GPS

Why do you think GPS wouldn't work on a flat earth?

Because it's a GLOBAL positioning system. By definition, it works on a globe. To work on a flat earth, you'd need a Planar Positioning System.

Where did I claim any such thing?

Then where are, according to you, those atomic clocks that emit information about time and their own identity? How come are GPS devices, which assume they are satellites that move in specific orbits (depending on the identity information they emit), able to accurately tell their locations (and determine their own location from that)?

 I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

The GPS software you have on your phone, you can probably view the source for it, assumes it receives signals from satellites that move in specific orbits. If that weren't true, it wouldn't give correct results. In fact, it would give wildly wrong results, not just in terms of elevation.

I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

Depends exactly what you mean by “a GPS system”.

If you mean are satellites required for some kind of positioning system?  Then no.  Although accuracy and coverage would be limited due to shorter distances, distribution of transmitters, etc.  Before GPS started being added to phones, some used the network towers for a rough positioning system, but it wasn’t very good and only really worked in built up areas.

However, if you mean does the  actual GPS system require satellites?  Then yes, it does.  As others have said, the software relies on knowing the orbits of the satellites, and it’s open to anyone who wants to use it.  There’s just no way of hiding that.

Quote from: Timeisup on March 19, 2020, 07:02:21 AM

Quote from: John Davis on March 18, 2020, 08:22:24 AM

Quote from: MouseWalker on March 13, 2020, 08:36:46 PM

Quote from: John Davis on March 10, 2020, 10:33:49 AM

Quote from: MouseWalker on March 07, 2020, 08:32:10 PM

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

How do satellites orbit a flat earth? As GPS requires satellites to work.

Why do you think a GPS would require satellites to work?

Tell me then how GPS works without satellites?

It uses very good clocks. Nothing about GPS necessitates satellites in any way shape or form. All you need is a transmitter that knows where it is. It works without satellites because satellites are not necessary.

Wrong.
If we are going to approach this on a scientific basis then lets all stick to the known scientific facts. As of Aug 2019 there were 31 GPS satellites in operational orbit, with a total of 74 having been launched. That is one fact. Another fact is they are in orbit. Another fact is they can provide any user with a pretty accurate position of where they happen to be on the surface of the earth based on the earth being a sphere. They also operate taking relativity into account for the user's location.

I imagine when all those 74 satellites were all blasted off the engineers had a pretty good idea what kind of orbit they were going into, don't you agree John? As is always the case what is it about the functionality of GPS that leads you to believe the world is flat?

What about what I said is wrong?

You actually don't know. Think about it. Think about how the satellites actually orbit. In case you don't know. MEO at an altitude of 20,000Km  or so.

I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

Tell us John how would satellites be launched and orbit on a flat world. I and the rest of the planet would love to know what would actually keep them up there.

No matter if satellites are needed or can be faked, this question leads down many FE rabbit holes. Given that GPS locates you in 3 space, better questions are:

Is GPS accurate, are you where it says you are?

If your answer is yes, then taking GPS locations in several places will establish points that must be on a sphere or plane.

If your answer is no, why isn't it obvious to ship and airplane captains and car drivers that the GPS location does not match up.

Its odd to me that you think land-based transmitters won't tell you the altitude you are at. Why do you hold this quaint belief? It has nothing to do with the transmitters being in space. It has to do with how many there are.

Due to the error involved, unless they are plastered all over the place.

A transmitter directly to your side will allow a small error in the distance to result in a very large error in the height.
Lets say it is 5 km away, but it thinks you are 5 km and 5 m away.
That would be consistent with you being 224 m above a point 5 km away.

In order to provide accurate height data they would need to be very high (like in space) or there would need to be so many it isn't funny.

First off, your presumption seems to think each transmitter is at the same altitude, meaning not only a flat earth but one with no hills or valleys - oh my. Even given this absurdity, you are still wrong. They would still be able to determine the altitude.

No, in the case they are all at the same altitude and Earth was flat, how would you be able to tell if you were above them or below them?
The distance to each if you were 100 m above would be the same as the distance if you were 100 m below.
To show it even works with 4, lets assume there are 4 transmitters arranged in a square, with each side length 1 km.
You are 1 km from each transmitter. Are you above or below them?

The same situation occurs any time the transmitters you are detecting are coplanar.
And in fact, also happens in the general case when you have 1 fewer transmitters.
From a single transmitter, you have a hypershpere.
From 2, the intersection produces a sphere.
From 3, the intersection produces a circle.
From 4, the intersection produces 2 points.
From 5, the intersection produces 1 point and is overconstrained.

So until you get up to 5 transmitters you will have ambiguity in the position.

I'd like to know how he thinks it works on a round earth though, given his claim that there would be two solutions which would hold for a round earth or flat one.

