----- Original Message -----
From: "Magnus Danielson" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Saturday, November 21, 2009 4:05 PM
Subject: Re: [time-nuts] OT - GPS and North
Robert Darlington wrote:
It depends on the GPS receiver. The GPS chipset won't know (it knows
where
it is and can remember where it was to know what direction it's moving),
but
some consumer GPS receivers (Garmin, Magellan) have electronic compasses
built in. My Garmin eTrex Legend does NOT have a compass built in, but
taking about 2 steps in any direction will tell me which way I'm moving.
It
can't do this when stationary. My buddy's eTrex can point north without
moving, but that feature drains the battery faster.
The actual GPS receiver and the navigator is two different things. A GPS
navigator may use additional sensors such as accelerometers and magnetic
sensor to aid in addition to the GPS receiver built into them.
Agreed Magnus, but I dont think any gizmos are required. If the the
positions of the satellites are known, as they must be to enable the
antennas position to be calculated, I think just an extra set of
calculations is necessary to indicate the direction to anywhere else on the
planet (or elsewhere) including the geographic poles. Getting the magnetic
pole directions would need something else I suppose.
So a navigator may know, even if on a fixed location, but the GPS receiver
does not have that information.
It is important to keep these separated so that they can be discussed
properly. I don't want to say stuff like "The actual GPS receiver in the
GPS receiver...".
Cheers,
Magnus
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
