Dude, this is so bad. "Using some engineering techniques, the satellites measure the distance between you and the satellites." You're literally propagating the single worst misunderstanding of how GPS works in that sentence and several other times after that. The satellites don't measure anything. This is so bad that you should really pull the video and redo the audio here so that at no point are you stating or implying that the satellites "know" where individual receivers are. Make it clear that they are beacons, similar to lighthouses. Ships use lighthouses at known positions to find themselves. GPS receivers use the beacons in space to find themselves. I think I have to unsubscribe on principle.
This video is false, first off satellites dont exist, we don't live on a ball earth, Albert Einstein equations and bull shit explanations don't prove anything it is false.
New Technology is you're going to translate this, do not translate it directly. The audio implies that the satellites know something about the distance to the receiver. This is false and should not be repeated.
Levent YÜZGEÇ the necessary timing accuracy requires that the signals are both all processed on the same chip, meaning that signals received from the phone's modern would be out of sync. Further, the multiplexed nature of the cell phone signals adds extra timing errors. The entire point of putting the navigation beacons in space is so that it wouldn't be necessary to have huge numbers of beacons on the ground that covered smaller areas.
Hi, I'm a viewer from Poland. I've actually finished translating your movie into my native language. Adding different types of subtitles will most likely increase the possibilities of reaching more viewers. I would like to add subtitles in Polish, I plan to translate the next films. I really like your way of spreading knowledge. Best wishes.
This video is so much wrong. It implies that the satellites "know" something about the location of the receiver. This is horribly bad, and is the most common misunderstanding of GPS. After watching this video, you probably know slightly less about GPS than you did before you watched it.
As you correctly said: "Mobiles and other receivers has no atomic clocks so they are not accurate as the atomic clocks integrated into the satellites. So a 4th satellite is used to eliminate this limit and monitor the other 3" And thats all!! Remember that even the atomic clocks are devices and their performance is subjected to the variation of environmental conditions especially temperature and pressure. Physicists frequently tend to ignore this "detail". So as you correctly said tiny measurement variation lead to huge error calculation when the speed of light is get involved. All is needed here for error compensation is CALIBRATION and is achieved through the 4th satellite and other calculations in advance regarding the clock of the satellites on the earth and in orbit. GR is certainly correct and improved nowadays thanks to more accurate measurements and has predicted many fenomena such as light bending and the existence of black holes, but is not required to make GPS to work properly. It is amazing (and disappoing) how much stuff is out there claiming still this GPS + GR correlation. It is also a pity that some very good physics science channels on youtube spread this idea.
Thank you for not forgetting about general relativity, many people (even teachers) only talk about special relativity when explaining how GPS works. They remember the influence of speed but forget the acceleration of gravity.
I see alot of time offset confusion so I hope this helps. If we assume there is no time offset, then the fourth satellite will give us a fourth sphere which given the time offset will probably not intersect at the same point as before (since all these spheres assume time offset to be 0). Lets assume the real time offset is T which we want to find and lets say that our assumption of time offset is t where we initialise t=0. One can see that the new distance to each satellite is d = (t2 - t1 - t) * c since we assume a shift of t that is initially 0. If we increase t then the distance decreases on all spheres (and sphere sizes shrink). Likewise we can decrease t then that causes all sphere sizes to increase. Mathematically we can use this to determine the value for t at which all four spheres intersect at a point (well precisely at 2 points but we can pick the one near the earth's surface). This is how the fourth satellite solves time offset.
would have been even better with an explanation of autocorrelation, since GPS signals are too weak to be conventionally 'received' like an ordinary radio broadcast
I guess I got the answer, Let's assume you have three satellites and the exact precise time is unknown to the GPS receiver , let that actual precise time be T, the signal received from satellites shows times T1, T2, T3, so now the distances will be c*(T1 - T) , c*(T2 - T) , c*(T3 - T) now just imagine if we vary T, there will only be "some" values on which the Equations (equations of three spheres intersecting at a point) will converge to single solution, turns out if you have 4 satellites (4 spheres) there will only be "one" value of T that will converge to a single solution. Hence problem is solved, this also means that GPS receiver can be used as an excellent time keeping device by simply calculating T.
