What is GPS? How Does it Work?

The Global Positioning System (GPS) is made up of satellites, ground stations, and receivers.

GPS is a system of 30+ navigation satellites circling Earth. We know where they are because they constantly send out signals. A GPS receiver in your phone listens for these signals. Once the receiver calculates its distance from four or more GPS satellites, it can figure out where you are.

Satellites act like the stars in constellations—we know where they are supposed to be at any given time.

The ground stations use radar to make sure they are actually where we think they are.

A receiver, like you might find in your phone or in your parent's car, is constantly listening for a signal from these satellites. The receiver figures out how far away they are from some of them.

Once the receiver calculates its distance from four or more satellites, it knows exactly where you are. 

Global Positioning System: Working Principle

• The basic principle is the transmission of radio signals with satellites. Let’s see what exactly it means. To determine your location using GPS, your device needs to determine its exact distance from 4 GPS satellites, and their exact location when they send a scheduled signal.
• GPS satellites are a line of sight instruments. Hence, wherever you are on the planet, at least four GPS satellites are ‘visible’ at any time. Each one constantly transmits information about its exact position and the current time at regular intervals.
• The receiver in your device can identify individual satellites, knows the schedule for sending these signals, and can determine how far away each satellite is based on how long it took for the messages to arrive. Since the signals travel at the speed of light, that time delay can be converted to distance.
• Once it has information on how far away at least three satellites are, your GPS receiver can pinpoint your location using a process called trilateration.
• Let’s see what trilateration means-  Suppose you are somewhere on the Earth with three satellites in the sky above you. If you know how far away you are from satellite A, then you know you must be located somewhere on the ‘A’ circle.
• Doing the same for satellites B and C gives you an area where the three circles intersect. This is where you are. Your GPS receiver does the same thing, using intersecting spheres instead of circles. So the greater the number of ‘visible’ satellites above the horizon, the greater the accuracy with which your GPS device can pinpoint where you are.

Please like and share my blog www.curiousknowledges.blogspot.com(❁´◡`❁)