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	<title>Comments for FTA VIP</title>
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	<description>FTA Files, FTA Instructions and FTA Keys to get your FTA Receiver up and running.</description>
	<pubDate>Fri, 20 Nov 2009 23:13:10 +0000</pubDate>
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		<title>Comment on FTA VIP BLOG by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=15&#038;cpage=1#comment-11</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 21:50:13 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=15#comment-11</guid>
		<description>FTA FILES &amp; FTA SUPPORT 
FTA support includes full instructions for updating your FTA receiver, Fta files, Fta keys, Fta software and tech support.
We have step by step, easy to follow instructions to get your FTA receiver up and running. In the case you run into a problem with your FTA receiver we include tech support to get you back up in no time. FTA VIP is a leader in FTA software and Nagra2 support.
We support all major brand FTA receivers. If you have questions or need help programming your FTA receiver our VIP Members 
Club is your answer. You should know how to program your own fta receiver and with the information in our Private VIP Club you will learn just that.</description>
		<content:encoded><![CDATA[<p>FTA FILES &#038; FTA SUPPORT<br />
FTA support includes full instructions for updating your FTA receiver, Fta files, Fta keys, Fta software and tech support.<br />
We have step by step, easy to follow instructions to get your FTA receiver up and running. In the case you run into a problem with your FTA receiver we include tech support to get you back up in no time. FTA VIP is a leader in FTA software and Nagra2 support.<br />
We support all major brand FTA receivers. If you have questions or need help programming your FTA receiver our VIP Members<br />
Club is your answer. You should know how to program your own fta receiver and with the information in our Private VIP Club you will learn just that.</p>
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		<title>Comment on FTA VIP BLOG by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=15&#038;cpage=1#comment-10</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 21:49:45 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=15#comment-10</guid>
		<description>MISSION STATEMENT 
"Give a man a fish; you have fed him for today.
Teach a man to fish; and you have fed him for a lifetime." -Author Unknown


We here at FTA VIP believe that we can provide our customers with the knowledge and
tools that they need to program their receivers from the comfort of their own home. 

FTA VIP can help you fix your receiver without having to drive across town and hand 
your receiver to a third party whom you have never met and may not trust. 
Our VIP section can provide you with support that in the end will save you both time and money.

Our support will provide our customers with information about the products that they 
are using to receive FTA signals so that they can make informed decisions and figure 
out troubleshooting solutions on their own.

We do not sell our customers files or keys, we provide our customers with knowledge 
and support to get their receivers up and running.</description>
		<content:encoded><![CDATA[<p>MISSION STATEMENT<br />
&#8220;Give a man a fish; you have fed him for today.<br />
Teach a man to fish; and you have fed him for a lifetime.&#8221; -Author Unknown</p>
<p>We here at FTA VIP believe that we can provide our customers with the knowledge and<br />
tools that they need to program their receivers from the comfort of their own home. </p>
<p>FTA VIP can help you fix your receiver without having to drive across town and hand<br />
your receiver to a third party whom you have never met and may not trust.<br />
Our VIP section can provide you with support that in the end will save you both time and money.</p>
<p>Our support will provide our customers with information about the products that they<br />
are using to receive FTA signals so that they can make informed decisions and figure<br />
out troubleshooting solutions on their own.</p>
<p>We do not sell our customers files or keys, we provide our customers with knowledge<br />
and support to get their receivers up and running.</p>
]]></content:encoded>
	</item>
	<item>
		<title>Comment on FTA VIP BLOG by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=15&#038;cpage=1#comment-9</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 21:49:29 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=15#comment-9</guid>
		<description>Fta Files ,Fta Support and Fta Receivers 

FTA VIP is your FTA head quarters for Fta hardware and Fta support. 

We ship our hardware Worldwide and have quickly formed a loyal customer base 
and a strong following. 
We continue that today by gathering all of our own Fta information along with information 
from other Fta sources to bring you everything you need in one place. 

There's no need to search forums endlessly for what you need.

We have everything you need here in a safe and reliable place.

Free-to-Air (FTA) is exactly what the name implies.
The channels are free to view and there are no monthly charges. 
All the systems that we offer are DVB (Digital Video Broadcast) compliant.
We can also help you save money by doing your own installation. 
We offer step by step guides, support and photos to help get you started. 

