Waas Of Questionable Value?

[+Thot]

The gist of this thread in the Getting Started forum is that WAAS is of marginal value, and results are sometimes worse with it than without it. Is there general agreement on this? I can imagine there are unusual circumstances where it does more harm than good, but I wouldn’t have guessed this happened often enough to mention it to a newbie who’s trying to figure out whether he should have it on or off. I thought in most circumstances where you can receive the signal it will give better answers with it that without it.

 

Certainly my EPE numbers are usually lower after it acquires the WAAS signal.

Edited December 15, 2004 by Thot

[+Renegade Knight]

My experience with WAAS was this.

 

Turn it on, EPE gets worse. Yuck. Turn if off.

Turn it on, EPE gets worse. Yuck. Turn it off.

Turn it on, EPE gets worse, forget about it and go caching. Later I notice WAAS is on and my EPE is single digit. Cool.

 

It takes a long time to build the WAAS tables or whatever your GPS needs to do ti effectivly use WAAS. Once I had a good WAAS lock I've never seen worse EPE than without it. However I did notice the delay in updates while trying to find ground zero.

[+Blaidd-Drwg]

Using a Vista, I've just left the WAAS turned off. I don't believe that the benifit is worth any extra time. To date, I haven't noticed that I'm off by a large amount consistantly from the locations posted on the cache pages. IMO given any GPSr, even my little yellow etrex, I can get close enough to figure the hiding location.

[+Timpat]

I have WAAS enabled when using both my Garmin Legend and Map60C. I use them a lot with my work in surveying and GIS mapping, and find that WAAS will consistently provide better estimated accuracy. Typically I will see an EPE of about 4 to 6 meters without WAAS, and about 2 meters with WAAS enabled. This depends of course on your location, and a clear view of SV-35. For general caching a difference of a couple meters doesn't really enter in to this debate. I've seen my EPE as low as 1.8 meters on a regular basis when in open areas.

[+Gonzo-YT]

My take on WAAS, which I have expounded at great length in these forums:

 

1. Sub-meter accuracy is uneccessary for geocaching, or for any type of wilderness navigation. You need to get within 10m and then do a ground search, and almost any receiver will get you that. So, the rest of this post is basically just academic.

 

2. Geometry is everything. The position of the satellites in the sky is the most important determining factor in accuracy. Period.

 

3. I have used a GPS 72 that was getting WAAS signals and a Vista C that wasn't, one in each hand, and there was no significant difference. Even if there was, it wouldn't make a difference (see #1).

 

Regards,

Anthony

[+jollybgood]

I leave WAAS on all the time. I get a good lock locally and I like seeing single digit accuracy on the screen. I haven't noticed any problems using it. It's there -- so I use it.

 

I do agree with one of the other posters. The key is using it and allowing your unit to gather data.

The first time I turned on WAAS it took 30 minutes before it was able to get a full lock.

 

Now it does so about as fast as I do when WAAS is turned off.

 

Of course WAAS is only useful for caching if the owner of the cache had WAAS turned on when he hid his cache. If a hider's accuracy is only 18 feet having WAAS turned on isn't going to do much good.

[AJK]

With tree cover in New England, WAAS is near impossible to maintain (for me). Out west, without trees, WAAS works, but without it I usually find the cache quickly and within feet of ground zero. On the road in New England I can get it, but I don't need that sort of accuracy for navigation.

 

My perception is that it takes longer for my compass to catch up with direction with it on, but that may not be true, or may only be true when the WAAS signal is poor.

 

For me, little use. For cache placement, I'd rather rely on checking on an ortho.

[vr12]

How turning WAAS OFF is helping in anything ?

I keep in ON.

[+IVxIV]

How turning WAAS OFF is helping in anything ?

I keep in ON.

Turning it off makes the batteries last longer, at least in my iFinder Pro it does. Well, that's something

 

My previous Magellan GPS 315 had no WAAS, which didn't seem to be much of a handicap at the time. But after getting the WAAS equipped iFinder Pro I was able to locate 2 caches that had previously eluded me.

[2oldfarts (the rockhounders)]

With 2 Magellan Platinums with WAAS on I can go to a benchmark that has Adjusted Coordinates and zero out with-in 3 feet of that benchmark. And they will do it consistantly.

 

It works for us.

 

John

[robertlipe]

The recurring trend in bad WAAS experiences including battery life, display speed, impaired EPE values, and such seems to be "Garmin". Notice how Magellan users just don't see that behaviour.

 

That said, I tend to agree with Gonzo-YT's take on it.

[Alphawolf]

Watch how it slows down your processor speed while turned on! Maps won't re-draw nearly as fast. WAAS sells GPS receivers for the big makers, but does little else for most of us.

