed and to locate themselves more easily, reducing the fog of war.
en.wikipedia.org /wiki/Satellite_navigation_system   (1393 words)

 Satellite navigation system Info - Encyclopedia WikiWhat.com   (Site not responding. Last check: )
Due to the relatively clear line of site between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few metres in real time.
The satellite broadcasts a signal that contains the position of the satellite and the precise time the signal was transmitted (using an atomic clock), encoded into a short burst of information in the microwave region.
The innaccuracy of the civilian signal was deliberately encoded so as not to change very quickly, for instance the entire eastern US area might read 30m off, but 30m off everywhere and in the same direction.
www.wikiwhat.com /encyclopedia/s/sa/satellite_navigation_system.html   (1226 words)

 Read about Satellite navigation system at WorldVillage Encyclopedia. Research Satellite navigation system and learn ...   (Site not responding. Last check: )
satellites to enable mobile receivers on the ground to determine their exact location.
Doppler effect: the satellites traveled on well-known paths and broadcast on a well known frequency.
essential service, countries without their own satellite navigation systems effectively become client states of those which supply these services.
encyclopedia.worldvillage.com /s/b/Satellite_navigation   (1314 words)

 car satellite navigation & satellite navigation uk
The Car Navigation System promises to be a valuable aid for travelers, sales people, delivery personnel, real estate agents, drivers of emergency vehicles....anyone and everyone who needs to reach a variety of destinations as quickly and efficiently as possible.
We specialise in supplying discount satellite navigation and discount garmin satellite navigationservices to individuals and businesses as well as all establishments.
A GPS receiver must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement.
www.mynewcommunications.co.uk   (1663 words)

 [2.0] International Navigation Satellite Systems   (Site not responding. Last check: )
A contract for the testbed satellite was issued to Surrey Satellite Technology LTD in the UK in July 2003, with the 400 kilogram spacecraft to be launched no later than the second half of 2005, as required by International Telecommunications Union (ITU) rules relevant to the Galileo project.
A network of satellites were to be flown with secondary payloads that would monitor the rescue band and determine its location with enough accuracy to allow SAR teams to fly into the area and home in on the beacon signal.
The satellites travel in a known orbit, and the slight shifts in frequency of a (more or less) stationary beacon due to the motion of the satellite can be used to provide the general location of the beacon, allowing SAR teams to get close enough to pick up the beacon.
www.vectorsite.net /ttgps2.html   (3482 words)

 GPS Satellite navigation   (Site not responding. Last check: )
The Navigation Message is a 50 Hz signal consisting of data bits that describe the GPS satellite orbits, clock corrections, and other system parameters.
The GPS Navigation Message consists of time-tagged data bits marking the time of transmission of each subframe at the time they are transmitted by the SV.
Multiple SVs and a navigation solution (or a known position for a timing receiver) permit SV Time to be set to an accuracy limited by the position error and the pseudo-range error for each SV.
home.earthlink.net /~fjolles/gps.htm   (2250 words)

 Galileo - European Satellite Navigation System
The clearest of these is the fact that satellite navigation will become a fully redundant service for civil aviation users in the event of a satellite or system failure.
Despite the fact that satellite navigation has been with us for some time and that airlines have made significant investments, there has been, so far, relatively little return in terms of improved navigation services to airlines.
The Galileo Navigation System Control Centre will collect the raw data from the ground stations that are monitoring the orbits of individual satellites and calculate the ephemeris data and timing offset for each satellite.
www.aatl.net /publications/galileo.htm   (2285 words)

 Garmin: What is GPS?   (Site not responding. Last check: )
The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.
A GPS receiver must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement.
Ideal satellite geometry exists when the satellites are located at wide angles relative to each other.
www.garmin.com /aboutGPS   (1082 words)

 Energy and Transport - GALILEO
Today, satellite navigation is continuing this tradition, while offering, thanks to leading-edge technology, an accuracy far beyond that possible by simply observing the sun and the stars.
The operating principle is simple: the satellites in the constellation are fitted with an atomic clock measuring time very accurately.
By reading the incoming signal, it can thus recognise the particular satellite, determine the time taken by the signal to arrive and calculate the distance from the satellite.
ec.europa.eu /dgs/energy_transport/galileo/index_en.htm   (402 words)

 Orbit Determination and Satellite Navigation
It was not until the late 1950s, however, with the launches of the Sputnik and Vanguard satellites, that the modern discipline of orbit determination was born.
Navigation around the world has been dramatically changed by the Global Positioning System (GPS), and the power of this system is derived first and foremost from the orbit-determination process that drives it.
GPS satellite signals are directed toward Earth in a broadcast pattern that is slightly wider than the planet.
www.aero.org /publications/crosslink/summer2002/04.html   (3467 words)