@@anilaxsus6376 I think triple sat with a certain deltaT_offset will give you a location. Keep the same deltaT_offset, then remove one sat in the triple with the fourth one, and calculate again, might give you another location. Since you can only be at one location, all you need is adjust the deltaT_offset so that both give you the same location.
exactly! no logic here... I "guess" (and only guess, as the video does not explain the reasoning) that the 4th satellite is to make the predicted location more accurate, since the point all the spheres have in common can be narrowed down even further, so we can ignore the points predicted by the wrong time having device to a more likely one. But again, no idea, it is not explained.
finally ı find a video explains gps tech and relativity. i watched almost 5 videos which are talking about farmers and some people says how far from a city
They actually had issues with Einstein's equations and started using a standard doppler shift. Farm tractors using GPS were impractical until they went with a standard doppler shift equation, instead of Einstein's botched equations, now GPS is a common place for farm tractors. The original idea of relativity was that it be a doppler shift between moving reference frames, Einstein did the math improperly. GPS now ignores his equations, utilized a standard doppler shift, and the system improved greatly, giving the potential for robotic tractors and self-driving cars now. If we had stayed with the relativity equations of Einstein, self-driving cars would be next to impossible. th-cam.com/video/j1Pe8y74Avg/w-d-xo.html
@@JoeDeglman If Einstein was wrong, then explain gravitational lensing. Or black holes. Or gravitational redshift. Ya know, the most basic of things that General Relativity predicted and scientists have since proven to be real phenomena?
@@jaykay4137 Oh wow, you have proved black holes? Or gravitational lensing/redshift are real world problems? Einstein peaked at E=Mc² Bud. Relativity is just him ramming time (an abstract) into Maxwell's equations and dropping the mic. How hip. The problem is predictions. Theo.Phys sucks on that idea like a desperate junkie, or a wannabe saint and that's where it departs from real Science. Your 'proofs' are just copies of ideas stolen from a bible: the graphs and generated images of multiverses and worm holes are the new stained glass windows, the attack on Philosophy and Free Will are 'proof' of a deeper understanding... May you live long enough to see the proof of Gravity - it's the compounded unused attractive force currently attributed to electrons - first one who proves it gets a Nobel. Or you can write the still missing 'Proof of Relativity' but that's crazy talk right? No the world is not flat. Yes, we did land on the moon.
@@jaykay4137 Right an excellent question. Astrophysicists are observing that dispersion happens in space, but only through matter and not through space devoid of matter, also through what is known as ISM interstellar medium, AKA an atmosphere, indicating that light bends through and atmosphere, not vacuum of space. Here is Dr. Dowdye who agrees that "gravity" cannot bend light, and the Shapiro effect is not caused by curvature of space but requires an atmosphere. It is the Sun's atmosphere that does the bending, like a rainbow is dispersion and bending through an atmosphere. th-cam.com/video/CnvOybT2WwU/w-d-xo.html In fact Dr. Dowdye shows that Einstein's equations fail to predict the bending at any other distance from the Sun, as Einstein's formulas predict, and Einstein works only at the plasma brim where there is an atmosphere. So effectively Einstein came up with an equation that describes the math from known light bending at the time, but it only works at 1 solar radius where there is an atmosphere. So Einstein got part of the math for the observed bending right by observation, but every where else his equation fails. In fact the Sun bends light at 1.75 arc seconds. The Earth at sunrise, or during an eclipse, bends light through its atmosphere at 30 arc minutes. That over 1000 times the bending of light caused by the Earths atmosphere vs the sun. If Einstein is right then the Earth bends space more than the Sun. Definition of dispersion...… The separating of frequencies of sound waves or light by frequency when the energy wave travels through a medium or atmosphere. This causes the lower frequencies of light to arrive first followed by the higher frequencies. AKA the Shapiro effect is not due to general relativity or space curvature, but an atmosphere. In fact they are seeing dispersion from quasars and from fast radio bursts, indicating that light, contrary to mainstream opinion is travelling as an energy wave like sound does through air, but when light travels through matter in space, to cause the bending and the Shapiro effect. Sound also produces dispersion of the frequencies when it travels through metals or diffracts around objects. There is no such thing as gravitational lensing or gravitational redshift, but the effects are real, just not caused by curvature of space, but by an atmosphere and requires the presence of matter, which general relativity says does not exist in the vacuum of space.
@@JoeDeglman seems like you're quite jealous of Einstein. There must be some reason that he is still considered as the greatest scientists of all time. May be there are some errors in his theories but you're describing him as he hadn't done anything in the field of science. C'mon man is there anything personal??????
It's similar to receiving a television signal with an antenna. Your GPS device receives the signals and does all the work by itself. The satellites only broadcast.
At 5:35, the video states, "at an altitude of 20,000 km above the earth, the satellites experience one quarter of the earth's gravity." Is that correct? The radius of the earth is about 6,400 km, so the satellites are about 26,400 km from the center of the earth, or about 4 times as far from the center as someone on the surface of the earth (26,400/6,400=4.125). Doesn't the force of gravity vary by the square of the distance between two masses? So, wouldn't the satellites experience only 1/16 of the earth's gravity (assuming that "the earth's gravity" means the force of gravity experienced at the surface)?
