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Why is it necessary to have 3 satellites signals to determine elevation when using a gps receiver?
Wiki User
∙ 6y ago
The receiver calculates the distance to each satellite from which it can receive a signal. The positions of the satellites are known, so with three known points (the satellite locations) there are two geometrically possible positions that are the correct distance from each one. With a fourth satellite and known point, there is only one position that is the correct distance from all of them.
Three points will always define a flat surface or plane between them, and for every location that is a given distance from each of the reference points, there will be another location on the other side of the plane that is the same distance away from each reference point - if you imagine the plane as a mirror, then the reflection of the first location is the second position. With a fourth reference point - as long as it is not on the same plane - there is no 'mirror' and thus no mirror position. As the GPS satellites are orbiting in ellipses around the Earth, it's impossible for four to be in the same plane, so this never arises...
Adriana Doyle
Wiki User
∙ 15y agoTriangulation.
Imagine that you can know your distance from any point, and you are good at math.
If you know your distance from one point. You can be anywhere on a circle.
If you know your distance from two points, you can be on the two points where a circle intersects.
If you know your distance from three points. There is only one place you can be.
Wiki User
∙ 12y agoThe receiver calculates the distance to each satellite from which it can receive a signal. The positions of the satellites are known, so with three known points (the satellite locations) there are two geometrically possible positions that are the correct distance from each one. With a fourth satellite and known point, there is only one position that is the correct distance from all of them.
Three points will always define a flat surface or plane between them, and for every location that is a given distance from each of the reference points, there will be another location on the other side of the plane that is the same distance away from each reference point - if you imagine the plane as a mirror, then the reflection of the first location is the second position. With a fourth reference point - as long as it is not on the same plane - there is no 'mirror' and thus no mirror position. As the GPS satellites are orbiting in ellipses around the Earth, it's impossible for four to be in the same plane, so this never arises...
Wiki User
∙ 13y agoonly 3 converges to 2 totally different solutions: one on earth surface and one thousands of miles up in space.
If we are sure we can ignore the one in space safely, then 3 is just enough.
Ginger
Because normally we need refer high accurate data. Al least three satellites we can get some accurate data but recommended four satellites signal for get high accurate data for our need.
Moreover these satellites are may should situated as a triangulation, because data is in everyway and we need to catch them our device , so catch to these data we need to distribute satellites data for get suitable information for our need. Otherwise we can't get accurate and suitable data from one satellite or not situated as a triangulation satellites .
Wiki User
∙ 13y agoThree gives you x,y position in 2 dimensions. The 4th gives you altitude allowing your receiver to tell you how much above sea level you are.
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How do global positioning systems use elevation point on earth system to find latitude and longitude?
GPS receivers do not 'use' elevation for anything. They use the signals from several satellites simultaneously to calculate the latitude, longitude, and elevation of the receiver's location. It takes a minimum of three satellites to calculate the latitude and longitude, a minimum of four satellites to calculate the latitude, longitude, and elevation, if more satellites can be found the latitude, longitude, and elevation calculations can be refined more accurately.
How do global positioning systems use elevation points earths system to find latitude and longitude?
GPS receivers do not 'use' elevation for anything. They use the signals from several satellites simultaneously to calculate the latitude, longitude, and elevation of the receiver's location. It takes a minimum of three satellites to calculate the latitude and longitude, a minimum of four satellites to calculate the latitude, longitude, and elevation, if more satellites can be found the latitude, longitude, and elevation calculations can be refined more accurately.
How many satellites does it take for GPS to find something?
Your receiver must pick up at least 4 to get an accurate 3D lock. If your receiver can safely assume you are on or near surface of earth it can get a good 2D lock with just 3. This is usually a safe assumption to make, especially with civilian receivers. Less than 3, all it can do is set its clock.
What information can a gps unit give you?
-- latitude of the receiver -- longitude of the receiver -- elevation of the receiver -- the time
How do global positioning systems use elevation points on earths system to find latitude and longatude?
