What is GPS?
The Global Positioning System (GPS) is a navigational system that can pinpoint your location on earth. GPS has its origin as a military project that was conceived in 1973 by the US Department of Defence. In the 1980s GPS was made available for commercial use.
Today the GPS system is made up of 24 satellites (with 3 backup satellites) that orbit the planet. The arrangement of the satellites are such, that at any given time 4 satellites are in line of sight with a GPS receiver anywhere in the world.
Even though GPS is a complex technology, its usage is very simple. In order to use GPS all you need is a GPS receiver. The GPS receiver displays its location on the planet in terms of latitude, longitude, height and time. In order to locate its position, the receiver gets signals from at least 4 satellites. In theory using signals from 3 satellites are sufficient, but in practice 4 satellites are used to improve accuracy. The GPS receiver uses a technique called tri-lateration to determine its position in a 3 dimensional space.
GPS receivers have become popular consumer electronic devices in the recent past. Their popularity is so high, nowadays the term GPS is often used to refer to the receiver.
Unlike a subscription service such as mobile phones and xm satellites radios, the GPS infrastructure is provided free of charge. This means that you don’t pay for any connection or service charges. The primary cost involved is the initial equipment cost.
The GPS receiver does not broadcast its location. It only receives signals from the satellites to calculate its position. This means no one can track your movements using GPS technology, unless the GPS receiver has some built in mechanism to relay it’s location to the user. Electronic Pet Tracking System uses GPS receivers with relaying mechanism to track the pet.
Today, a basic GPS receiver device would have an antenna, a 12 channel receiver that can connect up to 12 satellites, a central processing unit, a LCD display and in some cases a base map of a region.
GPS Navigation Systems, Just more than a receiver
A GPS navigation system is more than a receiver. It has an electronic map stored in the memory. Using the location information obtained via the receiver, a GPS navigation system plots the position of the user in an electronic map using mapping software.
The latitude and longitude coordinates reported by the GPS receiver is know as waypoints. A series of connected waypoints make up a route. As the GPS receiver moves the virtual bread crump trail that is left is known as a track.
A typical GPS navigation system provides the user with very useful features as follows:
- The traveling distance between source and destination
- Time since departure
- Current speed
- Average speed for the trip
- A bread crump of trail
- Distance to destinationEstimated time of arrival