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Hi Robert:

Yes, every 5 years you can load the new magnetic data.
No, it requires returning the unit to a franchised dealer who updates the firmware for a charge.

Robert Eno wrote:

> So are you saying that you GPS has the capability to acquire updated
> magnetic deviation data? Is this done using a computer disk?
>
> Robert
> ----- Original Message -----
> From: Brooke Clarke 
> To: 
> Sent: Sunday, February 09, 2003 6:11 PM
> Subject: Re: GPS & Magnetic Bearings
>
> > Hi Robert:
> >
> > You're very close.  The World Magnetic Model is based on empirical
> observation, not a theory.  The model uses a 12th order
> > polynomial based on past observations.  My Motorola GPS uses flash memory
> and can be updated for a fee.  The model is much more
> > complex than just the variation (I misused deviation in the prior post),
> it has magnitudes for all three vectors North-South,
> > East-West and the largest one Up-Down.
> >
> > Have Fun,
> >
> > Brooke

   

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