If you have WAAS do you use it while geocaching?

24.7k · May 14, 2003

Thought I'd throw this out and see how the numbers turn out.

So if you have a WAAS enabled GPS do you use WAAS or do you keep it off?

Feel free to post flames, or why you keep it on, or off.

=====================

Wherever you go there you are.

May 14, 2003

Nope. I tired it early on, but it doesn't seem to work very well among the mountains and canyons we usually cache in.

Ron/yumitori

May 14, 2003

while geocaching, yes. I'm not worried about battery drain. 90% of the time my GPS is connected to my cigarette lighter.

I haven't yet used my WAAS enabled GPS for backpacking....if the drain is serious I probably would not use it unless it was a short trip. - JamesJM

4.7k · May 14, 2003

there isn't a choice for sometimes.

sometimes i use it. other times it seems to slow me down.

it doesn't matter if you get to camp at one or at six. dinner is still at six.

May 14, 2003

I do mess around with it from time to time, but haven't found it to be any more accurate anyway.

I'm in Colorado, don't know if that makes a difference.

When you see the light at the end of the tunnel, make sure it's not a train coming at you

May 14, 2003

I read in another forum that WAAS is good to use when placing caches but not so good when finding caches because it makes most GPSRs update slower.

May 14, 2003

I generally don't use it when finding. I don't know how accurate the owner's coordinates are, so it may just mess me up even more.

When hiding though, particularly when I have a clear view of the sky (and especially when I'm at or near the coast), I'll use it. I don't know if its helped anyone in finding a cache of mine, but I figure that it couldn't hurt.

----

When in doubt, poke it with a stick.

May 14, 2003

I've yet to find it helpful in finding a cache.

Frankly, I don't have any application for it at all, other than a curiosity. Who really needs WAAS while hiking?

George

24.7k · May 14, 2003

To clarify, I mean use WAAS normally or don't use it normally. I think we all fiddle with it.

What's interesting is that so far (20 votes) the majority of posters say they don't use it, but the majority of voters say they do.

=====================

Wherever you go there you are.

May 14, 2003

quote:
Originally posted by Renegade Knight:
What's interesting is that so far (20 votes) the majority of posters say they don't use it, but the majority of voters say they do.

Do you think it has anything to do with the way the question was phrased and the limited number of choices? For example, if someone uses WAAS only infrequently or only for placing caches, the correct choice would be "Yes I use WAAS".

Even if they only use WAAS 1% of the time.

May 14, 2003

this is neither here nor there, but....

i'm not sure if my meridian gps has an option to not use WAAS. it just lets me know if WAAS is available or not on the status screen.

so, if it says it's available -- i use it ;P

1.3k · May 14, 2003

Always on. The other day with WAAS enabled, my vista displayed an EPE of 6 feet for about fifteen minutes. I was tracking twelve sats (including the WASS). It would be hard to determine if it really makes a big difference because I almost allways enable it unless I can't lock onto the WAAS sat. (35) available in my area. Typically I get under 25 foot accuracy at any given time.

"Searching with my good eye closed"

May 14, 2003

I don't use it. The one time I tested it out (high on a peak with a very strong signal) the reported accuracy was consistantly worse in both receivers I was using (Legend and Vista) that without WAAS.

It later occured to me that WAAS was meant for aviation so maybe the altitude was adjusted for accuracy. Not having thought of that when I was trying it out I didn't check the altitude accuracy.

May 14, 2003

I turned it on when I got my Venture, and haven't turned it off since.

I do use it backpacking. I haven't found it a problem to carry two or four extra batteries--actually I usually carry 8, since my camera takes two AAs and so does the back-up battery case for my 2-meter radio.

The slower updates aren't a problem for me either, since I walk kind of slowly...

Actually, once I get to within 20 to 25 feetof a cache I tend to put the GPSr in my pocket and just look.

Dave_W6DPS

My two cents worth, refunds available on request. (US funds only)

May 14, 2003

An interesting and possibly related topic.