You get a bunch of satellites in various orbits circling the earth transmitting their atomic corrected time, satellite number and calculated position to earth. You receive these signals with an antenna. A computer collects the data, compares the time differences with position of the satellites and can calculate the distances between the satellite and the antenna by using the speed of light across time difference. With the known position of three or more satellites, it can calculate our longitudinal, latitudinal and altitude on earth with triangulation (simple math). Atmosphere can bounce these signals and slow the signals, so it uses many satellites to increase accuracy. The military used to shift the time on the satellites periodically to make it difficult for consumers to utilize the technology for obtaining position data any closer than within 100 meters, which was post correctable by overlaying collected GPS data by a surveyed antenna. These days are gone, but at any time can be reimplemented in a time of war. You will then discover how quickly GPS can be disabled globally. A coronal mass ejection has the ability to fry satellites in orbit as well, which is why we should never take for granted the ability to locate ourselves on earth by old fashioned means. Technology is great to have but should not be trusted as being the only way to collect position data. The day cars, planes and boats rely 100% on GPS to navigate is when Murphy's law comes back to remind us when planes fly into the ground and cars collide with things globally when this occurs.
i have done a lot of work on GPS devices since 1996. i think this is a good video, but there are some bugs in the video. 1. the 3D positioning requires 4 satellites. it cannot be done just 3 satellites. 2. the timing synchronization between the user device and GPS system is done by this way: the device SW manipulates 4 distances with 4 satellites with a initial device clock pre-setting, if the 4 satellites signals not aggregating into one point, it means its clock has error, then adjusting the device clock and manipulating again, till they are aggregated into one point. at this moment, the device clock is synchronized with the GPS system clock. 3. the cell phone station can help the device to find its location and what satellites are above its head, to help the device SW to pre-setting its clock more close to really GPS system clock. this can reduce the time (from 30 seconds to 3 seconds) for the device SW to manipulate and synchronizes its clock with GPS system clock. without the cell phone station, the device doesn't know where it is, especially you just arrive a new city by a flight, its SW could estimate a totally wrong location to start, that causes the SW take a lot of time to manipulate its location to adjust its clock, even - or + the clock in wrong direction. hope my words could give some little help.
1:34 - You're saying, "the satellite knows you're somewhere at this location". The satellites don't know where any GPS receivers are, because the receivers aren't transmitting anything back to the satellites.
@@AnmolSingh-rf3zt Maybe, but the receiver (the thing you hold in your hand) doesn't send anything back up to space, is what I'm saying. The satellites communicate with each other and some operator ground stations - but there is no two-way communication between the sats and the end users. It's the receiver that does all the time calculations, and outputs your location.
The intersection of two signal spheres coming from two satellites gives a circle. The GPS receiver should be somewhere in this circle. The intersection of this circle with the surface of the signal sphere of the third satellite gives 2 points. However, the explanation presented in video talks about the intersection of circle with signal sphere of the third satellite and not the intersection of circle with the surface of signal sphere of the third satellite.
I actually understood everything discussed. Excellent video. Though you didn't discuss additional satellites tracking a location and what that does. Greatly improved triangulation?
I'm sure I'm missing something otherwise I would not ask this: 3:54 if your phone knows the time offset, then why not just broadcast it (or embed in the computation) so there won't be a need for a fourth satellite to pinpoint you?
Right! Then to think there is RTK GPS now days that can get down to consumer grade one centimeter accuracy/precision in the size of a cell phone or less.
@@wonniewarrior Still do! I usually don't need a compass... though even like using the navigators, I don't and use notes I make regarding the route to the destination address after searching online maps or print maps. I have always had a compass on my dash in my trucks... though didn't in the last car yet. For radio direction finding though I still use a compass.
The speed of light through space is a constant. However, you do bring up a good point as light speed does slow down as the radio signal moves through the atmosphere. The biggest impact delaying the signal at the frequencies GPS uses is when it passes through the Earth's ionosphere. There are corrections applied to the time delay of arrival of the GPS signal to account for the ionospheric refraction of the signal. This is one of the largest sources of errors in GPS, but still only meters after estimated corrections are applied.
The satellites do not calculate your location, your GPS receiver does that instead. And you also left out another effect that GPS must also compensate for-the rotation of the Earth and the effect it has on electromagnetic signals, known as the Sagnac effect.
Relativity explains why my GPS navigator reads 30 ft accuracy when moving at 60 mph, and 1 ft accuracy when stopped. The navigator's clock is in fact moving fast enough to have such an error.
