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Old 10 May 2004, 08:06   #11
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Hi Tim

Yes I understand how GPS & WAAS works, which is not disimilar to the old differental GPS but without a second receiver.

I have done some digging with some of my contacts (I am a design engineer with a company that designs GPS, GSM & GPRS technology) and can report the following.

WAAS IS ACTIVE, but only as a test signal.

The signal is present but not sending data which can be used for navigation yet.

This means that GPS's will report the presence of WAAS but will not increase their accuracy yet !.

This is not reported much as at present WAAS adds nothing.

Hope this clears thing up.

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Old 10 May 2004, 08:34   #12
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So, if WAAS is present as a test signal - will garmin pick up egnos instead? or is a software update/ change to UK spec away from WAAS required.
Seems to be a lot of confusion - maybe just mine!
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Old 10 May 2004, 14:30   #13
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Quote:
WAAS IS ACTIVE, but only as a test signal.

The signal is present but not sending data which can be used for navigation yet.

This means that GPS's will report the presence of WAAS but will not increase their accuracy yet !.
glad we both agree on that then, so when do your sources say EGNOS is coming on line , and good point raised do we need a software update.
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Old 11 May 2004, 04:38   #14
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I'm not sure if this is correct or just chinese whispers but I vaguely remember hearing that having WAAS switched on but not receiving a signal can actual degrade the accuracy of the normal GPS signal. Hence if there is no signal it is better to run with it switched off.

Additionally something I know is correct is that WAAS will not work if your unit is in battery save mode (im guessing this only affects handheld units).

Cheers

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Old 11 May 2004, 08:11   #15
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Not sure if one can actually "switch off" the WAAS on the garmin 182c. In which case if I am "receiving" WAAS it is more inaccurate than not!?!
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Old 11 May 2004, 09:01   #16
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WAAS Accuracy

My understanding is that with WAAS just putting out a carrier signal, it just means that the GPS thinks (or indicates) that it is more accurate, but is in fact no more accurate than if you had WAAS switched off. I don't see why it should be any less accurate than a standard (non WAAS) system.

Incidentally, I don't know this for a fact - but someone did try to explain it to me the other day - and it sounded reasonable.

Dylan...
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Old 12 May 2004, 08:37   #17
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Hi folks

Well their I cant find out any actual dates but have the following !.

Initial tests of EGNOS was using a specially-equipped Inmarsat satellite.
Cant find out if this is what we are seeing or its the actual satalites.
I suspect the actual satalites by now.

The first test signal was on Friday 6 June 2003 and we should have a full system working very soon. The system was supposed to go live Spring 2004 with the operational readiness review in April 2004 . Assuming it conforms it should go live very soon after

If I get any actual go live dates I will post them.

Regards Gary
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Old 17 May 2004, 17:45   #18
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Out this evening and still struggling to get a WAAS signal - test or not
I have cut and rejoined the antennae cable and hoping this is not responsible. Getting good reception of satellites otherwise.
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Old 18 May 2004, 13:34   #19
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Hmmmm. Not sure whether this is right or not, but have just been having a play with my GPS in the garden (GPSMap 76).

If I turn on WAAS enabled I suddenly get two new satelites appear in the sky (Nos. 33 & 44). Would I be right in saying these might be the Egnos sats? They dissapear again if I disable WAAS. Doesn't make the blindest bit of difference to the accuracy mind you. Didn't manage to lock onto them though!

Also, a few times last year I remember the sat strength bar showed a little 'D' symbol at the bottom and the display showed '3D Differential'. Might this have been the WAAS/Egnos actually working. I think accuracy went down to less 10' at the time.
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Old 18 May 2004, 15:30   #20
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EGNOS test signal comes on june 2004 they are now going to link it to Gallileo
test signal 2005 operational 2008
WAAS is for the benifit of the federal aviation authority so planes can fly/land
better knock on effect is maritime benifits for greater accuracy ie down to 3 metres but only if you are in America see www.rin.org.uk great site and info
on their for the tech heads
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