How GPS works? -for kids

Hello kids out there ! Appreciate your curiosity in learning tech! I have written things in a very basic way, excluding deeper details. You will get to know the overall functioning of the GPS system.

So, What’s GPS?

You obviously know it’s abbreviation! Yes. Global Positioning System. GPS helps to find the location of something on globe.

Why was GPS developed?

There was a necessity to track the location of US military. So, this was first used there. Later, it’s almost used by everyone with a smartphone.

What is used in a GPS system?

For any system involving signal transmission, the two mandatory components are a transmitter and a receiver. The GPS transmitter lies in the satellites and GPS receivers are in our smart phones. There are around 30 satellites at a height of 20000 km from Earth.

What does GPS satellites do?

The transmitters in the satellites continuously send signals to Earth. The signal says, where it is and the time at which it sends it i.e. the signal contains details of the position of the satellite and the time of broadcast, which is received by the receivers in smart phone.

What does my phone do with the signal?

At any point in Earth at any time, we will receive signal from atleast three satellites or four. The received signal will have the satellite’s position and the time it was sent.

With these signals, we can find the time difference.(Time sent-Time received).Time sent comes along with signal. Time received is our phone’s time. We know the speed of the signal. All signals travel at the speed of light. Remember the basic formula to calculate distance?

distance=speed*Time.

We now got the distance between us and the satellite.

But, how does my mobile know’s its location with this distance?

Yeah, coming to the point. We are visible from 3 satellites. Meaning, we have distance from 3 satellites. With this, we can find where we are. Didn’t get it? Okay! Let’s do a simple activity. Join 3 of your friends with you. Your 3 friends are the 3 satellites. And you are the receiver who needs to find your location. Close your eyes. (Closed eyes mean, you don’t know where you are). Now stand somewhere. You will get your location without opening your eyes. I will tell you how.

1. You are standing somewhere with closed eyes.
2. Friend1 says thats you are 40meters away from him.
3. Friend2 says, you are 10 meters from him.
4. Friend3 says, you are 34 meters from him.
5. Now, you got it right? You must be somewhere matching all these 3 conditions.

This is how our phone finds the location. To be a little more techy, this principle is called the trilateration.

So kids, Got an overall idea of the working of GPS system?? Good. See you in my next blog. Bye bye. Have fun in learning !!