Waas On/waas Off

[+Huntnlady]

From the Magellan Meridian FAQ:

"WAAS - What it is, do I need it, and can I turn it off?

WAAS stands for Wide Area Augmentation System. This system is still experimental. The Meridian can pick up special WAAS satellites (shown by a "W" on the satellite screen) which transmits various correction factors. There are several ground stations in the US which pick up the GPS signals and calculate these correction factors. If you can pick up a WAAS signal, are relatively close to a ground station, and are in the open (no overhead obstructions), then WAAS may improve accuracy. Sometimes WAAS has been known to decrease accuracy. Turning WAAS off will at least insure more consistent accuracy, and may even help to improve battery life (WAAS calculations take a lot of processing power).

 

To turn off WAAS, with the Meridian turned off, hold down GOTO and NAV and tap the PWR button. In a couple of seconds you should see a box pop up with "00" inside of it. At this point, release GOTO and NAV. Use the direction pad to change the "00" to a "03" and then press ENTER. A few boxes should pop up. Press ENTER to turn a "YES" to a "NO" (all boxes will change simultaneously). You may need to use the three-finger salute (simultaneously GOTO, ESC, and ENTER) to get the unit to turn off. Then, when you turn it back on the WAAS satellites should not be visible in the satellite screen. Note that the boot screen will still say "WAAS."

 

I don't use it and I think I get better coordinates. Maybe I am not near any ground stations. I know my battery life is longer without it.

 

What do you think about using WAAS with your GPSr?

[+sept1c_tank]

Using my etrex vista in Indiana, I can't detect any difference with it on or off, other than a longer battery life. I think it's some kind of conspiracy (probably related to the TB conspiracy) or something, so I just keep it turned off.

[+Cardinal Red]

If every Magellans is that big a PITA to operate, I will never buy one.

Thanks for the Warning.

 

My Garmin in Pennsylvania likes WAAS under the right circumstances.

By that I generally mean, when you have a reasonably good satellite "view" to the Southeast while standing still.

 

And since that is normally not the case, I need to be able to turn it ON and OFF easily.

[+Glenn]

I have a Magellan and I don't notice a difference in battery life with WAAS on vs. off. I do notice a drop in battery life the longer I use the backlight.

 

I've noticed that with WAAS on I'm more consistent. It is easier for me to find the same spot on different days. Also, you don't need a ground station close to you for WAAS to be effective. You just need to be inside the USofA and in view of a WAAS satellite.

[+Glenn]

<snip>

I need to be able to turn it ON and OFF easily.

Why?

[+Spoo]

I have a Magellan SporTrak Topo. This is my third generation unit. Battery life is exceptionally good. I use the WAAS 100% and feel it is worthwhile. I have seen my 'dither' go from 60 feet to 9 feet and with the WAAS down to 3 feet.

 

Want to argue? Remember, I have been using GPS units for over ten years now.

 

I think this is just another one of HuntnLady's forum complaints.

[+Spoo]

I just did a current test on my SporTrak..............

 

Current usage with WAAS and no backlight was 0.080 A. (80 mA)

 

At the normal 1.9 Amp hours that a Duracell gives you, this means the batteries should last 23.75 hours.......that is in line with the 24 hour battery life that manuafacturers list for almost ANY make and model of a current GPSr.

 

Note: Ebited for speeling

Edited July 5, 2005 by Spoo

[+reveritt]

I have a Magellan SporTrak Topo. This is my third generation unit. Battery life is exceptionally good. I use the WAAS 100% and feel it is worthwhile. I have seen my 'dither' go from 60 feet to 9 feet and with the WAAS down to 3 feet.

...

I use the Sporttrak Pro, and I agree 100%.

 

I am not always able to benefit from WAAS in the woods, as the WAAS birds are low on the horizon, but when I cann use it, my accuracy is improved.

 

Battery life is not an issue.

[+EraSeek]

From the Magellan Meridian FAQ:

"WAAS - What it is, do I need it, and can I turn it off?

This system is still experimental.

There are several ground stations in the US

If you can pick up a WAAS signal, are relatively close to a ground station...

Sometimes WAAS has been known to decrease accuracy. Turning WAAS off will at least insure more consistent accuracy,

 

You're kidding! Magellan actually has this on their website?? They need a new review of their info!

 

1. The system is NO LONGER experimental. It is fully functional and has been for several years. Yes, more improvements are coming.

