For accuracy.
1 satellite can only tell you the distance from that satellite (a 3-d sphere around it).
2 satellites can only tell you what your distance from the two of them are(a 2-d circle between them).
3 satellites can give you 2 single points (1 one the surface of Earth, and one out in the middle of space, and they assume you are on Earth when using GPS).
4 satellites is to give extra accuracy on that point that you are at (4 times as accurate as 3 satellites).
its confusing.
Smartphones use GPS receivers to receive signals from GPS satellites and determine their location. GPS receivers in smartphones work by triangulating the signals from at least four GPS satellites to calculate the phone's latitude, longitude, and altitude.
No, for GPS to work there must be 24 operational satellites in orbit, with 12 of those above the horizon as seen from any point on earth.For a GPS receiver to get a latitude-longitude fix it must receive signals from a minimum of 3 satellites and to also get altitude it must receive signals from a minimum of 4 satellites. Each satellite that it receives above these minimums allows the receiver to get a more precise fix.
GPS signals are processed in the GPS unit and displayed, and they are also processed via three Global Position Satellites. All four units work together and process GPS signals (some to the satellites from the GPS, and some from the satellites to the GPS) to create an accurate position.
Well two of the four are ,the first is a Scientific satellites . The second is a Applications satellites.
GPS positioning refers to the use of signals from satellites to determine the precise location of a person or object on Earth. This technology utilizes a network of satellites orbiting the Earth to triangulate a user's position based on the signals received from at least four satellites. GPS positioning is commonly used in navigation, mapping, and tracking applications.
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.
light emitted by the satellites
four to 10 electrodes are located on the end of the catheters, which have the ability to send electrical signals to stimulate the heart (called pacing) and to receive electrical signals from the heart
Jupiter has four large satellites, but they are not the four largest in the solar system. Jupiter has the largest, 3rd, 4th, and 6th largest satellites. Saturn has the 2nd largest and Earth has the 5th largest satellite. (Naturally I mean "natural satellites", otherwise called moons.)
Jupiter
The four satellites are Jupiter's largest moons. They were found by Galileo Galilei. They are Callisto, Europa, Ganymede and Io.