Tech Talk

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Tech Talk

Author :

N.Chokkan

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Tech Talk

(An introduction to modern technology Buzz & Gadgets for young readers)

N. Chokkan

Table Of Contents

01. GPS

02. Bluetooth

03. RFID

04. IVR

05. Blogs

06. 3G

07. Twit n’ Buzz

08. Podcasts

09. Smart-phones

10. WIFI

11. Data Mining

12. E-Book Readers

13. Tablet Computers / iPad

14. Blu-ray Discs

15. Gaming Consoles

16. LCD / LED Tv

17. QR Code

18. IPTV

19. Android

20. RSS

01. GPS

Where are you?

It is very easy to answer this question, if you are at home, or school, or playground, or inside your favorite restaurant. But what if you are in a different, unknown city? Sometimes, in a foreign country? Sometimes, inside a jungle, totally lost?

No worries, there are some cool friends to help you on this, you can't see them, but they are always circling around you, to support you when you are in such desperate situations.

But, where are they? I can't see them anywhere!

Those friends are nowhere 'near' you, But always above you, in space, silently waiting to help anytime. They are part of a network called GPS - Global Positioning System.

GPS is basically a collection of multiple satellites - Minimum 24, and a few more as spare.

These satellites are constantly orbiting earth and at any given point of time, at least three or four of them will be above us. Of course, we can't see them with our eyes, but a device called GPS Receiver can sense them and this can be used to find out exactly where we are.

How? That’s where science comes into picture, especially mathematics, geometry and physics!

First of all, let us assume you are in the middle of some strange city, and would like to know exactly where you are, and how to reach the nearest railway station.

As we observed, there are many satellites above us, and a GPS Receiver (television remote kind of a small device) in our hands can sense them accurately. This means, the GPS Receiver can find out, how far away the satellites are from the place where we stand.

For this, a simple formula is used, which you would have read in your physics classes:

Distance = Velocity * Time

Let us say the signal from the GPS Satellite travels at a velocity of 186000 miles per second, and it takes 0.08 seconds to reach your GPS Receiver. In that case, we can easily calculate the distance between the satellite and you:

186000 * 0.08 = 14880 Miles

This information is definitely useful, But not enough. Because, if you draw a big sphere keeping the satellite on the center, with 14880 Miles as the radius, we can be anywhere on that enormous sphere.

To narrow down further, we observe another GPS satellite's signals; Let us say this signal says we are 12000 Miles from that satellite.

This gives us another big sphere, with the second satellite in the center, and 12000 Miles as the radius. These two spheres will intersect as a circle, we are somewhere in that circle.

Now you know what we are going to do next, Observe yet another (third) GPS satellite and find out how far away it is from us, draw a third sphere with this satellite in the center, It intersects with the other two spheres and voila! You have found