If that happens with the RE, the point off in space is discarded.
The problem is with land based transmitters, unless they are all at ground level, which point should they discard?
If they are mounted 100 m high, should they discard the point at ground level or the point at 200 m?
There is no way to tell as you would want GPS to work for both.

With satellite based ones, should they discard the point at ground level, or should they discard the point potentially up to 40 000 km above the surface where the transmitters aren't even transmitting towards?


But ultimately, all of this is mute.
It doesn't matter if satellites are needed or not. What matters is the fact that they are used, and to calculate your position based upon the signals currently being transmitted you need to know the location of the satellites, which change.

There are open source GPS recievers and if you want you can just download the almanac/ephemeris from the satellites.

So you either need to have these satellites, or you need so many ground based recievers the Earth would be blanketted with them to fake the signals from the satellites for every location served by GPS.

Quote from: John Davis on March 19, 2020, 11:15:22 AM

I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

The GPS software you have on your phone, you can probably view the source for it, assumes it receives signals from satellites that move in specific orbits. If that weren't true, it wouldn't give correct results. In fact, it would give wildly wrong results, not just in terms of elevation.

Who is talking about the GPS software on my phone? The claim was that GPS can't work on a flat earth and that it can't work without satellites.

Nothing was said about any particular implementation of such a system.

Quote from: John Davis on March 19, 2020, 11:15:22 AM

I would like to know why satellites are required for a GPS system. As of yet, I have heard nothing that backs up that ludicrous claim. Its not on me to disprove unsupported statements or claims. It was the claim that a GPS would not work on a flat earth and without satellites. Is it really too much to ask for this to be backed up?

I'd like to know what support is there for the ludicrous statement that GPS is impossible on a flat earth, or the one that satellites are required for gps. As of yet, there has been nothing compelling put toward that.

Even a cursory examination of the IEEE academic database brings up hundreds of solutions that work on a flat earth and without satellites. Why is it on me to disprove someone that says complete nonsense and refuses to support it?

Tell us John how would satellites be launched and orbit on a flat world. I and the rest of the planet would love to know what would actually keep them up there.

Why would I defend something I never claimed? I mean, I can. Easily. The first time I tried you failed to understand it. The second time you broke the rules of our argument and SCG had to lock the thread.

If you mean are satellites required for some kind of positioning system?  Then no.

Thank you. I'm glad you agree that GPS does not require satellites.

Accuracy and coverage can be increased, according to previously mentioned papers, by using non-satellite tools. That was their point - to show increased reliability, coverage, and accuracy without the use of satellites. GSM also exists as markjo previously mentioned and can also leverage these techniques.

Quote from: John Davis on March 18, 2020, 10:15:09 AM

Its odd to me that you think land-based transmitters won't tell you the altitude you are at. Why do you hold this quaint belief? It has nothing to do with the transmitters being in space. It has to do with how many there are.

Due to the error involved, unless they are plastered all over the place.

A transmitter directly to your side will allow a small error in the distance to result in a very large error in the height.
Lets say it is 5 km away, but it thinks you are 5 km and 5 m away.
That would be consistent with you being 224 m above a point 5 km away.

In order to provide accurate height data they would need to be very high (like in space) or there would need to be so many it isn't funny.

Quote from: John Davis on March 18, 2020, 12:55:27 PM

First off, your presumption seems to think each transmitter is at the same altitude, meaning not only a flat earth but one with no hills or valleys - oh my. Even given this absurdity, you are still wrong. They would still be able to determine the altitude.

No, in the case they are all at the same altitude and Earth was flat, how would you be able to tell if you were above them or below them?
The distance to each if you were 100 m above would be the same as the distance if you were 100 m below.
To show it even works with 4, lets assume there are 4 transmitters arranged in a square, with each side length 1 km.
You are 1 km from each transmitter. Are you above or below them?

The same situation occurs any time the transmitters you are detecting are coplanar.
And in fact, also happens in the general case when you have 1 fewer transmitters.
From a single transmitter, you have a hypershpere.
From 2, the intersection produces a sphere.
From 3, the intersection produces a circle.
From 4, the intersection produces 2 points.
From 5, the intersection produces 1 point and is overconstrained.

So until you get up to 5 transmitters you will have ambiguity in the position.

Quote from: John Davis on March 18, 2020, 01:18:45 PM

I'd like to know how he thinks it works on a round earth though, given his claim that there would be two solutions which would hold for a round earth or flat one.

If that happens with the RE, the point off in space is discarded.
The problem is with land based transmitters, unless they are all at ground level, which point should they discard?
If they are mounted 100 m high, should they discard the point at ground level or the point at 200 m?
There is no way to tell as you would want GPS to work for both.

