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WAAS?


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I have a Magellan Meridian, do most of my caching in Florida, and use WAAS all the time. I find it gives me significantly better EPE numbers, once the unit has been on long enough for the corrections to be available.

I have seen a situation where I was doing a cache in a deep valley in Maryland where reception of the WAAS sattelite was coming in and out because of very poor geometry, and this *may* have been the reason my fix was hopping around a little. I'm not sure what the software in the GPSR does in that circumstance...i.e. does it cache the WAAS corrections even if the fix on the WAAS bird blinks out for a while?

At any rate, in my normal circumstances it's useful and YMMV. icon_smile.gif

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I have a Magellan Meridian, do most of my caching in Florida, and use WAAS all the time. I find it gives me significantly better EPE numbers, once the unit has been on long enough for the corrections to be available.

I have seen a situation where I was doing a cache in a deep valley in Maryland where reception of the WAAS sattelite was coming in and out because of very poor geometry, and this *may* have been the reason my fix was hopping around a little. I'm not sure what the software in the GPSR does in that circumstance...i.e. does it cache the WAAS corrections even if the fix on the WAAS bird blinks out for a while?

At any rate, in my normal circumstances it's useful and YMMV. icon_smile.gif

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quote:
Originally posted by infosponge:

does it cache the WAAS corrections even if the fix on the WAAS bird blinks out for a while?


Yes. The WAAS corrections are good for several minutes (I vaguely remember the number six coming up a long time back), and IIRC, the unit should at least keep using them for two minutes or so (again, according to my vague memories from back when none of our receivers had WAAS).

 

As for WAAS helping, it hasn't hurt me down in Louisiana, and it appears to help.

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quote:
Originally posted by rickrob:

Do you like WAAS or not? I have not used it. Please tell me if it works

Thanks


 

It all depends on where you are and how clear the unit's view is to the horizon. WAAS has not really helped in my case, in fact it decreases my accuracy and has been consistent in this respect on all my WAAS units (GPS V, eTrex Vista, GPSMAP 76S, MAP 330, Meridian Gold). I have also found that screen redraws with WAAS enabled are slower. I'm in the Los Angeles area (Whittier) and about the only time I've seen WAAS do any good was down at the beach. I expect it would work very well on the water in a boat which is geared more towards WAAS's intended purpose. Since LA is mountainous/hilly, I simply disable it and don't really think about it.

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As a matter of fact I was playing around with WAAS today while looking for a cache. (Didn't find it, wimped out...too hot). Anyway, in the parking area, I was walking around seeing how low my accuracy would show with and without WAAS. I found that It would go as low as 13ft without WAAS and it went down to 12ft once with WAAS. The rest of the time it was about 15-18ft without and it varied from 15-30ft with. I have a Garmin V and it shows the position of the sats overhead. When I am picking up the satellites lowest on the horizen is when I get the best accuracy. If WAAS doesn't have a very clear view of the sky, the accuracy jumps up and down alot. I usually keep WAAS off most of the time. That's just my observations icon_smile.gif

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As a matter of fact I was playing around with WAAS today while looking for a cache. (Didn't find it, wimped out...too hot). Anyway, in the parking area, I was walking around seeing how low my accuracy would show with and without WAAS. I found that It would go as low as 13ft without WAAS and it went down to 12ft once with WAAS. The rest of the time it was about 15-18ft without and it varied from 15-30ft with. I have a Garmin V and it shows the position of the sats overhead. When I am picking up the satellites lowest on the horizen is when I get the best accuracy. If WAAS doesn't have a very clear view of the sky, the accuracy jumps up and down alot. I usually keep WAAS off most of the time. That's just my observations icon_smile.gif

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EPE is not a real test of accuracy/precision. I have not noticed any diffrence with WAAS, I know my unit is more stable then me 315 use to be, but I belive this is more the firmwares doing than WAAS.

 

Wyatt W.

 

The probability of someone watching you is directly proportional to the stupidity of your actions.

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The first thing to verify with WAAS is your ability to receive it. Garmin GPS receivers will show you on the satalite page by showing a D in the satalite column if that satalite is having WAAS correction applied. Not sure on the others.

 

I used to have WAAS turned on in the plane gps to see if it worked. Above the hills at >2500 feet I receive pretty good WAAS signal. On the ground I've only seen it once or twice, but I had a great view of the sky. When you're at 5,000 feet doing 180mph who cares if your EPE is 4 feet? If the update interval is 1 second, I'm 260 feet away the next second. =) Does help on altitude though.

 

WAAS is intended as an aviation aid, and in handheld gps receiver it's just a marking gimmic, IMNHO. Probably fairly easy to add, just a little programming.

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Simply being able to receive a WAAS signal doesn't mean all that much unless one is actually within the ground station network proper.

 

As the old saying goes, only in America, only in America and then with problems especially for applications for which is was never designed or intended.

 

Recreational type handhelds really don't and probably won't have the refinements in the software to make use of the what the system is really all about even if they can adequately recieve a signal from the present inadequate geo satellite configuration.

 

Cheers, Kerry.

 

I never get lost icon_smile.gif everybody keeps telling me where to go icon_wink.gif

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Simply being able to receive a WAAS signal doesn't mean all that much unless one is actually within the ground station network proper.

 

As the old saying goes, only in America, only in America and then with problems especially for applications for which is was never designed or intended.

 

Recreational type handhelds really don't and probably won't have the refinements in the software to make use of the what the system is really all about even if they can adequately recieve a signal from the present inadequate geo satellite configuration.

 

Cheers, Kerry.

 

I never get lost icon_smile.gif everybody keeps telling me where to go icon_wink.gif

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