If you have any questions about FTA VIP and it's operations, please contact us.</description>
		<content:encoded><![CDATA[<p>Fta Files ,Fta Support and Fta Receivers </p>
<p>FTA VIP is your FTA head quarters for Fta hardware and Fta support. </p>
<p>We ship our hardware Worldwide and have quickly formed a loyal customer base<br />
and a strong following.<br />
We continue that today by gathering all of our own Fta information along with information<br />
from other Fta sources to bring you everything you need in one place. </p>
<p>There&#8217;s no need to search forums endlessly for what you need.</p>
<p>We have everything you need here in a safe and reliable place.</p>
<p>Free-to-Air (FTA) is exactly what the name implies.<br />
The channels are free to view and there are no monthly charges.<br />
All the systems that we offer are DVB (Digital Video Broadcast) compliant.<br />
We can also help you save money by doing your own installation.<br />
We offer step by step guides, support and photos to help get you started. </p>
<p>If you have any questions about FTA VIP and it&#8217;s operations, please contact us.</p>
]]></content:encoded>
	</item>
	<item>
		<title>Comment on FTA VIP BLOG by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=15&#038;cpage=1#comment-8</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 21:49:01 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=15#comment-8</guid>
		<description>Fta Files and Fta File Support for all major Free To Air Receivers.  Including Viewsat, Sonicview, Pansat, Coolsat and many more Fta Receivers by Fta Files Professionals. Fta Vip Is your FTA head quarters for Fta Hardware, Fta Files and Fta File Support.  

We have everything you need here in a safe and reliable place. FTA file support includes full instructions, Fta files and Fta keys for updating your FTA receiver. We have step by step, easy to follow instructions to get your FTA receiver up and running with best Fta Files. All Fta Files are tested and approved by fta files professionals.</description>
		<content:encoded><![CDATA[<p>Fta Files and Fta File Support for all major Free To Air Receivers.  Including Viewsat, Sonicview, Pansat, Coolsat and many more Fta Receivers by Fta Files Professionals. Fta Vip Is your FTA head quarters for Fta Hardware, Fta Files and Fta File Support.  </p>
<p>We have everything you need here in a safe and reliable place. FTA file support includes full instructions, Fta files and Fta keys for updating your FTA receiver. We have step by step, easy to follow instructions to get your FTA receiver up and running with best Fta Files. All Fta Files are tested and approved by fta files professionals.</p>
]]></content:encoded>
	</item>
	<item>
		<title>Comment on GPS receiver by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=35&#038;cpage=1#comment-7</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 20:40:23 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=35#comment-7</guid>
		<description>Differential GPS
So far, we've learned how a GPS receiver calculates its position on earth based on the information it receives from four located satellites. This system works pretty well, but inaccuracies do pop up. For one thing, this method assumes the radio signals will make their way through the atmosphere at a consistent speed (the speed of light). In fact, the Earth's atmosphere slows the electromagnetic energy down somewhat, particularly as it goes through the ionosphere and troposphere. The delay varies depending on where you are on Earth, which means it's difficult to accurately factor this into the distance calculations. Problems can also occur when radio signals bounce off large objects, such as skyscrapers, giving a receiver the impression that a satellite is farther away than it actually is. On top of all that, satellites sometimes just send out bad almanac data, misreporting their own position. 
Differential GPS (DGPS) helps correct these errors. The basic idea is to gauge GPS inaccuracy at a stationary receiver station with a known location. Since the DGPS hardware at the station already knows its own position, it can easily calculate its receiver's inaccuracy. The station then broadcasts a radio signal to all DGPS-equipped receivers in the area, providing signal correction information for that area. In general, access to this correction information makes DGPS receivers much more accurate than ordinary receivers. 

The most essential function of a GPS receiver is to pick up the transmissions of at least four satellites and combine the information in those transmissions with information in an electronic almanac, all in order to figure out the receiver's position on Earth. 

Once the receiver makes this calculation, it can tell you the latitude, longitude and altitude (or some similar measurement) of its current position. To make the navigation more user-friendly, most receivers plug this raw data into map files stored in memory. 



Photo courtesy Garmin
The StreetPilot II, a GPS receiver with built-in maps for drivers
 


You can use maps stored in the receiver's memory, connect the receiver to a computer that can hold more detailed maps in its memory, or simply buy a detailed map of your area and find your way using the receiver's latitude and longitude readouts. Some receivers let you download detailed maps into memory or supply detailed maps with plug-in map cartridges. 

