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NigelM
Recovering Member
Does anyone know if the "Elevation" continues in 100ft increments? I'm just curious as I went over the Sunshine Skyway today and finally saw my readout jump to 100ft and then 200ft. It normally stays constantly on 0ft in Sarasota.
BTW, very cool ride!
(Now also curious if you found out what your problem was Eric?)
BTW, very cool ride!
(Now also curious if you found out what your problem was Eric?)
If it doesn't it should. I wouldn't trust GPS based altitude to better than 100ft. (It's basically due to geometry why GPS does much better at 2D horizontal measurement than it does for altitude.) A calibrated barometer does better than GPS for altitude, but I don't know if the Roadster uses one.
For what is is worth, I was charging the other day at a public charge spot, and was looking through the various menus on my Leaf's nav screen. On the GPS info screen it showed my elevation as -62 feet. I know for sure I wasn't below sea level.
Yeah, I think that is particularly notable for pilots trying to land on instruments that need to make sure they know when they are about to touch down...
Altimeter - Wikipedia, the free encyclopedia
Altimeter - Wikipedia, the free encyclopedia
NigelM
Recovering Member
Huh? That makes no sense as GPS satellites are in geostationary orbit. Your GPS doesn't stop working at night....The perils of Wikipedia!
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GPS is in medium earth orbit not GEO.
As the satellites move around you can get situations where all are near local horizon.
As the satellites move around you can get situations where all are near local horizon.
It's about to get a lot more crowded soon too.
The Galileo system will have assured "safety of life" signals that can give accurate altitude information to airliners, for example. GPS III will have similar. A tri-system receiver that can use both these and Russia's GLONASS would mean you'd almost always have satellites overhead.
The Galileo system will have assured "safety of life" signals that can give accurate altitude information to airliners, for example. GPS III will have similar. A tri-system receiver that can use both these and Russia's GLONASS would mean you'd almost always have satellites overhead.
NigelM
Recovering Member
GPS is in medium earth orbit not GEO.
As the satellites move around you can get situations where all are near local horizon.
I stand corrected! And also slightly dizzy from watching that graphic flying round.... Although I think it also proves my point as your graphic never shows less than 7 satellites visible at any one time.
For whatever reason, I think that much of the time a particular receiver may not be able to lock onto all ~7+ at once.
Maybe they only support less channels, or they found one closer to the horizon sooner, or the antenna is obstructed by something. Particularly in a car there may be some directional preference on the reception. I suppose that some of the sats are out of operation at times too.
I don't recall exactly, but I think I have noticed GPS receivers typically only using 3 or 4 at a time.
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