Originally developed for military purposes, satellite navigation (sat nav) systems have become valuable tools in assisting travelers find their way in unfamiliar territory. Atlases can be cumbersome and sometimes there is simply no place in which one can pull their vehicle over to study directions. Sat nav systems provide turn by turn instructions via a receiver that attaches to the vehicle's visor, dash, or center console. The peace of mind the system offers is an appealing attribute, so how do sat nav systems work to get people where they wish without getting lost?
The United States manages NAVSTAR and Russia operates GLONASS two representative sat nav systems that function using 20-30 satellites. They are considered medium orbit satellites and rotate around the planet in various orbits. These satellites continually beam signals to Earth, where receivers interpret them. Information such as the time the signal was sent, the precise orbital location of the satellite, and the approximation of the other satellites' locations is included on each signal. The receiver then determines how long it took the signal to reach its receptor and formulates a distance to the satellite. This distance, in conjunction with the satellite's location and the time the signal required to travel the distance, is used to pinpoint the receiver's location.
In order to produce accurate readings, sat nav systems must make instantaneous corrections. Because the signals sent propagate at the speed of light, even slight errors in the calculation of time will throw off the location assessment by a great deal. Just a small discrepancy in the time the signal took to reach the receiver is magnified enormously when multiplied by the large number that is the speed of light. That is why receivers base their calculations and readings on signals from four satellites. Once the position is determined, it appears on the receiver's display so that the user may obtain the data. Users in motion benefit from receivers that utilize animated displays.
Sat nav receivers usually store maps in their database. These maps contain streets, highways, and other landmarks that are coordinated with the signals sent from the satellites. The receiver's position is applied to the internal map and directions are mechanically spoken aloud to the user. The user may also opt to follow an icon that represents his real time position.
Sat nav systems work by combining signals from space with data stored inside a receiver. Those in strange locales are thankful for the help they provide. Travelers have never had such convenience before.
The United States manages NAVSTAR and Russia operates GLONASS two representative sat nav systems that function using 20-30 satellites. They are considered medium orbit satellites and rotate around the planet in various orbits. These satellites continually beam signals to Earth, where receivers interpret them. Information such as the time the signal was sent, the precise orbital location of the satellite, and the approximation of the other satellites' locations is included on each signal. The receiver then determines how long it took the signal to reach its receptor and formulates a distance to the satellite. This distance, in conjunction with the satellite's location and the time the signal required to travel the distance, is used to pinpoint the receiver's location.
In order to produce accurate readings, sat nav systems must make instantaneous corrections. Because the signals sent propagate at the speed of light, even slight errors in the calculation of time will throw off the location assessment by a great deal. Just a small discrepancy in the time the signal took to reach the receiver is magnified enormously when multiplied by the large number that is the speed of light. That is why receivers base their calculations and readings on signals from four satellites. Once the position is determined, it appears on the receiver's display so that the user may obtain the data. Users in motion benefit from receivers that utilize animated displays.
Sat nav receivers usually store maps in their database. These maps contain streets, highways, and other landmarks that are coordinated with the signals sent from the satellites. The receiver's position is applied to the internal map and directions are mechanically spoken aloud to the user. The user may also opt to follow an icon that represents his real time position.
Sat nav systems work by combining signals from space with data stored inside a receiver. Those in strange locales are thankful for the help they provide. Travelers have never had such convenience before.
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