About Raytheon testing the WAAS system for FCC certification, including time it will be unavailable or degraded....

Dave_W6DPS

My two cents worth, refunds available on request. (US funds only)

9.5k · May 14, 2003

My GPS is on default mode with WAAS enabled. I haven't messed with the hidden menus since I received it. Does it help or hurt? Well, I can tell you with the stats I've kept, I'm on top of caches with the given coordinates at least 75% of the time. That includes two waypoints in a multicache hunt today. My finds are few compared to most of you, but I'm thinking I won't be turning off the WAAS.

Cheers!

TL

May 14, 2003

Odd how you can do that when most caches haven't been placed with WAAS. And even so, you could still expect to be off by more than several feet with the error margin between two GPS receivers (the hider and the placer).

Sure wish I could get one of these *magic* GPS units that always (or almost always) seem to put people right on top of the cache.

George

2.7k · May 14, 2003

I bought an etrex Vista a couple weeks ago and have left the WAAS on. It seems to perform pretty well for me so far. Battery drain is definitely a bigger factor in the Vista than my old Summit, but the Vista's pluses out weight that minus. I haven't kept any stats, but I've been right on top of more than a few caches.

1.3k · May 14, 2003

I'll sell you mine for $500.

Seriously, though. I was within three feet of two recent caches when my unit read 0ft. I have no idea what the hider used, or if he was way off, and the sats put me way off and chance placed me right there. Both caches were placed by the same guy, very close to one another and on the same day. I found them within 15 min. of each other, so that suggest to me that the sat geometry for hiding both was similar, and likewise for finding both. Incidentally, the three foot error I observed was roughly in the same direction on both caches.

"Searching with my good eye closed"

38.2k · May 14, 2003

I've yet to see a difference in accuracy between having WAAS on and off. I've played around with it in the field and have yet to see a benefit.

"It has been my experience that folks who have no vices have very few virtues" -Abraham Lincoln

May 14, 2003

I second BrianSnat. I haven't seen a difference between readings with and without WAAS.

I do turn it on when placing my caches, then I take about 10 waypoints over about 10 minutes, and average by hand (my poor GPSr doesn't average...). But for searching, I don't use WAAS.

Adversity is certain, misery is optional.

24.7k · May 14, 2003

Looks like most geocachers who have WAAS use it.

In my case I don't. It causes a noticible lag on my GPS V and the lag bugs me more than any increase in accuracey would benifit me.

A friend with a Vista has had his GPS say 3' of reported accuracy while using WAAS. So given long enough it does work.

My experiments (and all are short term) showed a degridation in my accuracy but I'm willing to bet that given longer my GPS would settle in to greater accuracy.

Thanks everyone.

Leatherman, you nailed this one.

=====================

Wherever you go there you are.

9.5k · May 14, 2003

quote:
Originally posted by nincehelser:
Odd how you can do that when most caches haven't been placed with WAAS. And even so, you could still expect to be off by more than several feet with the error margin between two GPS receivers (the hider and the placer).

Sure wish I could get one of these *magic* GPS units that always (or almost always) seem to put people right on top of the cache.

George

Not really, George. I try to go out when my GPS will average 30 feet EPE or less. That's merely a parameter I set for myself. My log data (albeit short) points towards this as the most likely time when most caches are hidden and averaged. Some hiders are better at getting a lower EPE for their coordinates, some aren't.

When I have a difference of a few feet from ground zero, I make note of this... as noted by my 75% accuracy. Instead of sniping, perhaps you should get to know your receiver a little bit better. These caches and benchmarks are perfect opportunities to do just that.

Again, does WAAS affect this? I don't know. I'm not being hurt by it and I have rechargeable batteries to handle the miniscule drain. If I didn't want WAAS capability, I wouldn't have bought it.

Cheers!

TL

May 15, 2003

quote:
If I didn't want WAAS capability, I wouldn't have bought it.

You have less and less choice on that every day as new units come out. It's a selling point and manufactures know it. Forget wether or not it improves anything. It's moot.

