h a l f b a k e r y
This is what happens when one confuses "random" with "profound."
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Most smartphones and many fitness trackers have built-in GPS. But
their accuracy could be better.
I'd like a kit containing two wearable GPS receivers - with bluetooth
links to each other and a smartphone (iOS or Android) running an
app to correct GPS data on the go. Data from two units even
small distance apart can be used to correct for multi-path and
other errors. Accelerometers in each unit (likewise common in
current fitness trackers and smartphones) can be used for track
Combining multiple GPS receivers to enhance relative distance measurements
[kdf, May 12 2020]
Combining inexpensive GPS to improve accuracy
[kdf, May 12 2020]
1966 Woodford/Nakamura Report
Declassified version, the good stuff is missing [kdf, May 13 2020]
[kdf, May 13 2020]
||// Data from two units even a small distance apart can be used to correct for multi-path and other errors. //
||No, it can't - not to any useful extent. You need DGPS, or a receiver in a static position with a multibird fix over a prolonged period.
||This approach has been extensively evaluated as a means of terminal guidance and rejected. It gets proposed from time to time and the fundamental math kills it again and again.
||Every now and again a vendor comes along purporting to offer a software solution but they all rely on having a minimum solid 4-bird fix with a mid-level distribution. Low obscuration (the "urban canyon" effect) always defeats it. High obscuration is not so bad but still tends to make it impractical.
||useful extent depends entirely on intended use.
Likely not useful for landing a plane. Not needed
for driving to the park. Potentially useful for
retracing your exact steps through the woods, back
to the spot where you hid the bag of ... er, the
geocache or something like that.
||Oh, and VERY appealing to moneyed geeks ... who
know EXACTLY where they were ... but want to
look at the track later and want to see it mapped
ON the trail they used, not zag-zigging dozens of
feet off to either side.
||// depends entirely on intended use. //
||"Putting a missile through Brezhniev's bathroom window" was the original specification for GPS.
||Missile guidance isn't the intended
use of this HB idea either, but I know you like that
kind of stuff. Linked some light reading for you.