How does GPS work?

This video explores the technicalities of how Marine GPS units can calculate position wherever you are in the world.

In this video, GPS means the system developed by the USA called NAVSTAR GPS. Other Global Satellite Navigation Systems are available.

GPS is used by merchant ships, navy ships and pleasure boats as a way on finding position at sea. As a navigator, it is important that you know how GPS actually calculates position so that you know when it is feeding you false information.

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[ptsdon]

The video provides a good simple illustrations and a good description of how GPS works. The narration of the video is really high quality. The accompanying article, "How Does Marine GPS Work?", mentioned in the video (link provided) provides a concise document that corresponds to what is covered in the video. Casual Navigation also provides another article, which is a great tutorial on navigation, "What is a nautical mile and why is it used?". Look for the link at the end of the article mentioned above. In my opinion, all three are well worth the investment in time.

[videosandshorts]

This is the best explanation of gps technology.

[stevencolborne]

As a gps software engineer, this is very good. It may be beyond explaining how but r.t.k. gps receivers can achieve accuracies less than a quarter inch. Making them useful for survey applications..

[AuroraNora]

7:34 This is slightly wrong. *Special* Relativity says that the satellite clocks run SLOWER due to relative speed.

However, *General* Relativity says that the satellite clocks run FASTER because they experience less of Earth's gravity. The gravity effect is far greater than the speed effect, and so the satellites have a net gain in clock speed.

[maneebmasood]

The best GPS video. Summarizes many topics under the GPS quite brilliantly.

[quelorepario]

The relativistic time dilation is not only due to the speed (you've got that backwards), but also from the gravitational potential (it is farther away from the earth, with less influence from Earth's gravity). Search about *gravitational time dilation*.
Literally, you head is literally getting older faster than your feet.
The speed actually would make the clock to slow down (the faster you travel, the slower the time passes, compared to the rest), but the gravitational potential wins (the farther you are from the source of gravity, the faster it goes), so the net effect is that the time in the satellite goes faster than the Earth.

[brimstonebrimstone]

I stumbled on to your videos and found them extremely interesting. I subscribed to your channel and look forward to seeing all your videos. You do a great job at explaining things visually and verbally! Keep up the great job you're doing.

[ciCCapROSTi]

FYI: if you see a clock running FASTER than your own, that's not due to speed. Special relativity is symmetrical, as motion is relative, every observer thinks they are standing still. So every observer sees other objects' clocks running at the same speed (when stationary relative to them) or slower (when moving in some direction). The faster clocks come from being farther up from the gravity well, which is general relativity.

[SantanderDiogenes]

Excellent video! I would include: With only 1 satellite the position will be within the surface of a sphere. With a second satellite, the position will be within the intersection of 2 spheres; that is, a circle. With the 3rd satellite the position will be within the intersection of the circle and the sphere; that is, 2 points. With the fourth satellite you will have a unique possible position. More satellites will increase accuracy.

[dexter]

I have searched every video on YouTube for GPS but this one is best excellent explanation good voice and animation very easy to understand keep it up bro

[glypnir]

Since you're a pilot, it would be interesting to know if you use any special GPS equipment. I watched a video on piloting in the Houston Ship Channel, and the pilot brought on his own high quality GPS system and attached it to the ship. Then it was related to the position on the ship and the specific dimensions of the ship, so they had a very accurate representation of the exact position of the ship in the channel. They've got really tight space restrictions in the most inshore end of the channel. It's also one of the relatively rare navigable non military places that no unauthorized boats or ships are allowed in the US. The combination of the narrow confines and the strategic significance of all those oil processing and loading facilities mean that there's a big sign, as well as protective measures to prevent any non-authorized vessels from going there. There is a free tour I'd like to take sometime.

[nolmaoo]

Not reall was looking for anything just got interested in one of your videos and now I’m stuck here listening to explanations of boats and signals
The best part is that is casual and the edits are simple

[yogeshregmi]

this is the best video i have ever seen on gps technology

[rohitjadhav]

Such a good explanation man.
Thanks a lot. It was very helpful.👍

[helenmadeleinecraft]

very helpful, and the explanation was very clear.

[jacktonish]

Best GPS video explained i'v seen on youtube. THANK YOU SIR, APPRECIATE IT.

[TobyAsE]

The relativistic error comes mainly from the theory of General Relativity, the sattelites are further out of the gravity well that is the earth and therefore their clocks run faster compared to our clocks on (or near) the surface.

[postwar]

Excellent presentation: direct, progressive, and with clear graphics. As an operator, I needed to get a handle on the 'nuts and bolts' of how it works. Thank you. Very well done.

[aliarikan]

you doing very clear explanations ... keep up the good work ..

[mariorammelmuller]

Congratulations on 10k subscribers! YT just recommended one of your videos and you had exactly 9999 subscibers so I thought might as well be your 10000th subscriber :)