[vr12]

The recurring trend in bad WAAS experiences including battery life, display speed, impaired EPE values, and such seems to be "Garmin".  Notice how Magellan users just don't see that behaviour.

 

That said, I tend to agree with Gonzo-YT's take on it.

I have not noticed any change in display speed (60CS and Vista )

The battery life ? it is 12 channels reciever all the time and when you turn

WAAS on/off it just redistribute channels among sattelites.

Edited December 18, 2004 by vr12

[+NightPilot]

I don't think you're going to see a lot of difference in actual accuracy, under real conditions, with WAAS on or off. The estimated error shown, which is an implementation of the manufacturer, can't really be relied on. WAAS is an FAA intitiative, designed specifically to improve reliability of vertical guidance for aircraft flying instrument approaches. The horizontal accuracy was already more than good enough, and needed no improvement. We've been flying instrument approaches using GPS since long before SA was turned off, and any improvement in horizontal accuracy with WAAS will only be incremental, and likely too small to be measured in the real world, displayed EPE notwithstanding. WAAS signals aren't likely to be received at all in the woods; they're designed for use in the air. If you see reduced battery life and slower display updates, you're probably better off with it turned off. If you want to leave it on and think it helps you find caches, then leave it on. It's not a life or death decision down here. In the air, I still haven't seen an IFR-certified GPS with WAAS capability. They're supposed to be coming real soon now, but with aviation GPS units costing several thousand dollars, and the benefits being comparatively small, I don't expect to see one before I retire.

Edited December 18, 2004 by NightPilot

[+EWDaron10]

If you look at the Satellite screen in your GPSr, you will most likely see that the WAAS satellites are very close to the horizon. At least that's what I see here in Southern Oregon. With that being the case, if you are in a valley or someplace else where the view of the sky near the horizon is blocked, WAAS won't make any difference. As a result, I have been keeping it turned off and have not had any problems while navigating.

[+KJ&MShelly]

WAAS greatly improves accuracy if there are atmosphere disturbances(solar flares).

 

WAAS

[+jollybgood]

The recurring trend in bad WAAS experiences including battery life, display speed, impaired EPE values, and such seems to be "Garmin".  Notice how Magellan users just don't see that behaviour.

 

That said, I tend to agree with Gonzo-YT's take on it.

I have not noticed any change in display speed (60CS and Vista )

The battery life ? it is 12 channels reciever all the time and when you turn

WAAS on/off it just redistribute channels among sattelites.

I agree one hundred percent. I see zero difference in processor speed/redraw rates with WAAS turned on/off. Battery life is just fine on my 60cs.

 

maybe this is a problem with older Garmins like the GPSV. But certainly not on the 60CS. At least not from what I can tell. If there is it's neglible enough that I'm not going to spend much time worrying about it.

 

Again, I like seeing 5 ft. accuracy showing on my Unit when I'm driving down the highway. It doesn't mean a whole lot. It's just a nice thing to see. Obviously when I head off into the bush I'm not going to be pulling WAAS for the most part. But since I see zero difference with WAAS turned on or off as far as performance I see no reason to turn it off.

 

For there's simply no reason not to use it on the 60CS.

 

I have noticed there seems to be a lot urban myth surrounding WAAS.

 

When I first got my GPSr I recall reading "Dont' turn it on. You won't be able to get a reliable lock anyway." I manage to get a lock on WAAS nearly 95% of the time as it turns out.

 

I read it will suck your batteries dry. I use rechargeables (yawn). No big deal even if it DID drain batteries faster. As it is I find I'm changing batteries far less often than I did with my GPSV.

 

As for performance slow down. Maybe. Maybe not. Again I think it all depends on the processor in your unit. Maybe on the GPSV -- which I found to be slow any way when calculating routes and doing screen redraws. But I don't see this with my newer unit.

 

So perhaps a lot of this anti-WAAS sentiment is based on older technology/units. The difference between GPSrs made just a few years ago and today are night and day as far as speed and so forth.

 

I should point out I rarely use my electronic compass. Just really haven't had a need for it. So maybe WAAS slows down the compass. I really don't know or really care for obvious reasons.

 

Anyway, something to keep in mind when you read the comments here. Your mileage may vary depending on your GPSr.

Edited December 19, 2004 by jollybgood

[robertlipe]

Yes, I should have been clearer. The stuff you read about WAAS sucking the soul from your unit tends to come from units of the pre-C era Garmins. The 2004-ish Garmins seem to be as immune from these bad side effects as the Magellans have been since they added WAAS several years ago.

 

Signed,

Trying To Keep Folkore To A Minimum.