GPS spike???

In message <[email hidden]>, Dewi
<[email hidden]> writes

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Did you walk under a tree, behind a rock or cliff at that point? Almost
certainly caused by a lack of satellite signal.

See Sources of GPS signal errors on:

http://www.garmin.com/aboutGPS/

Regards
--
Neil Pugh

Bitstring <[email hidden]>, from the
wonderful person Dewi <[email hidden]> said

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Depends on the GPS you were using, but my old eTrex used to do that a
lot when it (almost) lost satellite fix - or when it got a multipath
signal from one satellite and picked the wrong version to believe.
Annoyingly the firmware in the handset refuses to go 'oops, error', and
leap back to where it should be - it drifts back piecemeal over the next
few seconds.

My 60C with an external antenna (tucked in my hat) doesn't do it but
once in a blue moon - usually when exiting from a shop or something
when it =has= lost the signal, when the first point of the new track is
fairly complete fiction.

--
GSV Three Minds in a Can
Contact recommends the use of Firefox; SC recommends it at gunpoint.

If you ring Garmin's helpline you'll be told that such things cannot happen.
No doubt they are worried about US product liability legislation/
compensation claims. But they do happen. Can be if you are close to a rock
outcrop that hides the signal momentarily. If you are out in rain and the
antenna cover gets covered with water this will also produce a spike (or
many if you are out for a long time). This can make the unit a death trap
rather than a life saver.

I've heard that mobile phone/electricity masts can also cause spikes.

Bottom line is never rely on your GPS to tell you where you are. This may be
the reason you bought it, and you may have followed the advertising blurb,
but manufacturers will not accept responsibility if you have got into
problems through relying on their units. The official line seems to be "If
you are lost get out your map and that will tell you everything you need to
know". In that case why are GPS units available?

If you have Memory Map you can remove the spike from your track quite
easily. Don't know about Anquet.

"Dewi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Cheers.

--
Dewi,

(remove spin for email)

Last month I did a 10mile route round Coniston Old Man, I've plotted a
moving track of my route on the web
(http://www35.websamba.com/lakeuk/walk.htm) using Google Maps.

You'll see that I had a few spikes appear half way through the route,
this was when I was close the a rocky hill side and view of the sky was
only really available in the west direction which I was blocking quite
abit at that point of the route - the next lot of spikes were near the
end of the journey because of tree cover.

Dave
http://lakeuk.blogspot.com

"Lakeuk" <[email hidden]> schreef in bericht
news:[email hidden]...

Quoted message said:

Last month I did a 10mile route round Coniston Old Man, I've plotted a
moving track of my route on the web
(http://www35.websamba.com/lakeuk/walk.htm) using Google Maps.

You'll see that I had a few spikes appear half way through the route,
this was when I was close the a rocky hill side and view of the sky was
only really available in the west direction which I was blocking quite
abit at that point of the route - the next lot of spikes were near the
end of the journey because of tree cover.

Wow, cool indeed. It's a pity that the satellite pictures aren't detailed.

--
Theo
www.theosphotos.fotopic.net

If you have an Etrex was it in power save mode? If so was the spike at a
point when you stopped for a few minutes?

If so this is a known feature, I think it is because when it restarts it
does not know where it is hence the spike when it is hunting for its 'new'
location.

--

Ted Ferenc
This address used is maintained only for newsgroup posting.
Mail sent there may not be read by me for several days.
"Dewi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Cheers.

--
Dewi,

(remove spin for email)

On Tue, 06 Sep 2005 08:29:00 +0100, Dewi
<[email hidden]> dropped their trousers and

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Cheers.

Thanks all for the pointers.

Geko 201 is the GPS.

It could well be that I was close to the steep side of the mountain
and the GPS got confused.

I will edit it out from Memory Map.

Cheers all.

--
Dewi,

(remove spin for email)

Bitstring <[email hidden]>, from the
wonderful person Dewi <[email hidden]> said

Quoted message said:

On Tue, 06 Sep 2005 08:29:00 +0100, Dewi
<[email hidden]> dropped their trousers and

Quoted message said:

Recently done a nice walk Capel Curig > Crafnant > Colwyd > Capel
Curig.

I noticed on uploading the route from the GPS to the PC and looking at
the route actually taken, there was a 'spike', a blip on part of the
route. I know that bit we were walking along, is straight path.

Any Ideas why there would be a 'spike'?

Cheers.

Thanks all for the pointers.

Geko 201 is the GPS.

It could well be that I was close to the steep side of the mountain
and the GPS got confused.

Yep, the Geko is noted for light weight, not for great reception under
trying conditions. You probably got a reflected signal off the adjacent
rocks ('multipath error'😉 - if your body happened to block the direct
signal at the same time, the handset suddenly sees a satellite in the
wrong place, and since it knows for damn sure where the satellite is, it
puts you in the wrong place instead. 8>.

--
GSV Three Minds in a Can
Contact recommends the use of Firefox; SC recommends it at gunpoint.

I recently had this problem on my Geko 301 whilst walking through woods
on a Chilterns hilltop. A half mile jump in one direction then
immediately back again, adding nearly a mile to the distance walked. I
happened to be looking at the screen at the time & saw all the figures
jump (giving me a whopping moving average speed figure!). I tried
retracing my steps over the same bit of path a few times but it didn't
happen again. Despite the woods I had pretty much perfect reception.
I thought it was just a one-off glitch (I've never seen it before or
since), but if others are suffering from it perhaps it's an actual bug
that Garmin need to look into.

Another glitch I occasionallally get is when I go through & zero out
previous data (eg tracklog, ascent, distance etc). If you do it too
quickly, the whole unit freezes in the ascent screen & can only be
reactivated by pulling out the batteries. Anyone else had this?

Cheers

Anth

PS. Please link to www.wheresthepath.com

Lakeuk said:

Last month I did a 10mile route round Coniston Old Man, I've plotted a
moving track of my route on the web
(http://www35.websamba.com/lakeuk/walk.htm) using Google Maps.

That's a nice one. If the satellite image resolution gets better one
day, this will be the future of all trip report sites!
--
Rudi Winter, Aberystwyth, Wales

Rudi Winter said:

Lakeuk said:

Last month I did a 10mile route round Coniston Old Man, I've plotted a
moving track of my route on the web
(http://www35.websamba.com/lakeuk/walk.htm) using Google Maps.

That's a nice one. If the satellite image resolution gets better one
day, this will be the future of all trip report sites!

It will improve eventually. Some areas already have higher resolution
satellite imagery, for example the area around Folkestone covering part
of the North Downs Way: http://www.jstott.me.uk/walks/walk.php?w=20&p=1

--
Jonathan Stott
Canterbury Weather: http://www.canterburyweather.co.uk/
Reverse my e-mail address to reply by e-mail