You sure about that? The GPS in my car likes to tell me I'm 400 feet from where I am and going in the opposite direction
http://www.gps.gov/technical/ps/2008-SPS-performance-standard.pdf
http://www.gps.gov/systems/gps/performance/accuracy/
They actually say that "the government commits to broadcasting the GPS signal in space with a global average user range error (URE) of ≤7.8 m (25.6 ft.), with 95% probability. Actual performance exceeds the specification. On May 11, 2016, the global average URE was ≤0.715 m (2.3 ft.), 95% of the time."
And..."GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft.) radius under open sky (VIEW SOURCE AT ION.ORG). However, their accuracy worsens near buildings, bridges, and trees."
So if you happen to be under heavy tree coverage (especially if it's been raining) - or inside a parking garage - then your position can be quite a bit off. But when driving around in "normal" situations (and especially in an airplane) - these large errors should be brief.
As for the "facing the wrong direction" thing...here there is a misunderstanding. GPS DOESN'T tell you which way your facing. Navigation systems that use GPS do one of two things:
* Modern ones include a digital compass.
* Older ones rely on deducing your direction when you start moving - so they take positions every second or two and presume that you're facing in the direction you're moving.
Cellphone digital compasses have a hard time when you turn the phone upside down or sideways - and may need to be "recalibrated" once in a while (I know mine does)...but the digital compasses in cars generally don't get that kind of abuse.
So I'm not surprised you're seeing direction errors - that's not GPS.
But a 400' error is a hell of a lot. I doubt you're seeing that when driving along an open road someplace.
Check out that second link I sent you - read the bit about "Why does GPS sometimes show me in the wrong place?"
You should get around 10' precision most of the time.
Hasn't been my experience. Maybe the people who wrote those documents are trying to sell you something?
This triangle etc. thing has beed discussed before with no response from TB.
You people are obsessed
I am obsessed with following the rules of the scientific method and adhering to polite standards of logical debate, thank you for noticing.
I believe that we keep bringing back up the point of geometry because it proves that the surface of the earth can't be planar through mathematics. Tom has attempted to steer the attention away from this by using GPS accuracy as a red herring and so far refuses to debate on the rest of the proofs provided.
To briefly summarize my first post.
I established that:
1. That airline flight times are measured accurately with standardized timepieces that do not assume a globed or flat earth.
2. That flight speed can be measured accurately relative to ground speed using Doppler shift radar which also does not assume a globed or flat earth.
3. That speed is defined as Distance/Time and therefore using flight times and speeds we could algebraically solve for distance in under a 5% margin of error without assuming a flat or globed earth.
4. That the distances between the 4 cities used in the initial geometry proof are valid as aircraft speeds are tracked by both GPS and Radar which fits the initial stipulation that all data points had to be valid without the assumption of latitude and longitude accuracy.
Doppler shift radar is accurate within 1% margin of error in measuring flight speed over both short and long distance.
At this point, unless there is a way to disprove the existence of time, distance or speed then we have met all of Tom Bishop's demands and would like him to address it fully. It is geometrically impossible for the earth to be flat. It must be either concave or convex and based on my casual observance, it's not concave.
GPS accuracy, quite frankly, doesn't matter in this proof. It doesn't invalidate the other device used to track flight speed.
Tom, Tsunami and any other flat earth believers are welcomed and encouraged to engage me in any portion of my hypothesis and research other than GPS accuracy. I have politely and faithfully met all of the other demands placed upon this proof. It is mathematically impossible for the earth to be flat.
Thank you,
CriticalThinker