A standard GPS receiver will not only place you on a map at any particular location, but will also trace your path across a map as you move. If you leave your receiver on, it can stay in constant communication with GPS satellites to see how your location is changing. With this information and its built-in clock, the receiver can give you several pieces of valuable information: 

How far you've traveled (odometer) 
How long you've been traveling 
Your current speed (speedometer) 
Your average speed 
A "bread crumb" trail showing you exactly where you have traveled on the map 
The estimated time of arrival at your destination if you maintain your current speed 
For lots more information on GPS receivers and related topics, check out the links on the next page.</description>
		<content:encoded><![CDATA[<p>Differential GPS<br />
So far, we&#8217;ve learned how a GPS receiver calculates its position on earth based on the information it receives from four located satellites. This system works pretty well, but inaccuracies do pop up. For one thing, this method assumes the radio signals will make their way through the atmosphere at a consistent speed (the speed of light). In fact, the Earth&#8217;s atmosphere slows the electromagnetic energy down somewhat, particularly as it goes through the ionosphere and troposphere. The delay varies depending on where you are on Earth, which means it&#8217;s difficult to accurately factor this into the distance calculations. Problems can also occur when radio signals bounce off large objects, such as skyscrapers, giving a receiver the impression that a satellite is farther away than it actually is. On top of all that, satellites sometimes just send out bad almanac data, misreporting their own position.<br />
Differential GPS (DGPS) helps correct these errors. The basic idea is to gauge GPS inaccuracy at a stationary receiver station with a known location. Since the DGPS hardware at the station already knows its own position, it can easily calculate its receiver&#8217;s inaccuracy. The station then broadcasts a radio signal to all DGPS-equipped receivers in the area, providing signal correction information for that area. In general, access to this correction information makes DGPS receivers much more accurate than ordinary receivers. </p>
<p>The most essential function of a GPS receiver is to pick up the transmissions of at least four satellites and combine the information in those transmissions with information in an electronic almanac, all in order to figure out the receiver&#8217;s position on Earth. </p>
<p>Once the receiver makes this calculation, it can tell you the latitude, longitude and altitude (or some similar measurement) of its current position. To make the navigation more user-friendly, most receivers plug this raw data into map files stored in memory. </p>
<p>Photo courtesy Garmin<br />
The StreetPilot II, a GPS receiver with built-in maps for drivers</p>
<p>You can use maps stored in the receiver&#8217;s memory, connect the receiver to a computer that can hold more detailed maps in its memory, or simply buy a detailed map of your area and find your way using the receiver&#8217;s latitude and longitude readouts. Some receivers let you download detailed maps into memory or supply detailed maps with plug-in map cartridges. </p>
<p>A standard GPS receiver will not only place you on a map at any particular location, but will also trace your path across a map as you move. If you leave your receiver on, it can stay in constant communication with GPS satellites to see how your location is changing. With this information and its built-in clock, the receiver can give you several pieces of valuable information: </p>
<p>How far you&#8217;ve traveled (odometer)<br />
How long you&#8217;ve been traveling<br />
Your current speed (speedometer)<br />
Your average speed<br />
A &#8220;bread crumb&#8221; trail showing you exactly where you have traveled on the map<br />
The estimated time of arrival at your destination if you maintain your current speed<br />
For lots more information on GPS receivers and related topics, check out the links on the next page.</p>
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	</item>
	<item>
		<title>Comment on GPS receiver by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=35&#038;cpage=1#comment-6</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 20:39:20 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=35#comment-6</guid>
		<description>GPS Calculations
On the previous page, we saw that a GPS receiver calculates the distance to GPS satellites by timing a signal's journey from satellite to receiver. As it turns out, this is a fairly elaborate process. 
At a particular time (let's say midnight), the satellite begins transmitting a long, digital pattern called a pseudo-random code. The receiver begins running the same digital pattern also exactly at midnight. When the satellite's signal reaches the receiver, its transmission of the pattern will lag a bit behind the receiver's playing of the pattern. 


Photo courtesy U.S. Army
A GPS satellite
 


The length of the delay is equal to the signal's travel time. The receiver multiplies this time by the speed of light to determine how far the signal traveled. Assuming the signal traveled in a straight line, this is the distance from receiver to satellite. 

In order to make this measurement, the receiver and satellite both need clocks that can be synchronized down to the nanosecond. To make a satellite positioning system using only synchronized clocks, you would need to have atomic clocks not only on all the satellites, but also in the receiver itself. But atomic clocks cost somewhere between $50,000 and $100,000, which makes them a just a bit too expensive for everyday consumer use. 

