GPS is quite common nowadays. It can be found in cars , taxis and in handheld. Recently, on a kayaking trip into the Ubin Mangrove ( see previous posting), one of us brought a handheld GPS; it showed the route we travelled into the mangrove! no need to be afraid of getting lost - cool.
Depending on devices, the accuracy can go up to 10m. Although for military use, with super duper computers, accuracy up to mm is possible. Imagine locating a mm spot anywhere on Earth!!!
Beside civilian uses, it is also used in military, for example to cruise missiles and precision-guided munitions.
For more applications of GPS:
http://en.wikipedia.org/wiki/GPS_applications
Do you know?- GPS is owned by the United States and is allowed for public use ( in 1996 during Bill Clinton's presidency) .
- It works by 24 satellites orbitting round the earth.
- You need to communicate to at least 4 satellites to 'log on' your position.
- To compute such precise timing in such a big distance, GPS needs Einstein's General Theory of Relativity.( to account for the gravitational redshift)
- And US can choose to shut the system down ... and there goes our taxi booking ...
- A few other countries are trying come out with their own Global Navigation Satellites System. They are
- Beidou by China
- Galileo by EU
- Glonass by Russis
- Indian Regionaly Navigational Satellite System by India (regional)
