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crunchiespg

Does Waas Do Anything In The Uk

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as title, does activating WAAS on my gps actually do anything here in the UK?

i thought the egnos system is the euro version of WAAS but isnt active yet.

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:D I,m getting full lock and 5ft accuracy most of the time now here in Lancashire. :D

ok, so from that i take it that it is active in the uk.

 

and to fruity, what was the point?

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I checked on saturday and today... did not see the egnos bird in Berkshire, Hampshire and Wiltshire...

 

G

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No sign of WAAS or EGNOS at all yesterday down here Devon and we were out all day with my eTrax Venture turned on all day and WAAS activated on the unit.

 

The Cap Man (Keith)

 

&

 

Swallowtail (Tricia).

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No sign of WAAS or EGNOS at all yesterday down here Devon and we were out all day with my eTrax Venture turned on all day and WAAS activated on the unit.

There was on the cliffs between Branscombe and Sidmouth :D

Edited by Stuey
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Had one EGNOS bird this aft while placing a cache, suprising giving the location.

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:D Had same sort of problem in cornwall last week....phone dead,gps messing around,even next to the Earth Satalite Station?........,did consider all the satalites had fallen out of the sky,but could not find any laying around so presumed...something to do with Big Brother not wanting us to have Fun :D,
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No sign of WAAS or EGNOS at all yesterday down here Devon and we were out all day with my eTrax Venture turned on all day and WAAS activated on the unit.

There was on the cliffs between Branscombe and Sidmouth :D

We`re a little further along at Plymouth.

 

The Cap Man (Keith)

 

&

 

Swallowtail (Tricia).

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Oh bugger! Just noticed we had WAAS turned on all along. Is that extra COTM points? :D

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I dont know if the european WAAS service is fully active now, but a few years ago, I was on a survey job in Scotland and we had to rely on WAAS signals for positioning. At that time, the WAAS service was undergoing trials and was experimental (but surprisingly for an experimental system very accurate) - the only thing was that occassionally, the system was shut down over the weekends - the french scientists only worked monday to friday! I never did hear if it went fully operational, but never had to to rely on WAAS since......

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ok being dim what do i look out for on a garmin gps map 60c? to let me know when it's getting waas or egnos lock?

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ok being dim what do i look out for on a garmin gps map 60c? to let me know when it's getting waas or egnos lock?

You get little D's in the coloured bars for each satellite whose data is being corrected with Differential data from WAAS.

 

Also, if WAAS is enabled, make sure that the satellite display shows that you are at least trying to get satellites #33 or #44. If not, you might need to force a reload of the satellite almanac. I have instructions for this in German, but if you search around I'm sure it's available in English. :D

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I live near Usk in Monmouthshire and on my 60c (only had it 2 days) seem to get Waas after late afternoon and for the last 2 nights it's been showing accuracy down to 6 feet although I did diasable Waas and it still showed 6 feet! .I think tonight I will run my yellow along side the 60c and get a comparison between the two

Dave

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I was able to get WAAS in the Reading area of Berkshire last week, but I checked this morning, and the GPS is ignoring Sat 33, which is where I got my lock from last week.

 

Obviously still in testing.

 

Adrian

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Even though I have the D's displayed on the other sat bars the WAAS sats never turn from grey to solid black ,does that mean they have not achieved a proper lock ??

Dave

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Bear in mind that since the US switched off the scrambling of the GPS signals (selective availablity), receiving WAAS or not receiving WAAS should not make any noticeable difference to the accuracy of positioning.

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Bear in mind that since the US switched off the scrambling of the GPS signals (selective availablity), receiving WAAS or not receiving WAAS should not make any noticeable difference to the accuracy of positioning.

If this is the case I find it strange that more and more WAAS enabled units are being produced,even the entry level etrex has it from version 3.0.

Dave

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Bear in mind that since the US switched off the scrambling of the GPS signals (selective availablity), receiving WAAS or not receiving WAAS should not make any noticeable difference to the accuracy of positioning.

Oh yes it does! WAAS/EGNOS augments the signals from the other sats.