1.6k · May 15, 2003

Must be a conspiracy. Develop a bogus technology and push onto the market for... what? More money?

Two things, I know I've done a little experimenting with a STMap, marked the end of my couch, and I could watch my "position" drift slowly around me within a 10-15' area--often much less--day after day.

Second, I'm no expert, but I don't think WAAS slows anything down as it only updates every so often as the conditions that effect accuracy change slowly. Somebody can fill us in on the update, but it's like once a minute or every five minutes. Whatever it is, the bottom line is, it shouldn't be effecting the update performance on-site.

If you're using a Magellan, the lag is probably from the circuitry that averages out it's own readings. This is different from the automatic averaging when you are sitting still. Because of this averaging the "pointer dance" some have reported near the waypoint is foreign to me.

I know my unit gets a repeatability of a point or two in the field.

Oh, and another thing, does turning off WAAS save batteries? If I understand correctly WAAS uses two of the twelve receivers in your unit. If those receivers are always on, they'll still have a power drain. Is the ciruitry used to process the WAAS signal that much of a power hog? I wouldn't think so.

As far as I know, the only reason to turn off WAAS is because you simply can't get the signal and you want those two receivers in case you can actually get 12 positioning sats.

Overall, being in the southeast and having a strong WAAS signal, I'll keep it on as my batteries generally last all weekend.

CR

May 15, 2003

I use it.. i use my GPS in the truck all the time.. i notice when I have a good WAAS signal and a least 5 satellites it is extrmely close to the mark (puts me right on the road on my display) when WAAS isnt available I am almost always off the road by as much as 50 feet, even if I have 8 satellites... of course I am on the east coast so the satellite is easy to hit.

2.3k · May 15, 2003

I agree with TotemLake, I don't mess with the hidden menus for toggling WAAS on and off with my MeriPlat, so WAAS is always on and I always get 7-10' EPE readings while caching. Doesn't get much better than that.

May 15, 2003

quote:
Originally posted by Dave_W6DPS:
I turned it on when I got my Venture, and haven't turned it off since.

The slower updates aren't a problem for me either, since I walk kind of slowly...

Actually, once I get to within 20 to 25 feetof a cache I tend to put the GPSr in my pocket and just look.

Dave_W6DPS

My two cents worth, refunds available on request. (US funds only)

Ditto, even down to the Venture! I turned it on when I first got the device and didn't understand the technology enough to know whether that was good or not. I've left it on ever since.

UPSCWRU (University of Puget Sound, Case Western Reserve University)

9.5k · May 15, 2003

True regarding fewer choices of GPSr's without WAAS, but when I did buy the MeriPlat, the choice of features to no features was still a wide range. When I made the purchase, I followed my PC philosophy upon my purchase... buy as much as I can now so there will be fewer regrets later.

I never said the MeriPlat doesn't drift. It does. That's going to be a given with satellite orbit and loss and gain of satellite acquistion dependent upon xy position.

My understanding (and it is a layman's understanding) of the real gain in WAAS is that the station, be it a DGPS ground station or a WAAS satellite, is that their positions are fixed, the satellite being geosynchronous. This improves the accuracy because of the known fixed location and the almanac really doesn't change that much. Currently, the closer you are to the coast with fewer obstructions to mask the horizon, the better your odds are of receiving accurate readings of WAAS. I understand there will be more launched to give more coverage over the Northern Americas continent. Would this not help to reduce the bumble bee dance?

Cheers!

TL

May 15, 2003

quote:
Originally posted by TotemLake:
When I have a difference of a few feet from ground zero, I make note of this... as noted by my 75% accuracy. Instead of sniping, perhaps you should get to know your receiver a little bit better. These caches and benchmarks are perfect opportunities to do just that.

Perhaps you should geocache a bit more. A sample of 9 caches isn't statistically significant. Perhaps you really out to do quite a few more more and then analyze your data before throwing out "statistics".

If you're consistantly "on top" of the coordinates at the cache 75% of the time, you should try your luck in Vegas!