Let's assume you have three satellites and the exact precise time is unknown to the GPS receiver , let that actual precise time be T, the signal received from satellites shows times T1, T2, T3, so now the distances will be c*(T1 - T) , c*(T2 - T) , c*(T3 - T) now just imagine if we vary T, there will only be "some" values on which the Equations (equations of three spheres intersecting at a point) will converge to single solution, turns out if you have 4 satellites (4 spheres) there will only be "one" value of T that will converge to a single solution. Hence problem is solved, this also means that GPS receiver can be used as an excellent time keeping device by simply calculating T.
@@vedant6633 Excellent! One can imagine the first three spheres defined from measuring distances to three satellites intersecting in a point. However, when one measures the distance to the fourth satellite, the new sphere doesn't quite intersect at that point. One can try various guesses as to the error in your local clock, which moves all the spheres around a bit. One can iterate the guesses at your local clock error until all four spheres intersect in a single point. Now you know both your x, y, z location and your local clock error. Or you can just solve the 4 equations in four unknowns without all the iterations. :)
Can you be one of our patron? www.patreon.com/LearnEngineering . I will truly appreciate that.
Couldn't these mobile phones receive signals from the base station? Now they get the signal directly from the satellite?
Dude, this is so bad. "Using some engineering techniques, the satellites measure the distance between you and the satellites."
You're literally propagating the single worst misunderstanding of how GPS works in that sentence and several other times after that. The satellites don't measure anything.
This is so bad that you should really pull the video and redo the audio here so that at no point are you stating or implying that the satellites "know" where individual receivers are. Make it clear that they are beacons, similar to lighthouses. Ships use lighthouses at known positions to find themselves. GPS receivers use the beacons in space to find themselves.
I think I have to unsubscribe on principle.
This video is false, first off satellites dont exist, we don't live on a ball earth, Albert Einstein equations and bull shit explanations don't prove anything it is false.
New Technology is you're going to translate this, do not translate it directly. The audio implies that the satellites know something about the distance to the receiver. This is false and should not be repeated.
Levent YÜZGEÇ the necessary timing accuracy requires that the signals are both all processed on the same chip, meaning that signals received from the phone's modern would be out of sync. Further, the multiplexed nature of the cell phone signals adds extra timing errors.
The entire point of putting the navigation beacons in space is so that it wouldn't be necessary to have huge numbers of beacons on the ground that covered smaller areas.
Hi, I'm a viewer from Poland. I've actually finished translating your movie into my native language.
Adding different types of subtitles will most likely increase the possibilities of reaching more viewers. I would like to add subtitles in Polish, I plan to translate the next films.
I really like your way of spreading knowledge.
Best wishes.
Please for the love of GOD, never stop these videos. They are so detailed and visually appealing to watch!
Flat Earth Believer
@@HelloHello-rw6cx lol how am i a flat earth believer?
@@Limeayy Believer of God 🤣
@@HelloHello-rw6cx You do drugs btw?
@@Limeayy 🖕 you and only you
Think about it how amazing this is even people who don't understand or know about Theory of relativity are also able to use GPS like a pro...
I really like a content like this, where you bring things all around us into educational perspective. Keep it up bruh
Asifali
Best channel on TH-cam 💐💐
It's ironic that flat-earthers use GPS to get around.
@eternal footman conspiracy conspiracy theory lol
@eternal footman ok sir
@eternal footman what are the real conspiracy theories ?
@eternal footman And this psyop has been ridiculously effective, it's hilarious and sad to see.
many years ago there is video on youtube explaining gps is not using satelit but using shortwave radio frequency
Absolutely amazing explanation. Great video
Thank you so much! I already knew most of this, but this is the only source I've found that explained the solution to the time-offset.
1:54 Oh wow! Some one standing in the arctic's with just a half t-shirt!
Lol
Wow u explain such complexity with ease
The whole world fitting in a smartphone screen.
Is really nice video we use too 3d in our video Congratulation
GPS is a fantastic engineering topic. I absolutely love this channel.
This video is so much wrong. It implies that the satellites "know" something about the location of the receiver. This is horribly bad, and is the most common misunderstanding of GPS.
After watching this video, you probably know slightly less about GPS than you did before you watched it.
Well I think he made it clear that the GPS satellite ,broadcasts it's time globally and is not a receiver..
The content on this channel is amazing and extremely easy to comprehend, thank you
I use GPS every single day! I can't imagine how did we travel without GPS? It was so complicated!
I guess it was quite interested tho. Having your compass and following the stars' and sun's guidance. That's super adventurous 😁
People had been traveled around the world even when GPS hasn't been found yet
Eienstien with cigar.... Just too awesome
You don't explain how the fourth satellite helps solve the time offset equation.
