GPS?

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GPS?
« on: February 27, 2019, 01:48:34 PM »
I saw something on the FAQ page here which seems a bit odd. Maybe it's just a typo?

On the FAQ page it says that GPS works by referencing landmarks. I'm sure someone put that in by mistake, because of course GPS doesn't have anything to do with landmarks. It measures changes in radio wave signals from different directions. Then it uses simple math to triangulate the receiver's position based on those signals.

Maybe the radio signals don't come from outer space, but wherever they do come from that is how GPS determines location. I'm an electronics engineer and would be happy to explain in detail how all the components in a GPS receiver or your phone actually do work. But in any case, it would be great if the owners of the website corrected the misstatement about GPS in the FAQs.
"The problem with quotes on the Internet is that it is hard to verify their authenticity." Abraham Lincoln

Re: GPS?
« Reply #1 on: February 27, 2019, 02:02:21 PM »
The explanation of GPS is what you found objectionable in the FAQ?

Re: GPS?
« Reply #2 on: March 02, 2019, 02:43:57 AM »
Well he has given a point that resonates with him (pun intended). Just like Rab and many others do here.

What is telling in all of this is that nothing seems to have changed in the FAQ despite all the errors being repeatedly pointed out.

Re: GPS?
« Reply #3 on: March 03, 2019, 01:48:48 PM »
The FAQ is "The Answer" when a FE is replying to a post with a one liner. "Why didn't you look in the FAQ? The answer is in the FAQ!" WHen an error is pointed out, the FAQ becomes "just some possibilities, it clearly states none of the answers are certain, therefor need no defense.

"It needs some work, but no one has fixed it lately." The problem is they are too busy with breakthrough discoveries or just lazy, not that an accurate FE FAQ is impossible.

It is a brilliant system for those who don't include consistency checking in their analytical technique. FEs, Trump supporters, tribal authoritarians. The answer you need to support your tribal beliefs despite reality. Be happy, agree with your friends, and never have to contemplate an idea that invalidates your cherished belief.

I can't do it, I'm stuck with reality even when I don't like it.
Is it possible for something to be both true and unproven?

Are things that are true and proven any different from things that are true but not proven?

Re: GPS?
« Reply #4 on: March 03, 2019, 02:16:43 PM »
I am a software engineer, never worked at gps, but I understand math, physics, and the software process.

GPS works by transmitting messages with the exact time (four atomic clocks). The receiver has a clock (less good than atomic, but good enough) and subtracts to get the time the signal took to reach the receiver. The receiver computes the distance from the time difference and that, with the satellite location, makes a geometric sphere. Do the same with a second satellite, and the calculated spheres will intersect in a circle. Third satellite and the three spheres intersect at two points, fourth sphere, intersection is one point -> your location.

Here is one explanation, there are many, just google "how does gps work?"

https://electronics.howstuffworks.com/gadgets/travel/gps3.htm

If the FAQ says something else, it is wrong, the FAQ may well be wrong according to itself, so that fits.

You can get a gps receiver and free software to display satellites and locations, here is one:

http://www.visualgps.net/#visualgpsview-content

If you think the people who wrote that are NASA conspirators (there are many such programs, all conspirators?) and the program is not what it says it is, you can go to sourceforge.net and search on "gps receiver". You will find open source software gps programs that take raw signals from a usb gps receiver, convert to messages, and calculate your location. If you can read the source code, you can see the exact thing they do, compile the program yourself, and see everything. Buy a $25 usb gps receiver and step through the program, look at the data, confirm the calculations. You will have to know C++, the ones I looked at were C++, maybe there is a java or ???, but this sort of thing is usually C++.

There is an FE here who thinks it is possible to fake the signals without satellites and get just small errors that would be unnoticed. I say 1. it would be noticed, and 2. if not theoretically impossible, doubt that anyone knows how to solve the technical problems and even if they did, the expense and complexity would be immense (and noticeable). But at least this explains why gps receivers and software could be worldwide and looked at by many without them knowing that gps satellites do not exist.

Occam's razor: the true explanation is the simplest. GPS satellites exist and work the way they say. Anything else gets insanely complicated.
Is it possible for something to be both true and unproven?

Are things that are true and proven any different from things that are true but not proven?