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i3 WAAS or GPS norm.
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matb
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PostPosted: Fri Apr 07, 2006 11:54 am    Post subject: Reply with quote

"In either scenario, it only really understands that I've deviated from the route (in either normal GPS mode, or EGNOS) when I'm either just on, or just over the roundabout".




lester

in normal mode i felt that the system thought i was still on the main carriageway although i had travelled along the exit for some 200yds.
it then recalculated sending me still along the main section, turning at the next junction and basically doing a u turn.
when i looked at the map on screen it showed the corrected route and the proper route.
once on the proper route, by ignoring the recalculation, and turned off the roundabout it then reverted back to the correct route.

in waas/egnos it seemed to know that i had taken the exit, as requested, at the same time as the normal thought i had not. hence no recalculation and a straight run down to the roundabout.
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Lester_Burnham
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PostPosted: Fri Apr 07, 2006 12:19 pm    Post subject: Reply with quote

matb wrote:
lester

in normal mode i felt that the system thought i was still on the main carriageway although i had travelled along the exit for some 200yds.
it then recalculated sending me still along the main section, turning at the next junction and basically doing a u turn.
when i looked at the map on screen it showed the corrected route and the proper route.
once on the proper route, by ignoring the recalculation, and turned off the roundabout it then reverted back to the correct route.

in waas/egnos it seemed to know that i had taken the exit, as requested, at the same time as the normal thought i had not. hence no recalculation and a straight run down to the roundabout.


Oh I get that - when you use EGNOS it correctly detected you had either deviated by using the slip road, or vice versa, remained on the motorway.

I only really pointed out my findings by saying a similar motorway and slip road arrangement, that neither normal nor EGNOS detected my deviation(s) from the route(s) - I'm guessing - because the roads / lanes were fairly close, and because within a certain proximity it snapped me to the planned route.

And that's what I don't get for motorway slip roads and any assumed improvement from EGNOS accuracy - within a certain tolerance and it snaps you to the road, and hence the route - in my scenario, EGNOS didn't make a difference to that.

I could understand a difference in fore and aft directions, but slight variations left and right it seems to assume you're on the road.

It's the same for me with EGNOS turned on, in a supermarket car park, that's fairly close to the road - once I get within a certain distance, it assumes I'm on the road.
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Aitch2
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PostPosted: Fri Apr 07, 2006 12:30 pm    Post subject: Reply with quote

That's the problem, Lester - you're driving on the wrong roads! :D

Aitch
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Lester_Burnham
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PostPosted: Fri Apr 07, 2006 12:48 pm    Post subject: Reply with quote

Aitch2 wrote:
That's the problem, Lester - you're driving on the wrong roads! :D

Aitch


No, no, no... I'm driving on all the right roads, just in the wrong order ;-)

($ to Eric Morecombe)
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matb
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PostPosted: Fri Apr 07, 2006 2:44 pm    Post subject: Reply with quote

so i think it is safe to say then, that in my case, the waas/egnos detected correctly a lateral movement of less than 30ft.

i dont want to deviate from the main subject but could beta 2.82 that i am also running be a contributory factor to this particular incident of accuracy.
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Lester_Burnham
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PostPosted: Fri Apr 07, 2006 3:11 pm    Post subject: Reply with quote

matb wrote:
so i think it is safe to say then, that in my case, the waas/egnos detected correctly a lateral movement of less than 30ft.

i dont want to deviate from the main subject but could beta 2.82 that i am also running be a contributory factor to this particular incident of accuracy.


No different from me, then - I flashed to 2.82 on the day it came out.

That's the one thing I don't experience, personally - the lateral position accuracy, mine always assumes I haven't deviated - in either EGNOS or normal, unless it's REALLY obvious I'm on a different road.

The slip road I've personally tested on, gradually drops down, and laterally moves away from the main carriageway. There's traffic lights at the end, which leads onto a big roundabout. It takes actually driving on to the rounadbout and a change in vector to get it to recalculate in either EGNOS or normal GPS reception. And the same if I continue on the main route - it seems to take actually crossing where it would think I should be on the rounadabout, before it detects and recalculates.

That's the funny thing, for me - this was one of the things I checked, to see whether EGNOS would be of any value to my use.
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matb
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PostPosted: Fri Apr 07, 2006 3:34 pm    Post subject: Reply with quote

lester

are you running on v8 maps, plugged into the car with batteries installed aswell, if so then we still have no answer, as we will both be running the same.
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Lester_Burnham
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PostPosted: Fri Apr 07, 2006 3:38 pm    Post subject: Reply with quote

matb wrote:
lester

are you running on v8 maps, plugged into the car with batteries installed aswell, if so then we still have no answer, as we will both be running the same.


Yup - V8 maps, most of the time on ciggy power. Occasionally (and it is occasionally) I do use battery power. Batteries are always installed, though.
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oddsock
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PostPosted: Fri Apr 07, 2006 4:22 pm    Post subject: Reply with quote

Is there anything on the i3 that tells you that you are actually obtaining differetial correction when in navigation mode .The reason I ask it that yesterday I covered 200 miles around the Pontipridd /Cardiff area with 2 Garmin units running,both were on Waas, one was in nav mode and the other in Gps mode to For around half of the time there was no lock on sat 33 so i wonder just how practical it is to bother using it . Btw wife was driving Smile

Dave
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BAVC10
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PostPosted: Fri Apr 07, 2006 4:24 pm    Post subject: Reply with quote

I've e-mailed Garmin Tech Support to ask which one they recommend for the UK. Might be worth you a few of us trying to see if we get a consistent and definitive answer.
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Lester_Burnham
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PostPosted: Fri Apr 07, 2006 4:32 pm    Post subject: Reply with quote

BAVC10 wrote:
I've e-mailed Garmin Tech Support to ask which one they recommend for the UK. Might be worth you a few of us trying to see if we get a consistent and definitive answer.


I suspect it may well be an individual thing - whichever mode works best for people that suites their needs, and exhibits least issues that affect them.

Same with many of the other configurable options.
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matb
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PostPosted: Fri Apr 07, 2006 5:08 pm    Post subject: Reply with quote

lester

i have just downloaded 2.9

lets see what happens now then.
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PaulB2005
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PostPosted: Fri Apr 07, 2006 9:29 pm    Post subject: Reply with quote

Been using Normal since Xmas. Tried WAAS/EGNOS today on a route that i know works ok in Normal mode. On 3 occassions the Sat Nav continued down a road i had turned off and then had a mini-fit.

Switched back to Normal, same route, no problems.

At each junction i have a good clear signal.
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Lester_Burnham
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PostPosted: Sat Apr 08, 2006 2:35 pm    Post subject: Reply with quote

PaulB2005 wrote:
Been using Normal since Xmas. Tried WAAS/EGNOS today on a route that i know works ok in Normal mode. On 3 occassions the Sat Nav continued down a road i had turned off and then had a mini-fit.

Switched back to Normal, same route, no problems.

At each junction i have a good clear signal.


Indeed - much the same experience as me - I've never noted or suffered from any comparative lack in accuracy in normal mode, compared with EGNOS.

But I HAVE experienced quite odd behaviour in routing that went away when recalculating on normal.
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sunstrip_steve
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PostPosted: Sat Apr 08, 2006 7:45 pm    Post subject: Reply with quote

Running 2.70 and v8 i3 the EGNOS mode seemed to offer slightly better detection of lateral deviation. There are a number of slip roads where in normal mode it will not detect that i have turned off (especially if this is not the suggested route), but EGNOS mode does.
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