 Bluetooth GPS receivers & PluggedIn: Have Palm, will travel -- Military Bluetooth GPS receivers not get lost   (Site not responding. Last check: )
Satellite navigation -- once a $3,000 luxury for yachtsmen, big-rig truckers and back-country campers -- has dropped in price and grown in portability, having found its way into Palm and Pocket PC handheld computers.
Navigation was first commercially embraced in sailing and yachting, where the price of a positioning system was dwarfed by the price of the boat.
Satellite information pinpoints the user's position on the slope or in relation to the shore, and projects it on a detailed map.
www.biz-portal.com /gps/bluetoothgpsb.html   (849 words)

 AllRefer.com - navigation satellite (Space Exploration) - Encyclopedia
navigation satellite, artificial satellite designed expressly to aid the navigation of sea and air traffic.
Early navigation satellites, from the Transit series launched in 1960 to the U.S. navy's Navigation Satellite System, relied on the Doppler shift.
Based on the shift in the satellite's frequency, a ship at sea could accurately determine its longitude and latitude.
reference.allrefer.com /encyclopedia/N/navigsat.html   (290 words)

 Satellite Navigation Using GPS
The launch of the first Sputnik triggered the initial challenge in satellite navigation: the determination of the characteristics of the orbit of the satellite, using the variations in the signal that was being radiated by the satellite.
When four satellites are being tracked, GPS allows for real-time autonomous determination of the position of the satellite, with an accuracy equivalent to that obtained with non-precise ground tracking methods.
The navigation data and observations of these precisely located ground stations can be processed in order to check their integrity and to estimate the error in the signal for each GPS satellite.
esapub.esrin.esa.it /bulletin/bullet90/b90mur.htm   (3937 words)

 EUROPA - Energy and Transport - GALILEO
Today, satellite navigation is continuing this tradition, while offering, thanks to leading-edge technology, an accuracy far beyond that possible by simply observing the sun and the stars.
The operating principle is simple: the satellites in the constellation are fitted with an atomic clock measuring time very accurately.
The satellites emit personalised signals indicating the precise time the signal leaves the satellite.
europa.eu.int /comm/dgs/energy_transport/galileo/index_en.htm   (400 words)

 HERON & HEART used in satellite navigation system
GPS signals, which are received from a constellation of satellites orbiting in space, are weak by the time they reach the earth and they can easily be disrupted by electrical interference.
RSL is now involved in researching the next generation of GPS/Galileo satellite navigation receivers for use in high integrity civil navigation applications.
There the FPGA is used to extract the different satellite channels, and to pass their status on to the C6000.
www.hunteng.co.uk /customer/raytheon.htm   (391 words)

 Satellite Navigation   (Site not responding. Last check: )
satellite navigation is not just for those with top of the range bmws and mercedes’.
in fact, satellite navigation is increasingly used by haulage companies, field sales forces, engineers and bus companies to ensure prompt arrivals and control wages.
if your drivers spend more than about 2% of their time lost or in endless diversions then satellite navigation could save you money.
www.cactustelecoms.sageweb.co.uk /satellitenavigation.htm   (152 words)

 BBC NEWS | England | Lincolnshire | Satellite navigation tracks seals
Satellite technology is being used to successfully track seals in the Wash off the Lincolnshire/Norfolk coast.
The Satellite data logging tags had been painlessly glued to the fur on the necks of the seals, named Nemo, Hercules, Shrek, Morocco, Snoopy and Skippy by rescue workers.
They sent regular updates to satellites showing where each seal was and whether it was diving, swimming at the surface or resting on the beach.
news.bbc.co.uk /go/newsFeedXML/moreover/-/1/hi/england/lincolnshire/4412231.stm   (182 words)

 Satellite Navigation Test Solutions
Our specialist team has been involved in every aspect of satellite and navigation test from the earliest days of GPS simulation to current work on Galileo simulation and new applications.
Over the past 5 years we have developed new systems for testing modernized GPS signals, all Galileo signals and services, augmentation systems, Assisted-GPS in mobile devices, in vehicle navigation systems, aircraft landing systems, adaptive antennas, inertial navigation systems and classified military navigation signals.
Whatever your application, whatever the conditions and however challenging your test need, we aim to have a test solution to support your navigation and positioning test needs.
www.spirentcom.com /analysis/index.cfm?media=4&ws=312   (184 words)