I agree
it's just math and you can do that .
four equations four unknowns x,y,z, toffset. x,y,z are coordinates of your location
distance=(t1-(t2+toffset)).c
I think this will help your device to get the atomic clock time as your device don't hv atomic clock
4 unknowns and 4 equations (1 for each sattelite)
As you correctly said: "Mobiles and other receivers has no atomic clocks so they are not accurate as the atomic clocks integrated into the satellites. So a 4th satellite is used to eliminate this limit and monitor the other 3"
And thats all!!
Remember that even the atomic clocks are devices and their performance is subjected to the variation of environmental conditions especially temperature and pressure. Physicists frequently tend to ignore this "detail".
So as you correctly said tiny measurement variation lead to huge error calculation when the speed of light is get involved.
All is needed here for error compensation is CALIBRATION and is achieved through the 4th satellite and other calculations in advance regarding the clock of the satellites on the earth and in orbit.
GR is certainly correct and improved nowadays thanks to more accurate measurements and has predicted many fenomena such as light bending and the existence of black holes, but is not required to make GPS to work properly.
It is amazing (and disappoing) how much stuff is out there claiming still this GPS + GR correlation. It is also a pity that some very good physics science channels on youtube spread this idea.
Amazed! to see theory of relativity application in everyday use.
Thank you for not forgetting about general relativity, many people (even teachers) only talk about special relativity when explaining how GPS works. They remember the influence of speed but forget the acceleration of gravity.
Scientists and engineers are so smart. Thank goodness for them. I’m already lost one minute into this videos
Relatively speaking, you can always ask one of your smarter relatives
Thank you for such a amazing animated series of such a complicated topic. Than you so much to whole team!! 😊
Thanks for the knowledge. I didn't knew about the time error and Theory of general relativity involved in GPS system.
Its amazing technology. It's crazy that it was started way back in 1973.
I see alot of time offset confusion so I hope this helps. If we assume there is no time offset, then the fourth satellite will give us a fourth sphere which given the time offset will probably not intersect at the same point as before (since all these spheres assume time offset to be 0). Lets assume the real time offset is T which we want to find and lets say that our assumption of time offset is t where we initialise t=0. One can see that the new distance to each satellite is d = (t2 - t1 - t) * c since we assume a shift of t that is initially 0. If we increase t then the distance decreases on all spheres (and sphere sizes shrink). Likewise we can decrease t then that causes all sphere sizes to increase. Mathematically we can use this to determine the value for t at which all four spheres intersect at a point (well precisely at 2 points but we can pick the one near the earth's surface). This is how the fourth satellite solves time offset.
It is explained in this video.
th-cam.com/video/CMSCgAxDASc/w-d-xo.html
Thank you for clearing that point.
The video did not explain very well
Wow Theory of Relativity is used in GPS - E= MC 2 - Einstein Equation Vera Level 👍👍👍👍👍👍
Thank you for this technology 🙏
would have been even better with an explanation of autocorrelation, since GPS signals are too weak to be conventionally 'received' like an ordinary radio broadcast
We need to solve your time offset.
Oh so how do we find that?
More satellites!
What??
I guess I got the answer,
Let's assume you have three satellites and the exact precise time is unknown to the GPS receiver , let that actual precise time be T, the signal received from satellites shows times T1, T2, T3, so now the distances will be c*(T1 - T) , c*(T2 - T) , c*(T3 - T) now just imagine if we vary T, there will only be "some" values on which the Equations (equations of three spheres intersecting at a point) will converge to single solution, turns out if you have 4 satellites (4 spheres) there will only be "one" value of T that will converge to a single solution. Hence problem is solved, this also means that GPS receiver can be used as an excellent time keeping device by simply calculating T.
@@vedant6633 I feel like you are making sense but I still don't understand
@@anilaxsus6376 I think triple sat with a certain deltaT_offset will give you a location. Keep the same deltaT_offset, then remove one sat in the triple with the fourth one, and calculate again, might give you another location. Since you can only be at one location, all you need is adjust the deltaT_offset so that both give you the same location.
exactly! no logic here... I "guess" (and only guess, as the video does not explain the reasoning) that the 4th satellite is to make the predicted location more accurate, since the point all the spheres have in common can be narrowed down even further, so we can ignore the points predicted by the wrong time having device to a more likely one. But again, no idea, it is not explained.
@@MyJapaneseLifeif we had deltaT = 0(let's say by using an atomic clock), then we could find our location only by using a single satellite.
Thank you for the informative video about GPS
finally ı find a video explains gps tech and relativity. i watched almost 5 videos which are talking about farmers and some people says how far from a city
Actually, i am new for this concept of satellites. i really wondered by your explanation with real time explanation. Really Great Work sir.
This channel is doing an amazing job.thanks a ton.
