[StinkyOne]

Third option: You're not as tech-literate as you think you are and you fallaciously assume that GPS data is the only dataset used in mobile phone location tracking. You're attributing the efficacy of big data and very recent developments in fingerprinting to a rather simple system that's been conceived of 40 years ago. Round or flat, that ain't how it works.

None of that is relevant. There are handheld GPS devices that work far out of the reach of cell phones. I've used them when hiking in remote areas. Very accurate.

Enjoy this website that tracks shipping traffic via satellite. Not GPS, but still relevant as it is a global positioning system provided via satellite.
https://www.marinetraffic.com/en/ais/home/centerx:-12.0/centery:25.0/zoom:4

[pablozablo]

It kinda-sorta-maybe works, except when it doesn't. That is the central point....

What about my Garmin GPS watch? I can see it is incredibly accurate because the route it shows me on the map is exactly where I know I've been. Doesn't connect to Wifi, no phone signal, doesn't even have Bluetooth activated. Is it just luck?

[AATW]

As someone who's been using actual GPS for geotagging my photographs, I have developed an intuition of just how much one can expect from it. I'd encourage you to do the same.

OK. So, basically, you don't think GPS is that accurate. Other people are saying it is.
Whatevz. Honestly, I don't care. The fact is GPS is a thing and it works. You say yourself you use it.
The central point is not how accurate it is or whether iPhones use GPS data alone.
The central point in the context of FE vs RE is that GPS works using a series of satellites which orbit the globe. Ergo, we live on a globe.
If you have any evidence to the contrary then I'd be interested to hear it.

[Pete Svarrior]

What about my Garmin GPS watch? I can see it is incredibly accurate because the route it shows me on the map is exactly where I know I've been. Doesn't connect to Wifi, no phone signal, doesn't even have Bluetooth activated. Is it just luck?

Presumably. Your experience contradicts that of my own and virtually everyone I've spoken to about the subject. It also contradicts the technical specification of GPS.

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS - most of the tracking data unsurprisingly seems to come from 9-dof accelerometer/magnetometer units. This, of course, resolves the contradictions you've just raised.

[Science, bitch!]

Could we now please proceed to the essential part of my question?
My intention was not to spark a debate about the accuracy of GPS, and I deliberately left open whether those systems rely on satellites (which obviously I and most fellow round-earthers have no reason to doubt) or something else like ground-based radio beacons like some flat-earthers claim.

What I was getting at was why flat-earthers think it reasonable to claim that NASA and other space agencies are not aware of the shape of earth.

FES Consensus seems to be that NASA and other space agencies fake space travel out of greed, but aren't actually aware that the earth is flat.

However, to develop and operate GPS and similar systems, whether using satellites in space or radio beacons on earth, somebody obviously needs to be pretty aware of earth's actual shape.

GPS is operated by US Air Force. Does this mean the USAF knows earth is flat but didn't tell NASA?

GLONASS is operated by Roskosmos, Russia's space agency itself and Galileo is operated by ESA (European Space Agency). How is that possible without them knowing the earth is flat?

[inquisitive]

What about my Garmin GPS watch? I can see it is incredibly accurate because the route it shows me on the map is exactly where I know I've been. Doesn't connect to Wifi, no phone signal, doesn't even have Bluetooth activated. Is it just luck?

Presumably. Your experience contradicts that of my own and virtually everyone I've spoken to about the subject. It also contradicts the technical specification of GPS.

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS - most of the tracking data unsurprisingly seems to come from 9-dof accelerometer/magnetometer units. This, of course, resolves the contradictions you've just raised.

GPS receivers do exactly what they say, they provide an accurate location from orbiting satellites.

Please explain the contradiction.

[xenotolerance]

Here is another, way better source: http://fellrnr.com/wiki/GPS_Accuracy. The author overlays GPS route plots onto maps, compares a bunch of different devices, and goes into some detail about how the technology works.

point is, it does

[pablozablo]

Presumably. Your experience contradicts that of my own and virtually everyone I've spoken to about the subject. It also contradicts the technical specification of GPS.

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS - most of the tracking data unsurprisingly seems to come from 9-dof accelerometer/magnetometer units. This, of course, resolves the contradictions you've just raised.

So if it doesn't need GPS, why does Garmin bother saying it does? And if it demonstrably does (but not just) use GPS, are you conceding that GPS works? What's the point of GPS that doesn't work? Why would that even exist? To whose material benefit? It can't be for profit as any competitor could come along with their product and say "Look! Our product is just as accurate as Garmin's, is cheaper and doesn't rely on GPS!" and they'd clean up.
Accelerometer and magnetometer combined cannot deliver the accuracy. This is nonsense.

Anyway, back to the OP - good luck with getting a straight answer.

[StinkyOne]

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS - most of the tracking data unsurprisingly seems to come from 9-dof accelerometer/magnetometer units. This, of course, resolves the contradictions you've just raised.

One glaring issue - I can remove the battery pack, go somewhere, replace the pack, power up and wait for the unit to receive location data. It shows me almost exactly where I am. Accelerometers can only detect inertial changes. They can only track changes in motion, not tell you where you are. You can keep trying to obfuscate, but you have no factual leg to stand on.

[inquisitive]

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS - most of the tracking data unsurprisingly seems to come from 9-dof accelerometer/magnetometer units. This, of course, resolves the contradictions you've just raised.

One glaring issue - I can remove the battery pack, go somewhere, replace the pack, power up and wait for the unit to receive location data. It shows me almost exactly where I am. Accelerometers can only detect inertial changes. They can only track changes in motion, not tell you where you are. You can keep trying to obfuscate, but you have no factual leg to stand on.

and tracking data in terms of location and track will use GPS, your movement will use the accelerometer/magnetometer.