 

2.Several ground stations? Somewhere closer to 25 as I recall.

 

3. This is TOTALLY wrong. You do not need to be close to a ground station. You just have to be in the service area which is modeled, (The US, and then some.)

 

4. Decrease accuracy? It may raise you accuracy number (EPE) for a bit while the data is being gathered, but this is a programmed guestimate and not actual accuracy. Once applied WAAS should only be able to increase accuracy.

 

5. I had heard Magellan does not tell you how to turn it off, and warns against it.

[+tabulator32]

1. The system is NO LONGER experimental. It is fully functional and has been for several years. Yes, more improvements are coming.

 

2.Several ground stations? Somewhere closer to 25 as I recall.

 

3. This is TOTALLY wrong. You do not need to be close to a ground station. You just have to be in the service area which is modeled, (The US, and then some.)

I'm just asking to be sure.

 

Are you saying I should be able to pick up WAAS anywhere in the US and it should be beneficial to my readings?

 

Where are the WAAS ground stations?

 

Just curious.

 

[+EraSeek]

As long as you have a open veiw of one of the two WAAS sats (not hidden by mountain, trees, buildings) then Yes.

 

Here is a link to some good information. The first graphic shows the ground stations. These stations only gather information and sends datd to the master stations. The master station creates a correction model and sends this model of corrections to the WAAS sats. The WAAS sats broadcast this almanac to your GPS. Your GPS figures out where it is in the grid and applies the correct corrections.

http://www.gpsinformation.org/dale/dgps.htm#waas

[+Cardinal Red]

Bushwhacked Glenn Posted on Jul 4 2005, 04:55 PM

(Cardinal Red @ Jul 4 2005, 07:36 AM)

<snip>

I need to be able to turn it ON and OFF easily. 

 

Why?

 

OK. That's a fair question. Here's my answer.

 

Huntnlady Posted on Jul 4 2005, 12:17 PM

<snip>

Sometimes WAAS has been known to decrease accuracy. Turning WAAS off will at least insure more consistent accuracy, and may even help to improve battery life (WAAS calculations take a lot of processing power).

 

I have no proof any of that is true. Perhaps it was true early on, and isn't any more. I had read the same basic information somewhere before (not from Magellan). The only time I use WAAS while moving is in my Truck, on external Power and Antenna to pick up an Almanac Update. While I can't prove it, I just feel I get better performance without WAAS while moving through tree cover. Since I don't need precision while hiking and it's fairly easy to turn ON and OFF, I generally don't use it unless I am trying to get a good fix when stopped (or circling a Cache area). It would be even better if it had a shortcut ON/OFF Toggle like the Electronic Compass.

 

I just can't see buying a unit where I can't EASILY decide what I want, even if I don't need it.

[+EraSeek]

Here is a display of current optimal coverage with verticle confidence.

http://www.nstb.tc.faa.gov/vpl.html

 

By the way, Hawaii is also covered by WAAS.

[+reveritt]

There are numerous ground stations in the US. They are located at well-surveyed locations, and use the difference between their known locations and their apparent GPS locations to calculate corrections to GPS positions. Some of the corrections (such as orbital wobble) are valid for all locations, but at least one correction, having to do with atmospheric conditions, is somewhat "local", and the closer you are to a ground station, the more likely the calculated propagation delay model will be accurate for your location.

 

The results of the WAAS calculations are transmitted to WAAS sattelites in geosynchronous orbit above the equator. To be able to receive the WAAS signal, you must not be to badly blocked on your southern horizon, but the signals are available throughout the continental US.

[+EraSeek]

There are numerous ground stations in the US.  They are located at well-surveyed locations, and use the difference between their known locations and their apparent GPS locations to calculate corrections to GPS positions.  Some of the corrections (such as orbital wobble) are valid for all locations, but at least one correction, having to do with atmospheric conditions, is somewhat "local", and the closer you are to a ground station, the more likely the calculated propagation delay model will be accurate for your location.

 

The results of the WAAS calculations are transmitted to WAAS sattelites in geosynchronous orbit above the equator.  To be able to receive the WAAS signal, you must not be to badly blocked on your southern horizon, but the signals are available throughout the continental US.

"Some of the corrections (such as orbital wobble) are valid for all locations,"

 

Yes, this is true even outside the service area as long as you have the WAAS sats in veiw.