Fantastic, thank you, well explained
It is real happy to see that mathematics is used in real world applications too 😇
This guy knows where he's GOING with his channel
Get it?😉... GPS, he knows the direction.
Great explanation
Very very nice video sir.......
Best explanation ❤❤
Well done, extremely well detailed, you've explained things that have never been explained in my school, and made it fun to watch too.
Fantastic Explanation!
This is one of my favorite learning channel. Thank you.
thank you for this amazing video
I could never imagine relativity is so important to us
They actually had issues with Einstein's equations and started using a standard doppler shift. Farm tractors using GPS were impractical until they went with a standard doppler shift equation, instead of Einstein's botched equations, now GPS is a common place for farm tractors.
The original idea of relativity was that it be a doppler shift between moving reference frames, Einstein did the math improperly. GPS now ignores his equations, utilized a standard doppler shift, and the system improved greatly, giving the potential for robotic tractors and self-driving cars now. If we had stayed with the relativity equations of Einstein, self-driving cars would be next to impossible. th-cam.com/video/j1Pe8y74Avg/w-d-xo.html
@@JoeDeglman If Einstein was wrong, then explain gravitational lensing. Or black holes. Or gravitational redshift. Ya know, the most basic of things that General Relativity predicted and scientists have since proven to be real phenomena?
@@jaykay4137 Oh wow, you have proved black holes? Or gravitational lensing/redshift are real world problems? Einstein peaked at E=Mc² Bud. Relativity is just him ramming time (an abstract) into Maxwell's equations and dropping the mic. How hip.
The problem is predictions. Theo.Phys sucks on that idea like a desperate junkie, or a wannabe saint and that's where it departs from real Science. Your 'proofs' are just copies of ideas stolen from a bible: the graphs and generated images of multiverses and worm holes are the new stained glass windows, the attack on Philosophy and Free Will are 'proof' of a deeper understanding...
May you live long enough to see the proof of Gravity - it's the compounded unused attractive force currently attributed to electrons - first one who proves it gets a Nobel. Or you can write the still missing 'Proof of Relativity' but that's crazy talk right?
No the world is not flat.
Yes, we did land on the moon.
@@jaykay4137 Right an excellent question. Astrophysicists are observing that dispersion happens in space, but only through matter and not through space devoid of matter, also through what is known as ISM interstellar medium, AKA an atmosphere, indicating that light bends through and atmosphere, not vacuum of space. Here is Dr. Dowdye who agrees that "gravity" cannot bend light, and the Shapiro effect is not caused by curvature of space but requires an atmosphere. It is the Sun's atmosphere that does the bending, like a rainbow is dispersion and bending through an atmosphere. th-cam.com/video/CnvOybT2WwU/w-d-xo.html
In fact Dr. Dowdye shows that Einstein's equations fail to predict the bending at any other distance from the Sun, as Einstein's formulas predict, and Einstein works only at the plasma brim where there is an atmosphere. So effectively Einstein came up with an equation that describes the math from known light bending at the time, but it only works at 1 solar radius where there is an atmosphere. So Einstein got part of the math for the observed bending right by observation, but every where else his equation fails.
In fact the Sun bends light at 1.75 arc seconds. The Earth at sunrise, or during an eclipse, bends light through its atmosphere at 30 arc minutes. That over 1000 times the bending of light caused by the Earths atmosphere vs the sun. If Einstein is right then the Earth bends space more than the Sun.
Definition of dispersion...… The separating of frequencies of sound waves or light by frequency when the energy wave travels through a medium or atmosphere. This causes the lower frequencies of light to arrive first followed by the higher frequencies. AKA the Shapiro effect is not due to general relativity or space curvature, but an atmosphere.
In fact they are seeing dispersion from quasars and from fast radio bursts, indicating that light, contrary to mainstream opinion is travelling as an energy wave like sound does through air, but when light travels through matter in space, to cause the bending and the Shapiro effect. Sound also produces dispersion of the frequencies when it travels through metals or diffracts around objects.
There is no such thing as gravitational lensing or gravitational redshift, but the effects are real, just not caused by curvature of space, but by an atmosphere and requires the presence of matter, which general relativity says does not exist in the vacuum of space.
@@JoeDeglman seems like you're quite jealous of Einstein.
There must be some reason that he is still considered as the greatest scientists of all time. May be there are some errors in his theories but you're describing him as he hadn't done anything in the field of science.
C'mon man is there anything personal??????
This is such a GREAT video! Thanks!
Great explanation 👌🤝
Great work 🙏👏👏👏🔥
well explained! Thank You..
THANKS FOR THIS VIDEO !
GREAT EXPLANATION !