The Global Positioning System has a clever, effective solution to this problem. Every satellite contains an expensive atomic clock, but the receiver itself uses an ordinary quartz clock, which it constantly resets. In a nutshell, the receiver looks at incoming signals from four or more satellites and gauges its own inaccuracy. In other words, there is only one value for the "current time" that the receiver can use. The correct time value will cause all of the signals that the receiver is receiving to align at a single point in space. That time value is the time value held by the atomic clocks in all of the satellites. So the receiver sets its clock to that time value, and it then has the same time value that all the atomic clocks in all of the satellites have. The GPS receiver gets atomic clock accuracy "for free." 

When you measure the distance to four located satellites, you can draw four spheres that all intersect at one point. Three spheres will intersect even if your numbers are way off, but four spheres will not intersect at one point if you've measured incorrectly. Since the receiver makes all its distance measurements using its own built-in clock, the distances will all be proportionally incorrect. 

The receiver can easily calculate the necessary adjustment that will cause the four spheres to intersect at one point. Based on this, it resets its clock to be in sync with the satellite's atomic clock. The receiver does this constantly whenever it's on, which means it is nearly as accurate as the expensive atomic clocks in the satellites. 

In order for the distance information to be of any use, the receiver also has to know where the satellites actually are. This isn't particularly difficult because the satellites travel in very high and predictable orbits. The GPS receiver simply stores an almanac that tells it where every satellite should be at any given time. Things like the pull of the moon and the sun do change the satellites' orbits very slightly, but the Department of Defense constantly monitors their exact positions and transmits any adjustments to all GPS receivers as part of the satellites' signals. 


In the next section, we'll look at errors that may occur and see how the GPS receiver corrects them.</description>
		<content:encoded><![CDATA[<p>GPS Calculations<br />
On the previous page, we saw that a GPS receiver calculates the distance to GPS satellites by timing a signal&#8217;s journey from satellite to receiver. As it turns out, this is a fairly elaborate process.<br />
At a particular time (let&#8217;s say midnight), the satellite begins transmitting a long, digital pattern called a pseudo-random code. The receiver begins running the same digital pattern also exactly at midnight. When the satellite&#8217;s signal reaches the receiver, its transmission of the pattern will lag a bit behind the receiver&#8217;s playing of the pattern. </p>
<p>Photo courtesy U.S. Army<br />
A GPS satellite</p>
<p>The length of the delay is equal to the signal&#8217;s travel time. The receiver multiplies this time by the speed of light to determine how far the signal traveled. Assuming the signal traveled in a straight line, this is the distance from receiver to satellite. </p>
<p>In order to make this measurement, the receiver and satellite both need clocks that can be synchronized down to the nanosecond. To make a satellite positioning system using only synchronized clocks, you would need to have atomic clocks not only on all the satellites, but also in the receiver itself. But atomic clocks cost somewhere between $50,000 and $100,000, which makes them a just a bit too expensive for everyday consumer use. </p>
<p>The Global Positioning System has a clever, effective solution to this problem. Every satellite contains an expensive atomic clock, but the receiver itself uses an ordinary quartz clock, which it constantly resets. In a nutshell, the receiver looks at incoming signals from four or more satellites and gauges its own inaccuracy. In other words, there is only one value for the &#8220;current time&#8221; that the receiver can use. The correct time value will cause all of the signals that the receiver is receiving to align at a single point in space. That time value is the time value held by the atomic clocks in all of the satellites. So the receiver sets its clock to that time value, and it then has the same time value that all the atomic clocks in all of the satellites have. The GPS receiver gets atomic clock accuracy &#8220;for free.&#8221; </p>
<p>When you measure the distance to four located satellites, you can draw four spheres that all intersect at one point. Three spheres will intersect even if your numbers are way off, but four spheres will not intersect at one point if you&#8217;ve measured incorrectly. Since the receiver makes all its distance measurements using its own built-in clock, the distances will all be proportionally incorrect. </p>
<p>The receiver can easily calculate the necessary adjustment that will cause the four spheres to intersect at one point. Based on this, it resets its clock to be in sync with the satellite&#8217;s atomic clock. The receiver does this constantly whenever it&#8217;s on, which means it is nearly as accurate as the expensive atomic clocks in the satellites. </p>
<p>In order for the distance information to be of any use, the receiver also has to know where the satellites actually are. This isn&#8217;t particularly difficult because the satellites travel in very high and predictable orbits. The GPS receiver simply stores an almanac that tells it where every satellite should be at any given time. Things like the pull of the moon and the sun do change the satellites&#8217; orbits very slightly, but the Department of Defense constantly monitors their exact positions and transmits any adjustments to all GPS receivers as part of the satellites&#8217; signals. </p>
<p>In the next section, we&#8217;ll look at errors that may occur and see how the GPS receiver corrects them.</p>
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	<item>
		<title>Comment on GPS receiver by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=35&#038;cpage=1#comment-5</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 20:38:52 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=35#comment-5</guid>
		<description>3-D Trilateration
Fundamentally, three-dimensional trilateration isn't much different from two-dimensional trilateration, but it's a little trickier to visualize. Imagine the radii from the previous examples going off in all directions. So instead of a series of circles, you get a series of spheres. 
If you know you are 10 miles from satellite A in the sky, you could be anywhere on the surface of a huge, imaginary sphere with a 10-mile radius. If you also know you are 15 miles from satellite B, you can overlap the first sphere with another, larger sphere. The spheres intersect in a perfect circle. If you know the distance to a third satellite, you get a third sphere, which intersects with this circle at two points. 

