this post was submitted on 06 Mar 2025
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204
FCC chair says we’re too dependent on GPS and wants to explore ‘alternatives’. (www.fcc.gov)
submitted 2 days ago by [email protected] to c/[email protected]
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[–] [email protected] -1 points 2 days ago (1 children)

A watch... or other simple gps device doesn't know what the elevation is.

My point, exactly

[–] [email protected] 2 points 2 days ago (1 children)

Which is why they'd need 4 satellites. Read the whole post. Read the given sources. Stop being stupid.

[–] [email protected] -1 points 2 days ago (1 children)

I did read the whole post. Stop being an asshole.

[–] [email protected] 1 points 2 days ago (1 children)

Clearly you didn't... You keep asserting false statements that have already been disproven with sources.

But ultimately it’s the same thing. You need 4 pieces of input. Either 3 satellites AND elevation. Or 4 satellites.

If a watch doesn't "know" elevation (barometer or other sensor providing such information) as the fourth data point... Then it NEEDS 4 satellites to make the data points whole. Making your statements yet again wrong. I've covered the cases... but you keep pushing false statements like "gps is triangulation" (completely incorrect) or "GPS uses 3 satellites" which is also only correct in one very specific case... Where it's largely 4 or more, with reality being more like as many satellites as the device can read the pulses for. Often being a dozen or even more...

I am making accurate and complete statements. You are the one peddling misinformation.

Hell to prove the point... my time server grabs GPS as it's primary source. It grabs up to 12 satellites to sync time. It shows me my sync status for lat/long as well... At 3 satellites it CANNOT get a lock for location OR time. At 4 it gets a weak lock.

[–] [email protected] -1 points 2 days ago (1 children)

You keep asserting false statements that have already been disproven with sources.

I don't. You just aren't paying attention to what I'm saying. You keep arguing up a strawman.

[–] [email protected] 2 points 2 days ago

You are not getting a 3 dimensional location. That’s why GPS coordinates only exist on 2 planes. You don’t know what you’re talking about.

Proven wrong, as it's a "2d" map that only exists on a 3d plane. It's a slice of space that represents the moving target of "ground level". The point that this is a problem to take it as just a "2d map" is that you can't take 3 point readings from on top of a 1000 ft cliff and 3 feet away at the bottom of a cliff and expect 3 point measurements to actually give you accurate measurements since it's just "2d" right? Elevation matters as it needs to be accounted for during the calculations.

So which coordinate accounts for elevation? Latitude or Longitude?

Where elevation = ground. As stated...

Then you assert.

It’s like you’re making my point for me.

Which was in response to a post stating that the watch would need a 4th satellite or "elevation" in order to get a valid GPS value.

And after I further clarified for you how it works... again... and that I was NOT making your point. I assumed you simply didn't understand the point I was actually making.

My point, exactly

No... It wasn't your point at all because you asserted that GPS is 3 point triangulation. When it's 4 point Trilateration which only has the option of 3 point when the fourth value of elevation is already known, which the vast majority of devices that use GPS don't know.

What have I straw-manned? Can you point to it? What part of GPS needs 4 nodes/data points is vague?