This is truly an achievement of human civilization
What impresses me the most is that those 24 satellites can handle everyones smart devices at the same time
It's similar to receiving a television signal with an antenna. Your GPS device receives the signals and does all the work by itself.
The satellites only broadcast.
@@slowanddeliberate6893 that makes perfect sense, thanks
@@amnesiai On second thought, I might be wrong.
@@slowanddeliberate6893 No, you were exactly right!
Excellent work .
Thanks So much for This excellent video.
I like how we applay physics laws to invent such a impressive system like GPS .
Thank you for such a wonderful explaination
Amazing video! Thanks for the wonderful work put onto this.
best explanation ever!
At 5:35, the video states, "at an altitude of 20,000 km above the earth, the satellites experience one quarter of the earth's gravity." Is that correct? The radius of the earth is about 6,400 km, so the satellites are about 26,400 km from the center of the earth, or about 4 times as far from the center as someone on the surface of the earth (26,400/6,400=4.125). Doesn't the force of gravity vary by the square of the distance between two masses? So, wouldn't the satellites experience only 1/16 of the earth's gravity (assuming that "the earth's gravity" means the force of gravity experienced at the surface)?
it is clear and short. Thank you.
You get a bunch of satellites in various orbits circling the earth transmitting their atomic corrected time, satellite number and calculated position to earth. You receive these signals with an antenna. A computer collects the data, compares the time differences with position of the satellites and can calculate the distances between the satellite and the antenna by using the speed of light across time difference. With the known position of three or more satellites, it can calculate our longitudinal, latitudinal and altitude on earth with triangulation (simple math). Atmosphere can bounce these signals and slow the signals, so it uses many satellites to increase accuracy. The military used to shift the time on the satellites periodically to make it difficult for consumers to utilize the technology for obtaining position data any closer than within 100 meters, which was post correctable by overlaying collected GPS data by a surveyed antenna. These days are gone, but at any time can be reimplemented in a time of war. You will then discover how quickly GPS can be disabled globally. A coronal mass ejection has the ability to fry satellites in orbit as well, which is why we should never take for granted the ability to locate ourselves on earth by old fashioned means. Technology is great to have but should not be trusted as being the only way to collect position data. The day cars, planes and boats rely 100% on GPS to navigate is when Murphy's law comes back to remind us when planes fly into the ground and cars collide with things globally when this occurs.
When he was drawing the circles for 2D trilateration, I had flashbacks to drawing earthquake epicenter lines in earth science class, good old days..
Ooh that's great to hear. I've downloaded a geometry ebook recently to brush up my spatial skills.
Super video and best channel
i have done a lot of work on GPS devices since 1996. i think this is a good video, but there are some bugs in the video.
1. the 3D positioning requires 4 satellites. it cannot be done just 3 satellites.
2. the timing synchronization between the user device and GPS system is done by this way: the device SW manipulates 4 distances with 4 satellites with a initial device clock pre-setting, if the 4 satellites signals not aggregating into one point, it means its clock has error, then adjusting the device clock and manipulating again, till they are aggregated into one point. at this moment, the device clock is synchronized with the GPS system clock.
3. the cell phone station can help the device to find its location and what satellites are above its head, to help the device SW to pre-setting its clock more close to really GPS system clock. this can reduce the time (from 30 seconds to 3 seconds) for the device SW to manipulate and synchronizes its clock with GPS system clock. without the cell phone station, the device doesn't know where it is, especially you just arrive a new city by a flight, its SW could estimate a totally wrong location to start, that causes the SW take a lot of time to manipulate its location to adjust its clock, even - or + the clock in wrong direction.
hope my words could give some little help.
Amazing explanation! Thanks
I love this channel 💜
1:34 - You're saying, "the satellite knows you're somewhere at this location". The satellites don't know where any GPS receivers are, because the receivers aren't transmitting anything back to the satellites.
But it recieves data of t1 and also notes the t2.
Only these two variables are required for radius/distance
@@AnmolSingh-rf3zt Maybe, but the receiver (the thing you hold in your hand) doesn't send anything back up to space, is what I'm saying. The satellites communicate with each other and some operator ground stations - but there is no two-way communication between the sats and the end users. It's the receiver that does all the time calculations, and outputs your location.
GPS dont work in UK, Alaska and russia. They say it self on television
@@rottendamned Maybe not in Russia, to favor GLONASS. There's no reason GPS shouldn't work in UK and Alaska.
@@ojkolsrud1 and the reason is!!!! Im stupid i dont know. Why will cops lie on television!
WOW.....now i will keep my mobile phone GPS more correct......i under stand how it works....