The Earth itself can act as a fourth sphere -- only one of the two possible points will actually be on the surface of the planet, so you can eliminate the one in space. Receivers generally look to four or more satellites, however, to improve accuracy and provide precise altitude information. 



In order to make this simple calculation, then, the GPS receiver has to know two things: 

The location of at least three satellites above you 
The distance between you and each of those satellites 
The GPS receiver figures both of these things out by analyzing high-frequency, low-power radio signals from the GPS satellites. Better units have multiple receivers, so they can pick up signals from several satellites simultaneously. 

Radio waves are electromagnetic energy, which means they travel at the speed of light (about 186,000 miles per second, 300,000 km per second in a vacuum). The receiver can figure out how far the signal has traveled by timing how long it took the signal to arrive. In the next section, we'll see how the receiver and satellite work together to make this measurement.</description>
		<content:encoded><![CDATA[<p>3-D Trilateration<br />
Fundamentally, three-dimensional trilateration isn&#8217;t much different from two-dimensional trilateration, but it&#8217;s a little trickier to visualize. Imagine the radii from the previous examples going off in all directions. So instead of a series of circles, you get a series of spheres.<br />
If you know you are 10 miles from satellite A in the sky, you could be anywhere on the surface of a huge, imaginary sphere with a 10-mile radius. If you also know you are 15 miles from satellite B, you can overlap the first sphere with another, larger sphere. The spheres intersect in a perfect circle. If you know the distance to a third satellite, you get a third sphere, which intersects with this circle at two points. </p>
<p>The Earth itself can act as a fourth sphere &#8212; only one of the two possible points will actually be on the surface of the planet, so you can eliminate the one in space. Receivers generally look to four or more satellites, however, to improve accuracy and provide precise altitude information. </p>
<p>In order to make this simple calculation, then, the GPS receiver has to know two things: </p>
<p>The location of at least three satellites above you<br />
The distance between you and each of those satellites<br />
The GPS receiver figures both of these things out by analyzing high-frequency, low-power radio signals from the GPS satellites. Better units have multiple receivers, so they can pick up signals from several satellites simultaneously. </p>
<p>Radio waves are electromagnetic energy, which means they travel at the speed of light (about 186,000 miles per second, 300,000 km per second in a vacuum). The receiver can figure out how far the signal has traveled by timing how long it took the signal to arrive. In the next section, we&#8217;ll see how the receiver and satellite work together to make this measurement.</p>
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		<title>Comment on GPS receiver by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=35&#038;cpage=1#comment-4</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 20:38:18 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=35#comment-4</guid>
		<description>2-D Trilateration
Imagine you are somewhere in the United States and you are TOTALLY lost -- for whatever reason, you have absolutely no clue where you are. You find a friendly local and ask, "Where am I?" He says, "You are 625 miles from Boise, Idaho." 
This is a nice, hard fact, but it is not particularly useful by itself. You could be anywhere on a circle around Boise that has a radius of 625 miles, like this: 


 


You ask somebody else where you are, and she says, "You are 690 miles from Minneapolis, Minnesota." Now you're getting somewhere. If you combine this information with the Boise information, you have two circles that intersect. You now know that you must be at one of these two intersection points, if you are 625 miles from Boise and 690 miles from Minneapolis. 


