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thataway
Joined: 02 Nov 2003 Posts: 20803 City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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Posted: Mon Dec 21, 2020 10:41 pm Post subject: |
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Harvey had pointed out the limit was not 500' but 500 meters, or about 1640 feet.
Garmin's main stream of revenue is also aeronautical products, so they have a lot of experience with GPS at elevation. (2018 figures show $158 million for aviation and only $95 million for marine, $255 million for "outdoor" and $277 million Fitness and $148 for automotive/vehicular. So the marine division is the lowest revenue producer! The aviation, outdoor, Fitness and vehicular all have high elevations, and many of the hand held GPSsnow give elevation. The watch uses GPS to locate for known elevations and also barometric pressure. Heck, I have two watches (which give me elevation which is fairly accurate to a meter or so.
GPS data does have to be corrected for elevation since GPS assumes that the earth is an ellipsoid. There are random variations from that ellipsoid which have to be corrected. I think developing the database and then applying it to the GPS altimeter has been the issue. But it should have nothing to do with AIS signals... _________________ Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
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