George

[This message was edited by nincehelser on May 15, 2003 at 09:19 AM.]

May 15, 2003

Mine stays on, because I'm to lazy to turn it off and I really dont see a problem with batteries.

May 15, 2003

quote:
Originally posted by Sissy-n-CR:
Must be a conspiracy. Develop a bogus technology and push onto the market for... what? More money?

Well, I think there might be a few in the aviation industry who might agree with that statement.

As for manufucturers of consumer GPS recievers, it really isn't that big of a deal to add the ability, so they do it, and it's another mark on the feature list.

So far I haven't been real impressed with WAAS, but that may change once the system is fully operational and stabilized. The last I heard that wasn't going to be until December.

George

9.5k · May 15, 2003

quote:
Originally posted by nincehelser:

quote:
Originally posted by TotemLake:
When I have a difference of a few feet from ground zero, I make note of this... as noted by my 75% accuracy. Instead of sniping, perhaps you should get to know your receiver a little bit better. These caches and benchmarks are perfect opportunities to do just that.

Perhaps you should geocache a bit more. A sample of 9 caches isn't statistically significant. Perhaps you really out to do quite a few more more and then analyze you're data before throwing out "statistics".

If you're consistantly "on top" of the coordinates at the cache 75% of the time, you should try your luck in Vegas!

George

There you go sniping again. I consistantly said it was a small list. Stats have to start someplace. That's not to say my data is any less valid... which you seem to be implying. In fact, IF anything, I did expected less than 50% accuracy even at this early stage because of all of the variances that are in play. Wouldn't you agree with that expectation? I intend to keep log and will advise if it changes.

Nor do I have the time on my hands that some of you have to go out and look for caches. And no; I won't put my money against a house that is designed to cause you to lose. I'm not that foolish.

I'm curious though, with your number of finds, have kept track of your groundzero finds?

Cheers!

TL

8.9k · May 15, 2003

Last June (2002), we had a little "fun" with our second annual Chicago event. The locals to the spot found a marker at the picnic grove and gave that as the coordinates for the event. When everyone arrived, we had people use "Julie" flags to mark where their GPS zeroed out.

There were a couple cachers that had WAAS enabled GPS devices that were 10-15 meters off when it was off. They said they never used their WAAS. They turned their WAAS on and were right on top of the marker (the marker was marked with WAAS on). They swore they would never leave WAAS off again.

With that in mind, I think if you are Hiding you are under an obligation to obtain the most accurate coordinates possible. The seekers can determine if they want to use WAAS or not. Now the debate can start as to whether or not enabling the WAAS actually gives you more accurate coordinates.

Kerry? I'd be interested in your take on this.

Markwell

Chicago Geocaching

May 15, 2003

Wow, it seems that some are emotional about their WAAS. I played with it quite a bit when comparing my sportrak and Legend. In clear conditions with great reception, it seemed to help once the units had been on with WAAS reception for at least 20 minutes. <20 minutes it seemed to sometimes make the error greater. In the woods and canyons I really couldn't tell, as other error factors are so big it's hard to tell what little things like WAAS are doing. In most of the more scenic and fun places to hike around here, WAAS isn't really an issue as you can't see the WAAS birds at all, so for me it's not an issue either way.

As for the seetings I use, I leave it on, as it does appear to have a slight positive effect on accuracy, and I didn't really see it as a negative. In buying a new receiver however, it's fairly low on the list of factors I look for.

2.3k · May 15, 2003

For general use, I leave the WAAS off on my Legend. I leave it off because I often cannot receive the 2 WAAS birds, and it seems to tax the processor, causing the unit to slow. When I placed my 2 caches, I used WAAS, and took marks over several days to get the best waypoints possible.

When standing over the super-accurate adjusted benchmarks, having WAAS on improves the position by several feet.

I also have a Meridian and there is no menu item to turn off WAAS.

May 15, 2003

quote:
Originally posted by TotemLake:
There you go sniping again. I consistantly said it was a small list. Stats have to start someplace. That's not to say my data is any less valid... which you seem to be implying.

