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Jaz666 Lifetime Member
Joined: Aug 10, 2005 Posts: 88 Location: Clitheroe, Lancs
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Posted: Sat Oct 15, 2005 10:57 pm Post subject: WAAS/EGNOS |
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Hi guys.
Has anyone in the UK ever managed to get a differential WAAS/EGNOS lock on a Quest?
Mine will often see Sats 33, 37 or 39, they'll get an almost full hollow-green bar (indicating they are trying to obtain the almanac), but it loses interest after 45 seconds and moves onto another set of satellites before coming back to 33/37/39 and getting the hollow bars again. It repeats like that.
This has been tried at the top of a 400M hilltop with a clear southern view, with the Quest aligned and perfectly still for half an hour - according to all the "WAAS/EGNOS on Garmin" websites this should be enough to get a differential lock. I couldn't even get a lock when I was on holiday closer to the equator earlier this year!
I'm thinking of borrowing a friends Etrex and taking it out with me and comparing them side-by-side to see if there's a fault with the Quest. |
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oddsock Pocket GPS Verifier
Joined: May 01, 2004 Posts: 706 Location: Monmouthshire
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Posted: Sat Oct 15, 2005 11:44 pm Post subject: |
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If you have a battery save mode make sure make sure you do not have it selected as you will not get waas lock without your gps being in normal mode.
Dave |
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Skippy Pocket GPS Verifier
Joined: 24/06/2003 00:22:12 Posts: 2946 Location: Escaped to the Antipodies! 36.83°S 174.75°E
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Posted: Sun Oct 16, 2005 1:30 pm Post subject: Re: WAAS/EGNOS |
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Jaz666 wrote: | Has anyone in the UK ever managed to get a differential WAAS/EGNOS lock on a Quest? |
Yes, lots of times. From a nearby hilltop I get a fix but it might take 5 or 10 minutes before you get the full set of differential data (you will see a D on the satelite bars).
It does do some odd things as you observe:
[quote]Mine will often see Sats 33, 37 or 39, they'll get an almost full hollow-green bar (indicating they are trying to obtain the almanac), but it loses interest after 45 seconds and moves onto another set of satellites before coming back to 33/37/39 and getting the hollow bars again. It repeats like that.[quote]
Mine does the same thing. I think it is seeing these but discounting them because they are transmitting correction data for the wrong part of the world (America).
Quote: | I couldn't even get a lock when I was on holiday closer to the equator earlier this year! |
Where were you ? Europe or America?
I was in America a couple of months ago and I was astounded to see that I got a 3D-Differential lock within a minute or two.
I am wondering if the European EGNOS system actually works as well as the American WAAS one. There was talk of EGNOS going live "real soon now" but I don't know if it ever has officially gone live or if it is still in test mode. Anyone know for sure? _________________ Gone fishing! |
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Jaz666 Lifetime Member
Joined: Aug 10, 2005 Posts: 88 Location: Clitheroe, Lancs
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Posted: Sun Oct 16, 2005 10:55 pm Post subject: |
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Today I got a D on Sat 26 for a split-second, twice. Not sure if this was a glitch, but the first time I wasn't exactly in a location with a clear sky view!
Sats 33, 37 and 39 are EGNOS birds as far as I can tell.
I was on holiday in the Med, with a perfect view south.
http://www.gpsinformation.org/dale/dgps.htm#waas explains how WAAS/EGNOS should work on Garmin units. |
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Skippy Pocket GPS Verifier
Joined: 24/06/2003 00:22:12 Posts: 2946 Location: Escaped to the Antipodies! 36.83°S 174.75°E
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Posted: Mon Oct 17, 2005 12:38 pm Post subject: |
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Jaz666 wrote: | Today I got a D on Sat 26 for a split-second, twice. Not sure if this was a glitch, but the first time I wasn't exactly in a location with a clear sky view!
Sats 33, 37 and 39 are EGNOS birds as far as I can tell.
I was on holiday in the Med, with a perfect view south. |
When I first got a GPS a couple of years ago I used to get WAAS 33 and 44 locked and 3D-Differential.
I tried it last night and it showed 44 in one slot and cycled between 37 and 39 in the other slot without ever locking on. I gave up after about 10 minutes of standing on top of a hill at midnight. I have seen 3D-Diff a couple of months ago but it took quite a while.
I don't know what's going on, I think EGNOS may be still transmitting with the "Do not use" flag set so the Garmin ignores it. I'll give my SiRF GPS receiver a try when I get a chance and see what that does.
At the present time, I can only conclude that WAAS in the UK doesn't work (on Garmin receivers anyway) and that you are better off to leave it switched off so the receiver can track 12 sats rather than 10 + 2 (useless) WAAS ones. _________________ Gone fishing! |
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