[OSM-talk] Strange GPS trace - drifting?

[Andy Robinson]

Barry Crabtree wrote:
>Sent: 31 October 2006 8:43 AM
>To: raphael Jacquot
>Cc: talk at openstreetmap.org
>Subject: Re: [OSM-talk] Strange GPS trace - drifting?
>
>Thanks all. I feel happier about going round again!
>
>One other question though - is there any way to predict when this might
>happen in an area?
>
>Cheers. Baz.
>

When I need to know where the GPS sats are I use Trimble's bit of free
planning software (windows).

http://www.trimble.com/planningsoftware.shtml


Cheers

Andy Robinson
Andy_J_Robinson at blueyonder.co.uk



>
>On 10/31/06, raphael Jacquot <sxpert at sxpert.org> wrote:
>
>	Barry Crabtree wrote:
>	> Hi
>	>
>	> I've been out mapping round a local residential area. Everything
>seemed ok
>	> plenty of satellites in view, but when I look at the trace it
seems
>that
>	> over the space of a few minutes it has shifted what looks like
>about 50/100
>	> metres. I've put a screenshot of the trace at
>	> http://wiki.openstreetmap.org/index.php/Image:Grangefarm-wierd.jpg
>but
>	> haven't uploaded the gpx file because it doesn't look right!
>	>
>	> Any thoughts on what might have happened. I've been collecting
>traces for a
>	> month & this is the first time I've seen anything like this. Have
I
>done
>	> something stupid?
>	>
>	> Cheers. Baz.
>
>	no, that's relatively classic. the satellites moved between pass1
and
>	pass2...
>	your best bet is to handle the part to the right, and go over it
>another
>	day for the left part.
>	I have that pretty pronounced in the mountains. my solution is just
>to
>	go a couple times more, that eventually gives me better data.
>	of course, the real solution would be to do phase correction
>	post-calculations with two gps receivers, one fixed, one moving
>
>
>
>
>
>--
>Live as if you were to die tomorrow. Learn as if you were to live forever.
>- Gandhi.