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Does it make a difference with caching yet?

 

Is it easier to find that tupperware with WAAS???

 

Just wondering if its worth getting a new GPS, currently using the Yellow etrex.

 

See ya...Gary

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Bear in mind that since the US switched off the scrambling of the GPS signals (selective availablity), receiving WAAS or not receiving WAAS should not make any noticeable difference to the accuracy of positioning.

Course it does! Are you suggesting that a WAAS-enabled GPS showing a "ready to navigate" accuracy of say, 9 feet is no more accurate than a none-WAAS unit showing 25 feet?

 

Edited for spelling.

Edited by leecee
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Is it easier to find that tupperware with WAAS???

Not necessarily. You could have, say 6ft accuracy, but it doesn't mean the person placing the cache did.

 

In theory, if the placer and finder both have WAAS lock, then it SHOULD make things easier. You'll still have the same problems with tree cover and placers using the wrong datum though!

 

T

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I also checked this out today (Mon) following Stuey's post a few days ago...

 

My GPSr (Venture) gave the usual 19ft accuracy with quite a good clear horizon all round (just south of Peterborough, Cambs).

I enabled WAAS and found that the accuracy then extended to 29ft or so (which was odd).

I left it for about 5 mins and then rechecked and got the magical "D"s displayed (the first ever time I had seen this), but still the accuracy was less than before WAAS was enabled.

However, a minute or two later, I rechecked and the accuracy was 6ft!

 

Also caught it saying 5ft accuracy after leaving it on top of the car for a while, but just picking up the GPSr was enough to frightening it back to a mere 6-7 feet!

It does seem to work, but you do have to give it time and as Tigger says, it won't be that much use for finding caches if someone hasn't used it to hide them in the first place.

 

Certainly a step in the right direction though!

Edited by The Klever Boys
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In a year's time this'll be too easy :P

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My understanding is there are a number of issues that mean that WAAS is of dubious use in caching and can provide false "accuracy". for example, I understand it relies on ground stations collecting GPS data and transmitting corrections to the WAAS satallites which then broadcast that to WAAS enabled recievers which use the data to "correct" errors.

 

A major component of the differential data is caused by atmospheric conditions - for example, people in Chile can get data from WAAS satallites, but as the data corrects GPS signals in the US it does not improve accuracy in South America. Unless you or the GPS unit know how relevant the data is - WAAS means nothing.

 

People have often said that having WAAS on increased accuracy, but how do they know? Have they tested this with known benchmarks, or are they assuming that if the readout says the unit is more accurate it must be? How doesa WAAS enabled GPS know it is more accurate with WAAS enabled? It can assume it is, but it can't know without knowing where the differential data is collected, how accurate it is, and how relevant it is.

 

I am not sying that WAAS does not have the potential to improve accuracy for caching - but things are much more complicated than assuming that WAAS will make things more accurate - it probably does, but it might not. As P&G have said, being WAAS enabled means nothing if the layer of the cache was not.

 

Another thing cachers often forget is that the biggest problem is tree cover- WAAS can't help with that so will tend to indicate high accuracy when there is an inherent inaccuracy that can't be corrected.

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nobby.nobbs asked what it looks like. You have to get the EGNOS satellite fairly consistently for about 5 minutes to grab the almanac. If it vanishes for a while, as it often does, it'll take another 5 minutes to receive the almanac when the EGNOS satellite comes back into range.

 

The capital Ds appear on each GPS satellite for which your GPSr has Differential error corrections. The accuracy starts to get better as more Ds appear. When you lose the EGNOS satellite for a while, the Ds start to disappear and the accuracy drifts back to normal.

 

This is a photograph taken after EGNOS satellite 33 (Atlantic Ocean Region - East) vanished and the GPSr position accuracy started to get worse.

 

ddf61778-b6a0-44c5-9d3a-264e45f09856.jpg

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Learned Gerbil -- What you say sounds entirely reasonable. I was also doubting and suspicious of the GPSr estimated error/accuracy figure. I spent some time at 5 OS trig points (known locations accurate within 1 metre) on different days. The GPSr position fix and its accuracy proved reliable. The GPSr fix was always better or equal to the accuracy figure. I am now a born-again believer in the marketing aspects of GPS accuracy.

