WAAS, so what?

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Gallet
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WAAS, so what?

Post by Gallet » 22 June 07 9:02 pm

I've just updated the software on my eTrex Vista and I now find that 4 metres accuracy under a clear sky is normal in Aus. WAAS claims 3-5 metres so what's the big deal? It was about 6 -7 metres before the update.

Have the WAAS groundstations in the USA become obsolete then, or do they now give significantly better than 4 metres?

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Post by setsujoku » 22 June 07 11:12 pm

you wont be able to get WAAS reception here in oz, so i wouldnt worry too much about having it on

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Post by Slider & Smurf » 23 June 07 2:04 am

I don't believe the groundstations are obselete - there are a few more due to come online sometime in the next couple of months (northern summer). Our experience with WAAS, we were often getting down to less than 10 feet, or 2-3m. A bit better than the 4m you're now getting, but at that point we're often looking for the tell-tale pile of sticks or rocks rather than following an arrow. There are some interesting articles kicking around about WAAS history and development if you're interested in that sort of thing.

Gallet
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Post by Gallet » 23 June 07 11:45 am

GarminWebsite wrote:Basically, it's a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters 95 percent of the time.
But I'm not getting 5 times worse accuracy here in Oz. The difference between 2-3 metres and 4-5 metres is about 3 steps. Maybe important in surveying but totally irrelevant otherwise. And this must improve with the new H models which will probably track an extra satellite or three.

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riblit
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Post by riblit » 23 June 07 11:53 am

Gallet, try searching the forum for waas, you will find a bunch of earlier posts like this http://forum.geocaching.com.au/viewtopi ... light=waas

Take note of the postings by Kerry in the threads.

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Re: WAAS, so what?

Post by Damo. » 23 June 07 11:59 am

Gallet wrote:I've just updated the software on my eTrex Vista and I now find that 4 metres accuracy under a clear sky is normal in Aus. WAAS claims 3-5 metres so what's the big deal? It was about 6 -7 metres before the update.
I use Unwired for my Internet connection. The Launchpad software on my desktop to show connection strength etc got an update a little while ago.
Used to have a vertical signal strength graph which was red, yellow or green with a low, poor, good description.
The update did away with the description and colour changes. So I used to swing between red and yellow signal strength, now it's green all the time. :o
There has been no actual change in my signal strength, no new base stations put out, but the software is telling me that things have improved substantially.

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Mr Router
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Post by Mr Router » 23 June 07 12:12 pm

riblit wrote:Gallet, try searching the forum for waas, you will find a bunch of earlier posts like this http://forum.geocaching.com.au/viewtopi ... light=waas

Take note of the postings by Kerry in the threads.
If I remember Gin51E had a fair say on the matter as well :P

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Post by Gallet » 23 June 07 2:22 pm

OK, so I have to ask the obvious question.

By what means is Australia able to supply 4 metre accuracy. Was it like that in Australia say, 5 years ago?

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zactyl
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Post by zactyl » 23 June 07 2:58 pm

Gallet wrote:By what means is Australia able to supply 4 metre accuracy.
It's not, and the person who put the cache there didn't have 4 metre accuracy when they recorded the coordinates. Take the reported accuracy with a grain of salt and don't worry too much about it. :wink:

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Post by Gallet » 23 June 07 4:11 pm

@zactyl,

OK I can accept that.

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Post by Kerry » 24 June 07 12:32 pm

Gallet wrote: By what means is Australia able to supply 4 metre accuracy. Was it like that in Australia say, 5 years ago?
4 metre accuracy (even less) is possible depending on how bad you want this accuracy and how much you are prepared to pay for it.

AMSA dGPS stations are capable even though the spec is less than 10 metres, it is generally better than that BUT it is the accuracy of the reference sites that also control the end user accuracy and some of the stations are known to be not much better than 4 metres anyway.
Just a pity that most of the recreational manufacturers don't make (have dropped) differential beacon systems these days. This is a free service but limited more to coastal areas and in the relative vicinity of base sites.

Subscribe to a service like OmniStar, the better accuracy/integrity will come at a higher price. Covers the entire country but you pay for the accuracy you (think) you require.

Post process into AusPOS but comes at a cost of requiring a dual freq receiver and requires time. Not practical in terms of time required or if trying to find something dynamically.

There are other service providors but more orientated to higher accuracy requirements.

The accuracy is there if you want it but it will cost on an ever increasing scale as the accuracy requirements get into the sub metre, half metre and decimetre levels.

Really not a lot has changed in the last 5 years.

Regards, Kerry.

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Post by Gallet » 25 June 07 9:27 pm

Thanks for that info Kerry.

On a side note it has always puzzled me why maps.google give lat long coordinates down to one ten millionth of a millimetre. Call me skeptical but I don't believe it.

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Post by GIN51E » 25 June 07 11:55 pm

Mr Router wrote:
riblit wrote:Gallet, try searching the forum for waas, you will find a bunch of earlier posts like this http://forum.geocaching.com.au/viewtopi ... light=waas

Take note of the postings by Kerry in the threads.
If I remember Gin51E had a fair say on the matter as well :P
did i hear someone say WAAS :D

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Post by Gallet » 26 June 07 12:11 am

@GIN51E"

Thanks mate but I saw it (and read all the thread) the first time it was posted.

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