What is GPS :

• GPS stands for Global Positioning System. A GPS device is either an independent portable device or is inbuilt in a mobile phone, digicam or a car to help you navigate in an unknown city or locality.
• A GPS device uses satellites to pinpoint its exact location on the Earth within an area of about 50 sq. ft.
• Many high-end mobile phones like Nokia N95 8GB, Asus P750, Sony Ericsson P1, etc. come with inbuilt GPS receiver. Similiarly, top versions of some expensive cars and even some digital-cameras have pre-installed GPS devices.
• GPS was developed by United States’ Defence Department solely for military purposes. But after realizing its numerous civilian applications, it made it available for everyone in larger societal interest.
• Other countries are also developing its alternatives e.g. COMPASS by China, Galileo by European Union, GLONASS by Russia. So future proof GPS devices need to be compatible with more than one system for greater accuracies!

Why GPS is a buzz-word these days :

• GPS technology has recently arrived in India with detailed city maps.
• GPS devices can guide you to a destination unknown to you with precise Voice Prompts like “Turn left then Right” or “Your Banks’ ATM 500m ahead” or “Fuel Station 8 km straight”.
• You don’t need to meet with blank looks with passers-by, when asking for directions and forget the risk of some stranger misguiding you.
• Geo-tagging of photographs: Now photographs taken by a GPS integrated digicam will also show you the location & GPS co-ordinates, where they were clicked along with the date and time.
• New sports such as Geo-caching are played with the help of GPS devices (to locate a hidden cache), just like Treasure Hunt is (or rather wasJ) played with the help of a map.

Indian Cities with GPS Maps :

• At present GPS maps are available only for 8 major Indian cities of India. Maps for metro cities like Delhi, Mumbai, Chennai & Kolkata are quite detailed …atleast around the city-centre
• Detailed maps are available for Bangalore, Hyderabad, Ahmedabad & Pune too.
• Two major GPS solution provider in India are SatNav Technologies and MapMyIndia. Both these are promising to release maps of many more Indian cities, this year. Maps of smaller cities like Jaipur, Lucknow & Indore are expected to be out in a few months.
• Maps for all state capitals with major roads & Points of Interests (PoIs) are already available.
• These will get more & more detailed with time as map-makers regularly keep updating the maps incorporating new changes & developments to make them more precise, contemporary and useful.

How it works :

• Basic principle behind this technology is the measurement of distance of a GPS receiver from various satellites, whose whereabouts are known to us. With the help of this data, whereabouts of the GPS receiver (or the person carrying it) can be concluded.
• More than 2 dozen GPS satellites keep orbiting our planet transmitting digital signals to GPS receiver on the ground.
• GPS receivers only receive these signals, they do not transmit any. i.e. it’s a one way communication from GPS satellites to the receivers.
• The GPS receivers calculate the time taken to receive a signal. Multiplying it with the velocity of light gives its distance from that particular satellite.
• All GPS satellites synchronize operations and signals are transmitted at the same instant indicating their location & current time. GPS operations depend on very accurate time reference. Hence these satellites use atomic clocks installed on them for this purpose.
• When measurements from 3-4 or more satellites to same point (i.e. the GPS receiver) are known, the location of this point (GPS receiver) can be easily ascertained in terms of latitude, longitude, altitude [Imagine intersection of 3 imaginary spheres of different radii and centres at a single point].
• Now detailed maps of cities are prepared in form of latitude, longitude & altitude with their corresponding landmarks or commonly known names of these places. Thus the position of the GPS receiver is interpreted on these maps and it is easily understood by a common man.

The Last Word :

GPS is a very great technology to assist you in reaching a place without getting lost. But its not foolproof. GPS technology provides quite a good accuracy, but it is directly dependent on the maps where it is interpreted by a common man. And at times maps ditch us as even the best of them are a bit erratic at some places! Sometimes it may tell you to drive into a wall or into a river! But too techno-savvy ones have a blind faith on the tech-word. On May 11, 2007, a driver followed satnav instructions in the dark and her car was hit by a train on a rail crossing that was not shown on the system [Reference]. There are incidents of people who trusted their GPS devices to an extent of actually driving into a lake. So mind it, GPS some times denotes ji, piye-se (Yeah, drunk-like)!

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