Guide Manual

NextGen GPS

By far the most happening field these days is Navigation. For ages we have been hearing about how easy it will be to find routes to your destination and as a popular TV commercial states Never get lost again. Finally its starting to become a reality, largely because GPS is now easily available to masses.
Availability of stand-alone GPS navigation devices and built-in GPS inside smartphones are two common reasons for the growing popularity of navigation tchnologies. Not to forget the fact that maps are now easily available and in many choices as almost every vendor is looking to encash upon in the opportunity with its own maps. With maps its not just that you can easily find routes or plan your travel effectively through desktop maps. Many other interesting applications of map have come up.

In this story we will first tell you all you must know about GPS. Then we will take a look at how war of maps online as well on mobile platform is shaping up and tell you about the latest navigation solutions.

What is GPS?
GPS is short for Global Positioning System. It is a technology for anyone who wants to know where they are, where they have been or to find out how to get somewhere. To start using it, all you need is a GPS receiver. There are no charges apart from the initial cost of hardware. If you decide to go for navigation with detailed maps, then there is usually a one-time charge for that as well.

The Basic Premise
Imagine the earth to be covered with horizontal and vertical lines; the horizontal ones called latitudes (or parallels, since they are all parallel to each other) and the vertical ones called longitudes (or meridians; they converge at the north and south poles). These lines are further divided into minutes and seconds. Knowing the latitude and longitude of a place, you can get there using GPS.

There is a network of 24 NAVSTAR (Navigation Satellite Timing and Ranging) satellites orbiting the earth, powered by the sun, and put in place by the U.S.Dept of Defense. Theyve been in orbit since 1978, pre-dating even the personal computer! Their orbits are so arranged so that at any given point in time and at any place on the surface of the earth, at least four satellites will be visible to a GPS device. A GPS device can then pinpoint its location on the earths surface (its latitude and longitude) by measuring its distance from these satellites. The process by which it does this is called triangulation.

How it works
For a GPS device to calculate a location (its latitude and longitude), it needs to know where the satellites are and how far away they are. Supposing it gets a fix on one satellite first and it calculates the distance to the satellite as 12,000 kms. By that logic, it could be anywhere on the surface of an imaginary sphere with a radius of 12,000 kms and with the satellite at the center. Once four satellites get locked on, all these imaginary spheres will intersect at only one common point: the current location. There are variations too: A-GPS, or Assisted GPS uses GSM cell locations to augment tracking; WAAS or Wide Area Augmentation System uses satellites and ground stations that provide GPS signal corrections, increasing accuracy. There can be an unlimited number of simultaneous GPS users. This is because a GPS device only receives signals transmitted from the satellites to coordinate a location. They do not communicate with the satellites.

Limitations
GPS works everywhere on earth, except inside buildings, basements, in caves and underwater. GPS reception is also affected by weather and cloud conditions. Interruptions in signal may also occur when youre driving through a tunnel or standing stationary between very tall buildings.


Microsoft Virtual Earth offers 3D Birds Eye view of selected locations, to give users almost there feeling while exploring maps
Accuracy
Recreational GPS devices are built to offer good performance at a low price. Hence accuracy is not the prime concern. These consumer use devices (and the navigation devices that you see today) which have an accuracy of about 20–40 meters. GPS units used by surveyors usually have an accuracy of one meter. More accurate GPS systems used by the worlds militaries can have accuracy down to one centimeter. This is accomplished by using GPS in conjunction with accurate altimeters and differential GPS (with the GPS unit interacting with base stations in addition to satellites). Some other uses: its not just location though, GPS can be used for a variety of purposes. UK based RaceLogic uses it in their VBox equipment for accurate vehicle performance measurement (speed, acceleration, and deceleration). This equipment is used by automobile testers, manufacturers and racing teams worldwide.

GPS can also be used for location tracking of moving vehicles; which can in turn be used for recovery of stolen cars, to help a customer accurately track courier deliveries, to help a taxi company keep track of its cabs or to help a shipping company monitor its shipments. Recovery of stolen vehicles is the newest trend to catch on in India. With a small, hidden GPS receiver in your car, you will accurately be able to pinpoint its exact location if stolen, and recover it with ease.
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