 

You are right about the distance the GPSr is from the nearest ground station providing error corrections. If it it 4,000 miles from you then it won't be much use. If it is 50 or 100 miles then it will be of use as the GPS radio signals travel through virtually the same lump of air to get to you as to get to the ground station. This is because the GPS satellites are many thousands of miles above the earth. If they were only 10 miles up, the GPS signals would be travelling through much different lumps of air to get to you or the ground station.

 

I assume (oh dear!) that the GPSr uses smoke, mirrors and magic, to utilise the error correction data stream which originated from the nearest ground station providing error correction.

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cheers, looks like i'm going to have to try that force sat thingy as i've never got those lovley little d's

 

google search time.

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Omega 2 - I agree - the whole point is that the nearest error correction station may not be that close until the whole thing gets fully operation and in use. http://www.esa.int/images/rims_jan_L.jpg shows the full planned network of stations when everythign is up and running - you should be within about 200 miles of one of these at all times - assuming they all operate at 100% availability.

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A major component of the differential data is caused by atmospheric conditions - for example, people in Chile can get data from WAAS satallites, but as the data corrects GPS signals in the US it does not improve accuracy in South America. Unless you or the GPS unit know how relevant the data is - WAAS means nothing.

The regional variability of some components of the error, is one reason why it's a good idea to have a European version (EGNOS) transmitting European correction data.

 

In general, extra accuracy is useful (at a statistical level) no matter what the placer of the cache was doing. If the placer has a 10m accuracy and so do I, then on average the compounded error will be about 14m (square root of the sum of the squares). If my error goes down to 4m, the compounded error will go down to 12m. Not spectacular, but nice to have.

 

Also, with the increasing number of caches, within a couple of years of EGNOS finally going live, more than half the caches will have been placed using it.

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Unless you or the GPS unit know how relevant the data is - WAAS means nothing.

A correctly-functioning receiver does "know" this.

 

In parts of the far west of Ireland, it's possible to receive signals ftom the WAAS station AOR-W. (PRN122 - Garmin no 35) on a handheld.

 

This satellite provides corrections for part of the North American continent, and the western Atlantic. Ireland is not within its service area.

 

Given how the system works, we would expect our handheld to listen to signals from PRN122 for a moment, (perhaps, several moments) identify that the corrections are not applicable to its current position, and then ignore that satellite and go looking for others.

 

And - in fact - this is exactly what happens.

 

-Wlw.

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I ran my GPS Map60CS for some time yesterday in the rooflight of my den which has a reasonable view of the sky cut off to about 15° from the S, W and E and with WAAS enabled and readings taken every 15 minutes or so the coordinates varied by only 0.001 minute on each and with WAAS exactly the same. But the claimed accuracy with WAAS was 7 to 9 ft and without 16 to 32 ft. Incidentally with WAAS on the trip odometer read 0 but I am afraid I did not note the movement recorded without.

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Are you saying it was no more accurate, it just said it was? :-)

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Anyone know why my 60C only says "accuracy +/- 5m" with or without WAAS enabled? The unit seems to be functioning happily enough and often pinponits caches to with a couple of metres. I checked yesterday and the "d"s light up on the signal level meter and sat 33 was being seen.

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Had mine switched on all day and not a single D. It says 3D down at the bottom next to the battery level but no D's on the signal graph :lol:

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I used mine in Holland at the weekend and had lots of little Ds and a reported accuracy of 6 feet. Cool! :D

 

Didn't find the cache though :lol:

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I used mine in Holland at the weekend and had lots of little Ds and a reported accuracy of 6 feet. Cool! :lol:

 

Didn't find the cache though :D

LOL, it occured to me the other day that no matter how accurate my own handheld is I only stand a reasonable chance if the coordinates that it was placed with are any good! It looks like you may well have put that theory into practice :lol:

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Are you saying it was no more accurate, it just said it was? :-)

Yes precisely that - 1000th minute is good enough for me, if consistant which is what I take the claimed greater accuracy to mean.