Flat Earth
great video. thank you
My boy explained it well :)
Wow... Great information.. Thanks
The intersection of two signal spheres coming from two satellites gives a circle. The GPS receiver should be somewhere in this circle. The intersection of this circle with the surface of the signal sphere of the third satellite gives 2 points. However, the explanation presented in video talks about the intersection of circle with signal sphere of the third satellite and not the intersection of circle with the surface of signal sphere of the third satellite.
I actually understood everything discussed. Excellent video. Though you didn't discuss additional satellites tracking a location and what that does. Greatly improved triangulation?
Global Coverage
Very nice video . Thank you
Greatly understood.😁
Dude I am a EEE student all your videos help me thanks
Thanks for your hard work for this amazing video
I'm sure I'm missing something otherwise I would not ask this: 3:54 if your phone knows the time offset, then why not just broadcast it (or embed in the computation) so there won't be a need for a fourth satellite to pinpoint you?
Thank you, it was very essential contents of video lecture
Anyone still remembers the struggle: map in one hand and compass in the other? 😀😀😀
Jack Sparrow knows, Savvy😁
Actually it's Captain, Captain Jack Sparrow! 😋
Right! Then to think there is RTK GPS now days that can get down to consumer grade one centimeter accuracy/precision in the size of a cell phone or less.
Or driving with a map on your knees, or even map draped over steering wheel. Oh the wild past we lived in.
@@wonniewarrior Still do! I usually don't need a compass... though even like using the navigators, I don't and use notes I make regarding the route to the destination address after searching online maps or print maps. I have always had a compass on my dash in my trucks... though didn't in the last car yet. For radio direction finding though I still use a compass.
A very good video !
3:47 are there any explanations on how those crystal clocks work?
Wow
Theory of relativity
Finally practical
Hats off you sir, thanks for this knowledge
Great one
Finally theory of relativity got its application ⛹⛹⛹lol
Thank you for sharing.
Muy bien explicado. Good video, thank you!
Tengo un mihor explicasion para ti. SaludosTiera Plana. But I prefer English. or...or .. or ..
Thanks. Useful, interesting video
Thanks, well explained !!
Great video. Very fun to watch even though I’m super baked rn.
Thank you very much , great work... There is other videos about telecommunication. Thanksssssssss
It's good video 😊😊
Thank u for this important informations
How does the 4th satellite solve the timing issue?
This video explains it clearly.
th-cam.com/video/CMSCgAxDASc/w-d-xo.html
Just a question, speed of light is not a constant. It is affected by cloud, moisture, air density, etc. How do they take that into account?
The speed of light through space is a constant. However, you do bring up a good point as light speed does slow down as the radio signal moves through the atmosphere. The biggest impact delaying the signal at the frequencies GPS uses is when it passes through the Earth's ionosphere. There are corrections applied to the time delay of arrival of the GPS signal to account for the ionospheric refraction of the signal. This is one of the largest sources of errors in GPS, but still only meters after estimated corrections are applied.
Awesome channel!!!!!
The satellites do not calculate your location, your GPS receiver does that instead.
And you also left out another effect that GPS must also compensate for-the rotation of the Earth and the effect it has on electromagnetic signals, known as the Sagnac effect.
WoW great video
Relativity explains why my GPS navigator reads 30 ft accuracy when moving at 60 mph, and 1 ft accuracy when stopped. The navigator's clock is in fact moving fast enough to have such an error.
How is the phone's time offset calculated using the fourth satellite?
4 linear equation 4 variables simple
I have the same question :) I guess using 4 equations to solve for 4 unknowns in this context could be a separate video.
Let's assume you have three satellites and the exact precise time is unknown to the GPS receiver , let that actual precise time be T, the signal received from satellites shows times T1, T2, T3, so now the distances will be c*(T1 - T) , c*(T2 - T) , c*(T3 - T) now just imagine if we vary T, there will only be "some" values on which the Equations (equations of three spheres intersecting at a point) will converge to single solution, turns out if you have 4 satellites (4 spheres) there will only be "one" value of T that will converge to a single solution. Hence problem is solved, this also means that GPS receiver can be used as an excellent time keeping device by simply calculating T.
Yes, I think by using algebra.
@@vedant6633 Excellent! One can imagine the first three spheres defined from measuring distances to three satellites intersecting in a point. However, when one measures the distance to the fourth satellite, the new sphere doesn't quite intersect at that point. One can try various guesses as to the error in your local clock, which moves all the spheres around a bit. One can iterate the guesses at your local clock error until all four spheres intersect in a single point. Now you know both your x, y, z location and your local clock error. Or you can just solve the 4 equations in four unknowns without all the iterations. :)
I love these animations so bad
I thought GPS requires internet connection....😅
BTW great video!👍🏻
No, A GPS can be used in the middle of the desert or ocean with no internet connection for thousands of miles!