GPS Accuracy
"Meindert Sprang" wrote in message
...
"Larry W4CSC" wrote in message
...
On Tue, 27 Jan 2004 12:34:35 +0100, "Meindert Sprang"
wrote:
I have heard otherwise: A GPS derives it's speed from the doppler shift
on
the received carriers. A very slow averaging filter smoothes the
output,
which causes the delay in indicated speed. The filter is there to
prevent
erroneous speed indication due to atmospheric disurbances and
multi-path
signals.
Meindert
This might be true on some $70K sophisticated survey instrument or
other, but, here at least, our discussion is about GPS operation on a
cheaply-made piece of crap sold to the boating consumer at amazing
markups, not sophisticated electronics. What you're talking about
costs serious money. You won't find that at Waste Marine where price
isn't related to quality.....(c;
Well, the datasheet of my "cheaply-made piece of crap" GPS module, costing
a
whopping $70, clearly states the presence of doppler shift data in the raw
datastream I can extract from that module. The used chipset is a very
common
one in low end GPS receivers. Do a google search on "gps speed doppler"
and
you'll find this info.
Meindert
Tried a Google search for "gps speed doppler" and got the following message:
Your search - "gps speed doppler" - did not match any documents.
Suggestions:
- Make sure all words are spelled correctly.
- Try different keywords.
- Try more general keywords.
Also, you can try Google Answers for expert help with your search.
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