As pointed out in geocaching it is the care taken with establishing the coords by the placer which counts as much as the use of them by the would be finder.

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I have put my gps on waas today to see if it will pick up anything and got sat 37. Which one is this. All I know was it is in the south, or was at the time..

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no matter how accurate my own handheld is I only stand a reasonable chance if the coordinates that it was placed with are any good!

Ah yes but they should have been back at least 4 times at different times of the day, taken co-ords and averaged them out!

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If this is the case I find it strange that more and more WAAS enabled units are being produced,even the entry level etrex has it from version 3.0

 

The US could switch SA back on any time! But see my later comment, there is still a demand for the ability to apply differential corrections to raw GPS data.

 

Course it does! Are you suggesting that a WAAS-enabled GPS showing a "ready to navigate" accuracy of say, 9 feet is no more accurate than a none-WAAS unit showing 25 feet?

A receiver that is not WAAS enabled, and not receiving any other differential corrections, with good satellite geometry and visibility, should in my experience currently give a position accuracy of +- 1 to 2 metres. (better than 6 feet)

 

Bear in mind that since the US switched off the scrambling of the GPS signals (selective availablity), receiving WAAS or not receiving WAAS should not make any noticeable difference to the accuracy of positioning.

 

I would suggest that in practice the improvement in position accuracy with WAAS is not noticeable to the general user.

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here's two responses i got from garmin when i asked them:

 

Your unit will not lock on to these signals because they are only test

> signals. Most newer Garmin units will have a 'Validity Flag' which reads

the

> signals and does not accept them. Some older units may accept them. Some

> signals may have 'Validity' but I would not have any information as to

> which. You will have to contact ESA about for more information on their

> satellites.

>

> You cannot use EGNOS on your unit to improve accuracy as it is not fully

> operational.

>

> Regards,

> Andy Phillips

 

and when i said but other people have been getting it:

 

Your unit will not lock on to these signals because they are only test

> signals. Most newer Garmin units will have a 'Validity Flag' which reads

the

> signals and does not accept them. Some older units may accept them. Some

> signals may have 'Validity' but I would not have any information as to

> which. You will have to contact ESA about for more information on their

> satellites.

>

> You cannot use EGNOS on your unit to improve accuracy as it is not fully

> operational.

>

> Regards,

> Andy Phillips

 

so according to them you're all lying b#%$%ds just winding me up!!!!

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thats what i thought, i didnt think egnos was active yet.

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So it's not just me then - I've been trying everything in the last week since I took delivery of my Legend to get sat 37 more than a greyed out bar with no Ds anywhere on screen. And as for sat 33 - I've never seen it - is it real or mythical?

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So it's not just me then - I've been trying everything in the last week since I took delivery of my Legend to get sat 37 more than a greyed out bar with no Ds anywhere on screen. And as for sat 33 - I've never seen it - is it real or mythical?

i get sat 33 on mine, and i get d's on most sats, but it doesnt make any difference that i can see.

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Last weekend I was up in the Yorkshire Dales (Austwick) and had 1+- meter accuracy on Sat and Sun and D’s galore. Ain’t WASS brilliant.

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Last weekend I was up in the Yorkshire Dales (Austwick) and had 1+- meter accuracy on Sat and Sun and D’s galore. Ain’t WASS brilliant.

well ive done a bit of research,and according to the official egnos site its not on yet. its only a test signal.

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well ive done a bit of research,and according to the official egnos site its not on yet. its only a test signal.

If you do a bit more research, you'll find that the definition of 'test signal' just means that it is not guaranteed and should not be relied on for anything critical. See here.

 

For those that can't be bothered reading it, the interesting bit of quote from the chap at the European Space Agency is:

 

'As you probably know, today we are transmitting a pre-operational EGNOS signal through the EGNOS test bed (ESTB). This signal is a test signal so it is not a guaranteed service signal. In reality, however, the performance of this test bed is quite good achieving accuracies of the order of 1-2m in core of Europe.'

 

T

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