 


If a third person tells you that you are 615 miles from Tucson, Arizona, you can eliminate one of the possibilities, because the third circle will only intersect with one of these points. You now know exactly where you are -- Denver, Colorado. 


 


This same concept works in three-dimensional space, as well, but you're dealing with spheres instead of circles. In the next section, we'll look at this type of trilateration.</description>
		<content:encoded><![CDATA[<p>2-D Trilateration<br />
Imagine you are somewhere in the United States and you are TOTALLY lost &#8212; for whatever reason, you have absolutely no clue where you are. You find a friendly local and ask, &#8220;Where am I?&#8221; He says, &#8220;You are 625 miles from Boise, Idaho.&#8221;<br />
This is a nice, hard fact, but it is not particularly useful by itself. You could be anywhere on a circle around Boise that has a radius of 625 miles, like this: </p>
<p>You ask somebody else where you are, and she says, &#8220;You are 690 miles from Minneapolis, Minnesota.&#8221; Now you&#8217;re getting somewhere. If you combine this information with the Boise information, you have two circles that intersect. You now know that you must be at one of these two intersection points, if you are 625 miles from Boise and 690 miles from Minneapolis. </p>
<p>If a third person tells you that you are 615 miles from Tucson, Arizona, you can eliminate one of the possibilities, because the third circle will only intersect with one of these points. You now know exactly where you are &#8212; Denver, Colorado. </p>
<p>This same concept works in three-dimensional space, as well, but you&#8217;re dealing with spheres instead of circles. In the next section, we&#8217;ll look at this type of trilateration.</p>
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		<title>Comment on GPS receiver by admin</title>
		<link>http://ftavip.com/FtaBlog/?p=35&#038;cpage=1#comment-3</link>
		<dc:creator>admin</dc:creator>
		<pubDate>Sat, 02 Feb 2008 20:32:02 +0000</pubDate>
		<guid isPermaLink="false">http://ftavip.com/FtaBlog/?p=35#comment-3</guid>
		<description>In this article, we'll find out how these handy guides pull off this amazing trick. As we'll see, the Global Positioning System is vast, expensive and involves a lot of technical ingenuity, but the fundamental concepts at work are quite simple and intuitive. 


When people talk about "a GPS," they usually mean a GPS receiver. The Global Positioning System (GPS) is actually a constellation of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails). The U.S. military developed and implemented this satellite network as a military navigation system, but soon opened it up to everybody else. 


Photo courtesy NASA
NAVSTAR GPS satellite
 


Each of these 3,000- to 4,000-pound solar-powered satellites circles the globe at about 12,000 miles (19,300 km), making two complete rotations every day. The orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites "visible" in the sky. 



Photo courtesy U.S. Department of Defense
Artist's concept of the GPS satellite constellation
 


A GPS receiver's job is to locate four or more of these satellites, figure out the distance to each, and use this information to deduce its own location. This operation is based on a simple mathematical principle called trilateration. Trilateration in three-dimensional space can be a little tricky, so we'll start with an explanation of simple two-dimensional trilateration.</description>
		<content:encoded><![CDATA[<p>In this article, we&#8217;ll find out how these handy guides pull off this amazing trick. As we&#8217;ll see, the Global Positioning System is vast, expensive and involves a lot of technical ingenuity, but the fundamental concepts at work are quite simple and intuitive. </p>
<p>When people talk about &#8220;a GPS,&#8221; they usually mean a GPS receiver. The Global Positioning System (GPS) is actually a constellation of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails). The U.S. military developed and implemented this satellite network as a military navigation system, but soon opened it up to everybody else. </p>
<p>Photo courtesy NASA<br />
NAVSTAR GPS satellite</p>
<p>Each of these 3,000- to 4,000-pound solar-powered satellites circles the globe at about 12,000 miles (19,300 km), making two complete rotations every day. The orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites &#8220;visible&#8221; in the sky. </p>
<p>Photo courtesy U.S. Department of Defense<br />
Artist&#8217;s concept of the GPS satellite constellation</p>
<p>A GPS receiver&#8217;s job is to locate four or more of these satellites, figure out the distance to each, and use this information to deduce its own location. This operation is based on a simple mathematical principle called trilateration. Trilateration in three-dimensional space can be a little tricky, so we&#8217;ll start with an explanation of simple two-dimensional trilateration.</p>
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