With GPS go miles

Good news for people of free spirit who would like to go where ever they want to go, when ever they want to go with the help of a small television like gadget fitted in their cars known as Global Positioning System [GPS] available for now in countries like America. But bad news for all the paper map books manufacturers as their sales has gone down. A polite, attractive female voice gives turn by turn directions to the place they wish to go in this system.

This system is not brand new. Just that it has reached even the common man in recent days. This technology was initially used by the American army for the purpose of keeping an eye on its enemies activities till some years back. The GPS receiver is the main box that you need for this system. Popular brands like Garmin, TomTom sell it for about $250 with no monthly payments. Only the insurance for cars, which has built-in GPS on its dashboard, is high. Lots of cell phones too have this system.

Just for this purpose there are 24 satellites plus 3 emergency satellites orbiting in space.
All these 27 satellites get their solar power from Sun, which is 12,000 miles away from the earth. If all these 27 satellites die that would be the death of the entire GPS system as well. At present about million Americans use this system.

For example, for the question where am I? If I say – I'm 190 miles from Boston, MA, 52 miles from Trenton, NJ and 81 miles from Philadelphia, PA it’s easy to deduce that I'm in New York, which is exactly what the GPS does. This method is called Trilateration. For the GPS to work it needs to communicate with at least 3 satellites at a particular moment. GPS uses High- Frequency, Low-Power radio signals for this purpose so, you will be in trouble if you are in a place between high-rise buildings or if the weather is bad. Then the polite, sweet voiced lady can't help you.

Otherwise you are free to roam around just about anywhere alone. No need to take a print out of the directions from googlemaps. The sweet lady could even direct you to the wonderful Chettinad Aachi's Non-veg Indian restaurant in New Jersey for this weekend.