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Date: Wed, 8 Oct 1997 08:33:17 -0600 (MDT)
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From: Nate Williams <nate@mt.sri.com>
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To: Mike Smith <mike@smith.net.au>
Cc: Nate Williams <nate@mt.sri.com>,
        cliff ainsworth III <cliff@cliffsworld.com>,
        freebsd-hardware@freebsd.org
Subject: Re: project truck.....ideas wanted 
In-Reply-To: <199710080501.OAA00853@word.smith.net.au>
References: <199710061833.MAA01027@rocky.mt.sri.com>
	<199710080501.OAA00853@word.smith.net.au>
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> > > GPS might be useful depending on the length of the run; I suspect that 
> > > its basic accuracy won't be good enough to give you useful figures.
> > 
> > Actually, GPS is *very* accurate.  If you really want to do GPS, setup a
> > stationary unit, and use the data collected from it.  You can get better
> > than 1-meter accuracy that way (differential GPS.)
> 
> Damn, I forgot DGPS.  You will want a decent wireless radio link 
> between the truck and your base station to run the DGPS data (from 
> memory the Rockwell modules want 9600 bps) over.  A relatively cheap 
> shorthaul wireless modem set should give you enough to run PPP over.  
> You could use this for realtime telemetry.  8)

You don't even *need* a wireless radio link, since the GPS unit will
allow you to synchronize your clocks with the satellites, thus allowing
you the ability to use time-stamps for your readings that you can
'differentialize' after the run.

> > > Watch out for fifth-wheel speed recorders; they have a tendancy to 
> > > disintegrate under severe conditions.
> > 
> > Not only that, they tend to slow you down. :)
> 
> This is when they're working, or after they've become small rototillers 
> dragging clumps of the roadway behind you? 

Both, although the latter tends to provide much more friction, but for a
shorter period of time until it disintigrates! *grin*


Nate