Global Positioning System (GPS)
Throughout history, Man has been going places, crossing oceans and exploring new continents. Over time, he has developed many navigational techniques. However, even though many of these techniques proved useful and contributed greatly to Mankind’s achievements, they are also fallible- each with their own limitations.
Some disadvantages of other navigation systems:
1. Landmarks : It only works in a localised area and is subjected any movement of the observer. Destruction of the environment also affects your position.
2. Deduced/dead reckoning : It relatively complicated and requires systematic charting. Its accuracy largely depends on the measurement tools, which are normally rather primitive. Errors can accumulate and cause large deviation from the actual position.
3. Celestial Navigation : This method depends heavily on the weather condition. For example, overcast or fog may hinder sightings of the celestial bodies. And may also affect shadow observations (eg. Viking sun-shadow board)
Hence to combat these, the U.S. Department of Defense pumped in $12 billion into inventing an extremely precise form of global positioning, which also do not have the problems plaguing current navigational techniques.
Introducing the Global Positioning System (GPS), a resource that exceeded its original design goals. Nowadays, everyone from scientists, sailors to taxi dispatchers are using this system to be more efficient and productive.
The Global Positioning System (GPS) is a worldwide radio-navigation system formed from by 24 satellites orbiting the earth and their 5 ground stations. These satellites are used as reference points to calculate positions on earth up to accuracy of a few metres. GPS is the first positioning system of its sort to offer highly precise location data for any point on the planet, in any weather.
GPS works by a principle called ‘triangulation”. To do that, it uses the travel time of radio signals from three satellites to measure the distance of the satellites from the point on earth. The intersection of these three spheres will give the location of the point.
Below is a very good website-cum-game from NOVA Online. It explains in a very fun and interesting way, the mechanisms behind GPS.
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