With satellite based ones, should they discard the point at ground level, or should they discard the point potentially up to 40 000 km above the surface where the transmitters aren't even transmitting towards?


But ultimately, all of this is mute.
It doesn't matter if satellites are needed or not. What matters is the fact that they are used, and to calculate your position based upon the signals currently being transmitted you need to know the location of the satellites, which change.

There are open source GPS recievers and if you want you can just download the almanac/ephemeris from the satellites.

So you either need to have these satellites, or you need so many ground based recievers the Earth would be blanketted with them to fake the signals from the satellites for every location served by GPS.

I'm glad you agree that satellites aren't needed for GPS.

I'm glad you agree that satellites aren't needed for GPS.

For a hypothetical system not in use, no.
For the current implementation they most certainly are.
And without satellites or extremely high transmitters you would need 1 more transmitter to establish your position.

For the original question, I would say that is focusing on the current implemenation, not some hypothetical.

Jack, this was in response to this answer to my question:

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

How do satellites orbit a flat earth? As GPS requires satellites to work.

I think we can all agree that this point is settled. Except maybe timeisup.

Jack, this was in response to this answer to my question:

Quote from: MouseWalker on March 07, 2020, 08:32:10 PM

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

How do satellites orbit a flat earth? As GPS requires satellites to work.

I think we can all agree that this point is settled. Except maybe timeisup.

I think based upon the context, at least that is still discussing the current implementation.

Where it goes downhill is this comment:

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

Because, for example, land-based "satellites" won't be able to tell the altitude you are at. Besides, there would have to be quite a few of those fake satellites to cover the whole surface of the Earth, and I don't see how it can be hidden.

Which then goes more into the fundamentals of GPS operation rather than the current system.

But we can agree that the point of a hypothetical GPS working without satellites is setttled.

That's a fair enough opinion. I was trying to understand the context at the time. I'm still not convinced that MouseWalker had any point to make except that satellites were required for GPS. Otherwise satellites orbiting a flat earth would be irrelevant.

Having been here a decade, its a misconception that comes up a lot.

I would like to point out GPS works in the ocean, far away from land.  So either the signal has to be very strong to reach the middle of the ocean, or the signal has to be transmitted from above the ground.   I dont suppose this eliminates the possibility of GPS 'balloons', but I don't see any way the signal can be strong enough to reach the middle of the ocean from ground based transmitters.

Quote

If you mean are satellites required for some kind of positioning system?  Then no.

Thank you. I'm glad you agree that GPS does not require satellites.

Accuracy and coverage can be increased, according to previously mentioned papers, by using non-satellite tools. That was their point - to show increased reliability, coverage, and accuracy without the use of satellites. GSM also exists as markjo previously mentioned and can also leverage these techniques.

That's not quite what I said.  I said that a (more limited) positioning service could be made without satellites.  But that's not GPS.  GPS uses satellites, which can be confirmed by anyone who fancies digging around in the code.

I would like to point out GPS works in the ocean, far away from land.  So either the signal has to be very strong to reach the middle of the ocean, or the signal has to be transmitted from above the ground.   I dont suppose this eliminates the possibility of GPS 'balloons', but I don't see any way the signal can be strong enough to reach the middle of the ocean from ground based transmitters.

Good point. Or at least transmitters either below the ocean or above the ground. Of course, this doesn't rule out everything but satellites. Or really a great many other options.

Do you really think it is beyond our mathematicians to find two solutions for x,y,z? Or our self learning code?

What of our engineers that build drones that kill political figures from across the world?

Quote from: John Davis on March 19, 2020, 02:11:34 PM

Quote

If you mean are satellites required for some kind of positioning system?  Then no.

Thank you. I'm glad you agree that GPS does not require satellites.

Accuracy and coverage can be increased, according to previously mentioned papers, by using non-satellite tools. That was their point - to show increased reliability, coverage, and accuracy without the use of satellites. GSM also exists as markjo previously mentioned and can also leverage these techniques.

That's not quite what I said.  I said that a (more limited) positioning service could be made without satellites.  But that's not GPS.  GPS uses satellites, which can be confirmed by anyone who fancies digging around in the code.

GPS doesn't use satellites. An implementation of a GPS might. Mind sharing what 'code' you are talking about specifically?

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

Because it's a GLOBAL positioning system. By definition, it works on a globe. To work on a flat earth, you'd need a Planar Positioning System.

Best point in the thread. Clearly the OP and the post I was responding to was not talking about the literal implementation of GPS, as that would imply a globe earth - he must have been referring to a 'global positioning system' not a "Global positioning system."

GPS doesn't use satellites. An implementation of a GPS might. Mind sharing what 'code' you are talking about specifically?

Sorry, not “the” code, any code. 