It's all down to timing ! Ground stations 'decode' the amount of time it takes for a signal to 'bounce' from the satellite to the Earth. This pinpoints the location of each GPS satellite - and thus the necessary calculations produce the coordinates
How many gps satellites are required to pinpoint your location on earth surface?
To determine latitude and longitude the minimum number of satellites that the receiver must lock onto is three. To also determine elevation the minimum number of satellites that the receiver must lock onto is four. If the receiver can lock onto more satellites then it can improve the calculations to get a more precise location.
How do global positioning systems use elevation on earths system to find latitude and longitude?
GPS receivers do not 'use' elevation for anything. They use the signals from several satellites simultaneously to calculate the latitude, longitude, and elevation of the receiver's location. It takes a minimum of three satellites to calculate the latitude and longitude, a minimum of four satellites to calculate the latitude, longitude, and elevation, if more satellites can be found the latitude, longitude, and elevation calculations can be refined more accurately.
How do global positioning systems use elevation points earths system to find latitude and longitude?
GPS receivers do not 'use' elevation for anything. They use the signals from several satellites simultaneously to calculate the latitude, longitude, and elevation of the receiver's location. It takes a minimum of three satellites to calculate the latitude and longitude, a minimum of four satellites to calculate the latitude, longitude, and elevation, if more satellites can be found the latitude, longitude, and elevation calculations can be refined more accurately.
How do global positioning systems use elevation point on earth system to find latitude and longitude?
GPS receivers do not 'use' elevation for anything. They use the signals from several satellites simultaneously to calculate the latitude, longitude, and elevation of the receiver's location. It takes a minimum of three satellites to calculate the latitude and longitude, a minimum of four satellites to calculate the latitude, longitude, and elevation, if more satellites can be found the latitude, longitude, and elevation calculations can be refined more accurately.
How many satellites does it take for GPS to find something?
Your receiver must pick up at least 4 to get an accurate 3D lock. If your receiver can safely assume you are on or near surface of earth it can get a good 2D lock with just 3. This is usually a safe assumption to make, especially with civilian receivers. Less than 3, all it can do is set its clock.
What information can a gps unit give you?
-- latitude of the receiver -- longitude of the receiver -- elevation of the receiver -- the time
What is meant by Global Positioning Satellite?
A Global Positioning satellite is one of several satellites that orbit the earth constantly broadcasting a signal the give their location. Collectively these satellites are called the Globle Positioning System or GPS. Global Positioning means the system is used to determine your position on the globe -- your latitude and longitude. GPS receivers can receive signals from these satellites and use them to calculate where on the earth the receiver (and thus the person with the receiver) is. Visit the links below for more information on GPS satellites.
If your GPS system is stolen out of your tractor can it be relocated when it is turned back on?
Unfortunately, a GPS is a receiver only. It locates its position on the surface of the earth by determining its distance from a series of satellites. It does not transmit any information back to the satellites, which would be necessary for a satellite to locate the GPS.
How do global positioning systems use elevation points on earths system to find latitude and longatude?
It's all down to timing ! Ground stations 'decode' the amount of time it takes for a signal to 'bounce' from the satellite to the Earth. This pinpoints the location of each GPS satellite - and thus the necessary calculations produce the coordinates
Is GPS and GPRS same or different?
No they are not the same.General Packet Radio Service (GPRS) is for voice communications. Global Position System (GPS) is the use of satellites to determine latitude and longitude which is transmitted to a receiver on earth. It gives you direct location of the receiver, most of the time within feet.
How does a GPS receiver work?
A GPS (short for "Global Positioning System") is an electronic device that measures its distance to three or more satellites to determine its precise location. There are 24 such satellites in fixed orbits around the world. All of the satellites are perfectly synchronized, and send out digital radio transmissions broadcasting the current time. Your GPS receiver receives three or more of these signals, where the distance to the satellite will delay the signal just a tiny bit. The GPS receiver uses the relative delays to determine its precise location. GPS receivers are available from Garmin, Magellan, Tom Tom, and a number of other companies. Many newer cellphones also have a built-in GPS receiver.
WHAT IS THE what is the Use of satellites in tv transmission?
it is used to transmit information from the provider to a requesting receiver.