Not sniping. Just pointing out the reality of statistics. If your sample size is too small, it is very often not representative of the whole. I think you'll find that as you continue geocaching, your 75% is going to decrease dramatically.

All other things being equal, the validity of a data set increases as the number of samples increases. It's all a matter of statistcal signficance.

How many times have I zeroed out? Not often. Sometimes I've zeroed out, but while I was writing in the log, it changed by a few feet. That's to be expected. So which reading do I take as accurate? The zero reading, or the 3' off reading a bit later?

This also screws up an record keeping...given the error margins inherent with GPS, both with and without WAAS, how do you define "on top of"? Seems to me this should be falling within a certain range, and not hitting an exact point.

Like I said, because of the moving sats and a myriad of other conditions, such as hider placement, execting to be "on top" of the cache 75% of the time isn't realistic.

George

[This message was edited by nincehelser on May 15, 2003 at 10:52 AM.]

May 15, 2003

quote:
Originally posted by Markwell:
There were a couple cachers that had WAAS enabled GPS devices that were 10-15 meters off when it was off. They said they never used their WAAS. They turned their WAAS on and were right on top of the marker (the marker was marked with WAAS on). They swore they would never leave WAAS off again.

Interesting experiment.

Do you have any idea how long it took for WAAS to kick-in once they turned it on?

George

9.5k · May 15, 2003

Fair enough and I agree with your statement of statistical averages. It is, afterall, a moving target in more ways than one. I was just stating what I had noted so far in my ~short~ cache hunting career.

I just added 3 more waypoints to my stats, and the average has dropped down to 64%. Pay attention I did state waypoints as I am including individual waypoints from mulitple cache hides. Out of (now) 10 legal finds, there are 14 waypoints considered. Two of them within 12 minutes of each other yesterday, had me within 25 feet of one and on top of the other.

When do I note? When I'm ready to note my EPE at that moment which means, my initial "On Top" can and does change.

How do I define it? I use a $ for my cache/waypoint icon. The shape is very easily discernable when breaking past the arrowhead icon of my position. If it is completely covered and the cache is at my feet, I'm "On Top or Ground Zero" and the rest becomes an estimate. With 100 foot resolution, and until I'm willing to plop $1,000's on a high end GPS, that's the best I can come up with. It all boils down to a personal decision of when the position is noted.

Personally, I didnt' and don't really expect to be on top 75% or even 60% of the time. Again, my original personal expectation is less than 50% of the time. This is just how the analysis is coming up so far and that was all I stated. As long as it shows to be on top more than not on top, I'll start at GZ first, then expand outward.

Cheers!

TL

May 15, 2003

I leave it enabled all the time. But since you need to actually lock on a WAAS sat, number 33 (positioned above the east coast of Brazil), 35 (positioned just west of Africa), 44 (positioned over the Indian Ocean, but rarely OK for nav), and 47 (positioned over the Pacific Ocean, but also rarely OK for nav), it is rarely actually used. Seems I can only get WAAS correction in wide open areas and/or very clear days in my area. This is probably due to the WAAS sats having a fix position orbit over the equator. Not sure how much of a drain it is, since the GPSr simply is receiving data from another sat and will only use it in position calculations if the sat indicates it is OK to use for navigation, the rest of the time it simply uses the correction info to correct the signals from the other sats that occurs from atmospheric conditions etc... I carry about 8 sets of spare batteries since my radios and digital cam also use AA, so battery drain is rarely a concern for me.

BTW - The sat numbers are Garmin IDs, may be different on other systems.

My mind not only wanders...

Sometimes it leaves completely...

**Namaste**

8.9k · May 15, 2003

quote:
Originally posted by nincehelser:
Do you have any idea how long it took for WAAS to kick-in once they turned it on?

Unfortunately, no. I only heard about the experiment as we were cleaning up from the event, picking up the flags. This was hours after they had done this.