Even hobbyists can and do write their own code to make positioning apps using GPS data. Plenty of them post their codes and how they work on the interwebs.  Here’s one I found for you, that uses Matlab:

http://www.telesens.co/2017/07/17/calculating-position-from-raw-gps-data/#1a_Code_for_Calculating_User_Position_and_Clock_Bias

Of course GPS uses satellites.  They transmit the timestamp and their orbital position.   A receiver picks up the transmission, and it just takes some calculations to get a position. 

Even if you don’t want to go as far as trying to calculate your position, you could simply look at the incoming signals and see the numbers change.

Unless you want to explain how anyone can write a working GPS program that uses the position of stationary transmitters that give false and constantly changing readings of their location?  The results would be garbage.  How would no one have noticed?

So either the signal has to be very strong to reach the middle of the ocean

Stronger than it would need to be to be recieved from 20 000 km away?

Quote from: Ozymandias74 on March 19, 2020, 03:51:54 PM

So either the signal has to be very strong to reach the middle of the ocean

Stronger than it would need to be to be recieved from 20 000 km away?

Well, they would need to be strong enough that it would be easy to locate them by somebody who wants to prove the GPS is not actually satellite-based.

Quote from: Ozymandias74 on March 19, 2020, 03:51:54 PM

So either the signal has to be very strong to reach the middle of the ocean

Stronger than it would need to be received from 20 000 km away?

Possibly yes because most of those "20 000 km away" are through space with no attenuation other than the inverse square law.

GNSS frequency bands
GNSS frequency bands in the range of 1 to 2 GHz (known as L-band) are suitable for mobile satellite systems as they suffer from little rain loss and offer lower path losses. Thus, all GNSS use signals in the lower parts of L-band.

But in the 1 to 2 GHz range there is significant atmospheric attenuation even in clean air:

RF Cafe: Atmospheric Absorption (Specific Attenuation)

Atmospheric Attenuation (Specific Absorption) Chart

But it might be a "toss-up" and would depend on how close transmitters could be to the most remote areas.

Apart from this, I see no way that GNSS transmitters within a few kilometres of a flat-Earth could ever measure altitude.

Quote from: FlatAssembler on March 18, 2020, 10:12:13 AM

Quote from: John Davis on February 28, 2020, 01:28:14 PM

Why do you think GPS wouldn't work on a flat earth?

Because, for example, land-based "satellites" won't be able to tell the altitude you are at. Besides, there would have to be quite a few of those fake satellites to cover the whole surface of the Earth, and I don't see how it can be hidden.

Its odd to me that you think land-based transmitters won't tell you the altitude you are at. Why do you hold this quaint belief? It has nothing to do with the transmitters being in space. It has to do with how many there are.

They would. But they would require a lot more of them to be installed (by someone) and supervised in the whole world (including very poor or unpopulated areas). The cost of maintenance would be absurdly high. But here are some other hard parts. GPSs works on the planes. Yes, even private ones, and i don't mean board gps, i mean civil gps'. They also works in the middle of forests, mountains, where often cell network is not available. Where do they mount these magical transmitters? On the trees? Are flatties really going to defend such absurds?

Discussing the Flat-Earth Theory with Flat-Earthers is like playing chess with a penguin: you can't do it because they won't obey the rules.
I think there are basically two kinds of Flat-Earthers:
1) Those who are new here, who don't have a background in anything related to the topic, and who think "Hmm... Maybe there is something to the Flat-Earth Theory, I am not sure that it's wrong.".
2) People who aren't sincere.
Once it comes to the topics such as GPS, you see that Flat-Earth Theory is fundamentally no different from the conspiracy theories such as that the Moon doesn't exist.
And I seriously doubt any one of them have studied computer science. I mean, I have written one research paper about computer science, and I already find such claims, that GPS doesn't prove the Earth is round, very insulting. And you don't even need to have studied computer science to understand why it's wrong and insulting.

My studies were in Computer Science, Computer Engineering and Mathematics. I work for a house hold name as an engineer.

Let's see if people who are remotely knowledgeable about computer science here can form a consensus:
1) While some GPS-like systems would be possible on a flat Earth, GPS, as is currently designed (both the emitters of the signal and the receivers) can only work if the Earth is round, and the fact that GPS devices give correct results proves the Earth is round.
2) Any GPS-like system that would work without satellites (and most Flat-Earthers appear to agree satellites are impossible if the Flat Earth Theory is correct) won't be able to tell elevation while receiving signal from only three emitters, as GPS devices we have obviously can.
I consider myself relatively knowledgeable about computer science because I've written a research paper about computer science which will get published in Osječki Matematički List.

Like I said multiple times, check the IEEE academic database.

Also your baseless attacks on our knowledge are pretty fucking silly when you can't even explain your own point.