Global Positioning System ( GPS ) was initially created by American Department of Defence (DOD). It was actually designed to run with the support of 24 satellites, in which 3 satellites have been replaced by the new ones. But now about 30 satellites are orbiting around our earth and the approximate distance between the earth and those satellites is 20200 kilo meters. Here is a brief history about the navigation system and the early models used.
Compass and sextant
Mankind were tried to find a way to know where they were. They needed a system or device to guide them to reach a particular destination and wanted to return safely. Coastlines were helpful for the seamen to follow the routes. Compass and sextant were the previous system used for navigational purposes.
The compass needle will point north therefore they knew the direction to which they were travelling. The sextant was used to find out the exact angles of stars, the moon and the sun with the help of adjustable mirror.
After a long interval, radio based navigation system were used at the end of 20 th Century. War ships and airplanes were used land based radio navigation system. The limitation of this radio based navigation system is the inability to cover a wide area with accuracy. American Navy decided to do an experiment with the satellite navigation system.
Why are the satellites used?
These satellites perform as an agent to transmit signals to the earth. GPS receiver has to be installed with the GPS system to receive the signals from those satellites. Still the GPS Sat Nav system is being utilised for multiple fields like aviation, orientation ashore and nautical navigation.
Most of this system is now used for land surveying and also to find out the land navigation especially when you travel to a new place or destination. With this system, you can find out the exact location of a place by receiving signals from the satellites. The perfect name of this system is NAVSTAR. It is broadly known as Navigation System for Timing and Ranging. But in colloquial terms we say as Global positioning System (GPS).
To utilise this system, you are supposed to do one thing. That is you have to buy a perfect GPS receiver to receive the GPS signals from the satellite. It is possible to utilise this system anywhere in the UK . The minimum requirement of this GPS system is not to be in the way of satellites. A lot of new companies have come up with different models of satellite navigation systems. The most prominent among them are TomTom, Navman, Garmin, Sony, etc.