How GPS works? Trilateration explained

Music:

unfa - Calmly Waiting
unfa - GPS Trip

[Unmannedair]

Trilateration only works on a surface and literally means three sides. GPS uses quadrilateration. It really isn't any more complicated. It's just more difficult to represent on a flat screen.
Your time of flight instead of representing the circle is instead a shell, the surface of a sphere. When you have 2 distances then you have 2 spheres and where they intersect is a circle instead of 2 points. Your third distance shell cuts through that circle in 2 places. So now you need a fourth distance shell in order to know which of those two places is the correct one.
If you do things like add additional distances, and look at Doppler effects then you can calculate additional information such as velocity and direction. If instead of distances you look at differences between a nearby known position and yours, then you can enhance the accuracy of the GPS by several orders of magnitude. This is initially how the military got their accurate GPS back before portable computers.

[rebeccasimpson]

Thank you. A well explained video with great graphics. I will use with my year 5 and 6 students to extend their thinking about mapping.

[unfa]

A chineese company making GPS products e-mailed me asking for business cooperation becasue of this video.

I'm a musician.

What do I do?

[NexVice]

After watching many videos, this is the only one I could understand. Thank you!

[sherrimitchell]

This is great! Using ground based positioning on a flat plane allows this to work as well and makes even more sense.

[Max-zvbu]

For those who are thinking this is a simple concept, don't forget there is Einstein's Theory of Relativity involved in calibration of the clocks in those Satellites.

[Max-zvbu]

Thank you. Great Explanation. Until now, I thought there is two way signal transmission between GPS receiver and the Satellites. Now I now the tracking actually happens by one way transmission and that is amazing.

[spruce_goose]

Thank you for a great simple explanation, for great visuals, and for sharing the animation software you used. Stellar.

[brjplummer]

A very nice graphic as shown from 2:10 onwards. The point not to be missed is that your point X could be anywhere within the reciever range of those three satelites, so therefore there are many other possible locations for you to be at. At each location when the three signals are received you will be at your own three circle cross point. Your circles will be a diferent sized circles to the one demonstrated here. So many users at slightly diferent locations all get an accurate fix. A very smart system. I loved your graphic explanation.

[youknowmonroe]

I got stuck in a game where I needed to perform trilateration, and this video got me through it. Thanks! :)

[utkarshkulshrestha]

Wonderful explanation...the complexity of this technology is so well turned into simplicity...kudos..

[richardslesinski]

This video is exactly what I was looking for to share with my physics students. Thank you.

[tarishigeetey]

thanks for helping!!! people like you make life easy a lot and keep helping

[maxbhupi]

Nice video..thank you for explaining the concept of GPS so easily

[PasseScience]

Hi, how do the satellites know their accurate position? position in which reference frame are we talking about?

[manojpaudel]

Best video about gps on youtube. Thank you.

[DaRapar]

Love your use of timeline to explain the distances.

[kerrydai]

But how does the phone calculate how much time has elapsed since the satellite has sent its signal? The phone does not have a precise atomic clock so it would not know the exact time of receiving the signal.

[MARTOUFFF]

Damn that was really nicely put, simple principle but quite effective, who would have thought ?

[SaskJiuJiteiro]

Well explained with fantastic graphics. Great video!