 Satellite Navigation Forensics
Most modern vehicles use Satellite Navigation systems, and it is the information in these systems that can give assistance in providing information to others, (be they law enforcement officers, defence lawyers, employers or members of the public).
If an accused person states that he was in one place, but his car Satellite Navigation system states that at the time that the vehicle was 200 miles away, the information given adds to the intelligence that the law enforcement agency has against the accused, or is even enough to charge the said accused person.
There may be a history of drug abuse, of unsafe relationships, and using the Satellite Navigation system in their car, they would be able to get a true idea of whether or not the person in question has indeed been where they said they had.
www.satnavforensics.com   (602 words)

 History of Satellite Navigation
Since the positions of the satellites are known, either through previous publication or as part of the satellite's broadcast information, the user's position can be calculated.
The DECCA system was a low-frequency hyperbolic navigation system covering much of western Europe, parts of Canada, the Persian Gulf and the Bay of Bengal.
The user was able to calculate position to within a few hundred meters as long as the user knew his altitude and the satellite ephemeris.
ares.redsword.com /gps/old/sum_pre.htm   (1020 words)

 Thales Navigation :: Products and Solutions :: About Satellite Navigation   (Site not responding. Last check: )
Global satellite navigation is an exciting technology, providing enhanced productivity and accuracy in a vast number of industries.
A Global Navigation Satellite System (GNSS) is a network of satellites that transmits high-frequency radio signals containing time and distance data that can be picked up by a receiver, allowing the user to pinpoint their precise location anywhere around the globe.
A third GNSS named GALILEO, after the Italian astronomer of the early 1600s, is currently being developed in Europe to specifically provide a higher standard of integrity and reliability, required to ensure the safety of lives during transport by air, land and sea without the use of additional augmentation systems.
www.thalesnavigation.com /en/products/aboutgps   (326 words)

 SPACE.com -- Satellite Navigation: GPS Grows Up, Market Booms   (Site not responding. Last check: )
Space is the new frontier for useful and playful high-tech consumer gadgetry, as satellite technology developed for the military comes into its own running a burgeoning variety of portable devices that let people know where the heck they are.
The time difference tells the GPS receiver how far away the satellite is. With distance measurements from multiple satellites, the receiver can determine the user's position.
A receiver must be locked on to the signal of at least three satellites to calculate a two-dimensional position -- latitude and longitude -- and track movement.
www.space.com /businesstechnology/technology/satcom_gps_overview_031105.html   (1386 words)

 ESA - Navigation
11 October 2007 In the frame of the European Global Navigation Satellite System Evolution Programme, ESA is launching a call for ideas for advanced radio navigation applications concepts.
26 September 2007 A key meeting to enhance the scientific use of Galileo and contribute to the science-based development of Global Navigation Satellite Systems is being held at the 'Cité de l'Espace' in Toulouse on 1 to 4 October.
This is the first colloquium on scientific and fundamental aspects of the Galileo programme.
www.esa.int /export/esaSA/navigation.html   (152 words)

 Car satellite navigation - satellite navigation UK   (Site not responding. Last check: )
Car satellite navigation manufacturers typically charge £2,000 or more for a built-in satellite navigation system, while a dedicated GPS (Global Positioning System) unit with an integrated map display can cost as little as £200.
Our cheap in car satellite navigation make the ideal gift for students, military and all walks of life.
The perfect cheap car satellite navigation all come installed with all the software you'll need for your home and office.
www.mncgroup.co.uk /car-satellite-navigation.htm   (1488 words)

 New Scientist Breaking News - US and Europe to combine satellite navigation
The EU is keen to have a global navigation satellite system that is independent of GPS, which is run by the US military.
Richard Langley, a satellite communications expert at the University of New Brunswick in Canada, agrees: “It’s basically a win-win for both sides.
For example, GPS currently fails to pinpoint devices in built-up areas, but with twice as many satellites, its use in cars and for other location-based applications, would be far more common, he says.
www.newscientist.com /article.ns?id=dn6068   (587 words)

 DDJ>Satellite Navigation & the Internet   (Site not responding. Last check: )
Satellite navigation (SN) addresses the seemingly simple — but in reality very complex — question of "Where am I?" This question is answered with the help of GPS satellites that broadcast pseudorandom digital signals to users.
This is done by measuring the delay between the signal generated by the receiver and that received from a given satellite.
By calculating the distance to three satellites, the receiver software calculates the user's 3D position with respect to a given coordinate system, normally called "navigation solution." This is reasonable, since there are three unknown variables.
www.ddj.com /documents/s=4069/ddj0203a/0203a.htm   (714 words)

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