[Tumeni]

What about my Garmin GPS watch? I can see ....

Presumably. Your experience contradicts that of my own and virtually everyone I've spoken to about the subject. It also contradicts the technical specification of GPS.

Which aspect of the Garmin's operation contradicts which part of the 'technical specification' of GPS, in your mind?

That said, even a quick Google search reveals that your Garmin watch almost certainly does not just use GPS ...

What would it take to make you absolutely certain, not just 'almost' ... ?

[Scroogie]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

Your proof of that statement is - Where?

Instead of spending your time trolling the net for cherry picked instances which seem to fit your viewpoint, if you wish to make an attempt at discrediting GPS, why not put your esteemed "Zetetic Principle" to good use and do a little first hand observation? Grab your GPS (not a phone, but a REAL GPS receiver), hit the road and test its accuracy against known positions and known distances while out for a Sunday drive to a favourite picnic spot? Then come back here and report its serious inaccuracy for all of us to witness.

[Tom Bishop]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

Your proof of that statement is - Where?

See the link I provided. People attempted to determine their distance and they could not.

[StinkyOne]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

Your proof of that statement is - Where?

See the link I provided. People attempted to determine their distance and they could not.

In the link you provided, the first paragraph is:
Recreational GPS units are useful for giving reasonable accuracy in location, giving elevation and tracking overall pace. Recreational GPS units are not suitable for providing accurate total distance covered. The mileage on the odometer, if you will, is often on the higher side.  As much as 10% in some cases.

So you admit that RECREATIONAL GPS devices are reasonably accurate at giving location, elevation and speed readings, but tend to over report distance traveled? So what you're saying is that GPS works and even cheapo models do an alright job of giving location? Cool, welcome to the round Earth.

It is important to note the recreational part of the story. The GPS signal doesn't 'tell' you where you are. The device has to calculate it. Cheaper devices aren't going to be as accurate.

[Science, bitch!]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

Your proof of that statement is - Where?

See the link I provided. People attempted to determine their distance and they could not.

Several people including myself have conclusively explained to you why the phenomena described in that article you linked are irrelevant to this topic.

What I conclude from your refusal to accept that is, you're just messing with us and don't actually believe what you say.

[Scroogie]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

The word wrong is an absolute. If my GPS determined the distance from my house to the grocery store to be 6.002356 miles and I were somehow able to determine that the actual distance was 6.002355 miles, then I could say that my GPS was wrong. It was pretty damned accurate, but wrong nonetheless. This tends to make yours a null statement, in that it provides no real information regarding GPS accuracy.

I will certainly agree that my GPSs are never spot on, but, given that they are all consumer level devices, I am almost always impressed with their level of accuracy, normally well within 5 meters and very often within 2 or 3 meters.

[Treep Ravisarras]

As someone who's been using actual GPS for geotagging my photographs, I have developed an intuition of just how much one can expect from it. I'd encourage you to do the same.

I have used an actual GPS in my aircraft for descending to earth, at night and in cloud, with mountains around me. This is scary, but used by many privately owned aircraft every day, as well as the 'big' airlines.

The use of GPS, without any secondary source of navigation, is allowed by the national aviation authority and their reasoning for it is that:
GPS derived position accuracy is currently stated to be 100m or less, 95% of the time, and 300m or less, 99.9% of the time.
So they have designed their routes and approaches to airports, descending through mountains, based on this criteria, with an additional margin obviously for instrumentation errors, piloting errors etc.
Their main interest is the safety of the general public, which we are all grateful for.

People attempted to determine their distance and they could not.

FWIW this makes your point arguing at the margins, as people (in planes) determine their distance from mountains every day by use of GPS and they all survive to do it again ... the next day.

[inquisitive]

Nice rationalization there, but those explanations have not been demonstrated to be true. All we know is that GPS is wrong when attempting to determine distance.

Your proof of that statement is - Where?

See the link I provided. People attempted to determine their distance and they could not.

You need to understand that GPS gives an accurate position and distance is determined by software which uses the position data.

[Tumeni]

See the link I provided. People attempted to determine their distance and they could not.

One more time;

"A GPS-based calculation on a consumer-grade device of an "as the crow flies" distance between two points differs from that recorded by someone taking a path, on foot, between them (not necessarily keeping to a straight line). Big whoop."

As the poster says above, the calculation of the distance between points is not a function of the GPS system, it's done by software using that data. Claiming the software's result is 'wrong' does not equate to GPS itself being 'wrong'.

[Pete Svarrior]

Which aspect of the Garmin's operation contradicts which part of the 'technical specification' of GPS, in your mind?

Not the operation itself. I'm willing to assume that the watch operates correctly. It's the accuracy of the statement that I severely doubt, for reasons explained immediately prior and afterwards.

What would it take to make you absolutely certain, not just 'almost' ... ?

Nothing - unlike RE'ers, I always accept the possibility that I might be mistaken. But to increase my confidence: the model of the watch would be a good start. Their documentation seems reasonably available, so that should easily let us confirm my suggestion. That said, I haven't found any Garmin watches which rely solely on GPS.

are you conceding that GPS works?

I thought I made myself perfectly clear. For a particularly low standard of accuracy, GPS works. That's why it's usually used as supplementary data in positioning systems.

Allow me to remind everyone that the key contention here is whether GPS works well or not. Not whether or not it exists. Accounts along the lines of Stinky's "I used it and it almost told me where I was!" are unlikely to swing it in either direction.