Basic GPS Concepts - 03 GPS codes

[@liutianyu224]

You lectures are awesome! I really wish you were my prof teaching the GNSS course lol. am gonna watch all your videos and recommend them to my peers. BIG BIG thank you

[@harrygabriel1875]

absolutely saved me for an exam tomorrow thank you so much

[@dimitardimov85]

Mrs. you are explaining very good!

[@phantomwizard]

That's Dr. to you, dim dim!

[@geosaiofficial1070]

Thank you for your lecture.It helps me a lot with my GPS subject

[@dooddirl1]

You explanation is perfect, thank you Gigi

[@othmanharon6906]

0o9m990ii¥

[@GamingAmbienceLive]

7:30 does it mean that maximum GPS lock times we can get is 50Hz? holy cow, ive been looking for this piece of information forever, and NOBODY had a clue

[@divyadevabattula3486]

lots of love from india mam......it is very useful for me tq mam.................

[@userismani]

Ammababoii...

[@ajaymalisetti5103]

1)Why don't we directly send the PRN codes ; what is the need of adding PRN code to navigation data? 2) Why BPSK modulation technique is using here ?

[@mohammedhussen690]

How are codes generated from the satellite and what gps signals look like please tell me breifly mis

[@evilrobots]

Greetings Dr. Richard. I was wondering if you could clear up how the satellite sends time correction data to ground receivers? It seems impossible for the satellite and receiver to synchronize based on the transmission from a single satellite due to the speed of light delay. I read a description of the underlying science a long time ago (mid 90s) that said the receiver is doing phase comparison of the carrier waves of pairs of satellites to determine differences in distance between the receiver and the different satellites. Combined with the ephemeris these differences enabled the receiver to determine it's own location. The author seemed authoritative and worked through the math in an example problem (which I was only able to "kind of" follow.) As I look around the Internet now, I am unable to find anyone describing the system this way. Am I crazy? Thanks in advance for any help you can give.

[@baruah1982]

kzbin.info/www/bejne/h3yUnXepntOArc0

[@evilrobots]

@@baruah1982 Thank you for your reply, but this does not really answer the question either. He begins by referring to the receiver using its range to the first SV (d1), but that's the problem. The receiver has no idea of that value. And it can't until it gets the deltaT value. The he gets to kzbin.info/www/bejne/h3yUnXepntOArc0 and says we are able to determine that. Well, he does not describe HOW we do that, and he puts it at the end, rather than the beginning. In searching further I discovered that in the technical specs GPS is described as using 'pseudorange multilateration'. Pseudorange means they are using differences between pairs of d values (d1-d2, d1-d3, d2-d3, etc.), not the d values themselves. This is apparently where the phase comparison of the carrier wave comes in. Multilateration means they are not 'triangulating' (which comes from measuring the angles) but are measuring pairs ('multi') of sides ('lateration'). I have given up on ever finding a clear description of this process on KZbin. Still, it's super interesting. Thank you again for your reply.

[@EmciGad]

Very clear! Thanks!

[@Jarrod_C]

wiat what is sv? what does it stand for, i dont think yo mentioned it?

[@gigirichard5062]

SV = space vehicle or satellite

[@ashita1130]

So good!

[@phantomwizard]

Thanks, Doc!

[@taraswara5550]

thank a lot Mrs Gigi

[@phantomwizard]

That's Dr. to you, punk!

[@ahmednor5806]

🙏🙏🌹🌹