I think this was popular enough of a little side game that we'll probably do it again. I may color code the flags this time with five different colors:

*Garmin No-WAAS

*Garmin WAAS

*Magellan No-WAAS

*Magellan WAAS

*Everyone else

Let's see what happens then.

Markwell

Chicago Geocaching

5.3k · May 15, 2003

quote:
My understanding (and it is a layman's understanding) of the real gain in WAAS is that the station, be it a DGPS ground station or a WAAS satellite, is that their positions are fixed, the satellite being geosynchronous. This improves the accuracy because of the known fixed location and the almanac really doesn't change that much.

Well, your understanding is completely wrong.

There are some excellent explanations of how WAAS works on the Web. I strongly suggest reading some of them. It may make the choice between using and not using clearer.

I always use WAAS; there is no reason not to, unless you're using a Garmin with defective WAAS software. But I think Garmin has fixed the problems in their newest updates.

9.5k · May 15, 2003

quote:
Originally posted by fizzymagic:

quote:
My understanding (and it is a layman's understanding) of the real gain in WAAS is that the station, be it a DGPS ground station or a WAAS satellite, is that their positions are fixed, the satellite being geosynchronous. This improves the accuracy because of the known fixed location and the almanac really doesn't change that much.

Well, your understanding is completely wrong.

There are some excellent explanations of how WAAS works on the Web. I strongly suggest reading some of them. It may make the choice between using and not using clearer.

I always use WAAS; there is no reason not to, unless you're using a Garmin with defective WAAS software. But I think Garmin has fixed the problems in their newest updates.

I did go back and look. I used the wrong terms, but the basic layman's understanding is fundamentally correct.

Error on my part:

DGPS is a different system from WAAS.

I apologize for mixing DGPS and WAAS in the same definition.

A more verbose way of saying "This improves the accuracy because of the known fixed location and the almanac really doesn't change that much." is:

Signals from GPS satellites are picked up by Ground relay stations for WAAS and corrections signals are sent to geosynchronous satellites for WAAS that the GPSr can pick up within the broadcast area for better accuracy. The original approximation was 7 meters veritically and horizontally with improvements over system upgrades. What does change is the Ephemeris data and that is what the correction signal modifies in the GPSr.

Btw... if the ephemeris is less than 30 minutes old in your GPS, your lock will be quicker and is known as a warm start. More than 30 minutes, or cold start, the ephemeris data has to be recollected.

Cheers!

TL

May 15, 2003

Are there Garmin revs that have bad WAAS code?

I've heard a rumor that sometimes you get worse results with WAAS on a Garmin because it gives preference to corrected sats, even though the un-corrected sats have a superior geometry.

I'm not sure how often this situation occurs (if it is true). I'm not even sure how long it takes for all the WAAS data to download.

Anyone know for sure?

George

May 15, 2003

I have a Spor Trak (with WAAS). I wasn't aware it could be turned off. Most of the caches I've found have been within 10' or so. A few that were under heavy tree cover were maybe 20'. That's one disadvantage to living in Texas; we have lots of trees that don't drop their leaves in the fall (cedar and Live Oak).

May 17, 2003

Nope. Never saw where it helped in our area.

1.5k · May 17, 2003

I have from time to time. When it's attached to my cig lighter and mounted to the windshield, it's almost always on. Why? Because it can be, and it's only drawing from my alternator. When I'm placing a cache, or stages to one, I turn WAAS on and wait to check for availability of WAAS correction. If that little 'D' shows up, I wait a few more minutes to let the unit settle, then take my coordinate reading. So far, it's been quite accurate.

Brian

Team A.I.

May 17, 2003

Sure. I use it when I can but I'm not sure it really helps all that much.

9.5k · May 17, 2003

Today, without WAAS, I was consistently 40-60 feet off the waypoint. I'll keep WAAS on.

Cheers!

TL

May 17, 2003

I use WAAS. I usually get 12-14 hours of use from 2 AA batteries

--------------

Changing some folks mind, is like trying to herd cats.

If you have WAAS do you use it while geocaching?

Recommended Posts

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment

Link to comment