 

"but at least one correction, having to do with atmospheric conditions, is somewhat "local", and the closer you are to a ground station, the more likely the calculated propagation delay model will be accurate for your location"

 

This is the corrections for the ionosphere. Once the ground station transmit their data to the Master station the ground station plays no other part. The master makes a model, a grid of corrections. It fills in the blanks between the ground station data. The relationship of accurate corrections for the active ionosphere to the nearness of ground stations at this point is minimal.

 

 

Edit: Here is a fine example of how the ionosphere affects the US over the coarse of a day. Note, less activity at night. Note: this is also much of how the correction grid would look and operate, with you GPS figureing out where the closest cross-of-threads in the net is and appling those corrections.

http://gpsinformation.net/exe/iono-day.gif

Edited July 5, 2005 by EraSeek

[+Kllr Wolf]

I dont understand what the colors mean on the first link you posted EraSeek. Do the cooler colors represent better accuracy or worse? i am guessing better by the area covered, but it still confuses me.

[+Renegade Knight]

I get better accuracy with it, but it also slows down my refresh rate so I leave it off.

[+JohnnyVegas]

I just leave WAAS on, there in nothing to be gained by turning WAAS off. As far as bettery drain or having the refresh rate slow down, this can also be caused by loading a large map into the GPS memory.

 

As far as huntlady not being near any good ground stations, there is no need to be near a ground station. I have cached in the Napa valley and I have not had a problem getting a good WAAS signal.

[+Huntnlady]

I have a Magellan SporTrak Topo. This is my third generation unit. Battery life is exceptionally good. I use the WAAS 100% and feel it is worthwhile. I have seen my 'dither' go from 60 feet to 9 feet and with the WAAS down to 3 feet.

 

Want to argue? Remember, I have been using GPS units for over ten years now.

 

I think this is just another one of HuntnLady's forum complaints.

Gee, what have you got against lady hunters? I quoted Magellan, gave my viewpoint, and asked for other viewpoints. Does that sound like complaining?

 

What did I ever do to you?

[+Spoo]

Gee, what have you got against lady hunters?  I quoted Magellan, gave my viewpoint, and asked for other viewpoints.  Does that sound like complaining?

 

What did I ever do to you?

Because you do not know what you are talking about. You read an outdated disclaimer that Magellan protects itself with.......and there is NO WAY that WAAS usage affects battery life. It's all in your head.

 

As has been noted by others, up above, WAAS can be used anywhere and the new expanded technology can ONLY enhance position.

 

I am discouraged by people that do not take two minutes to research the internet for the latest information but instead make blind statements that are not founded.

 

Go here: http://gpsinformation.net/exe/waas.html

 

As can be seen, all but the very central U.S. can grab TWO WAAS units which can only benefit accuracy.

 

As for battery life, This is like saying your radio reciever uses more power in the FM mode then it does in the AM mode.

Edited July 6, 2005 by Spoo

[+sbell111]

Ummm, how about a nice, deep breath?

[+EraSeek]

Go here: http://gpsinformation.net/exe/waas.html

 

As can be seen, all but the very central U.S. can grab TWO WAAS units which can only benefit accuracy.

 

Actually the yellow sat there is not waas. It is europes version of WAAS, ENOS. Therefore the only place you can get both WAAS sats in the US is in the west, (the one over the pacific and the one over Brazil). You only need to veiw one sats, but having two is easier to get at least one.

[+sbell111]

Actually the yellow sat there is not waas. It is europes version of WAAS, ENOS. ...

I thought that was the deputy on 'Dukes of Hazzard'?

[+EraSeek]

I dont understand what the colors mean on the first link you posted  EraSeek.  Do the cooler colors represent better accuracy or worse?  i am guessing better by the area covered, but it still confuses me.

As I understand it, this graphic shows the real-time confidence level for verticle accuracy of WAAS, basically for aircraft. Thus, it shows a higher standard then what we would use as cachers, not being so concerned with the verticle. Thus, for us, it shows when and where WAAS is most effective in terms of coverage and corrections. Blue is good. Yellow-red, your getting outside the effective coverage area.

 

Just for interest sake, here is the total coverage area of the WAAS sat and their corrections, WITHOUT IONOSPHERIC CORRECTIONS which just covers most of North America. http://www.nstb.tc.faa.gov/npa.html This would cover things like clock errors and relativity adjustments.

Edited July 7, 2005 by EraSeek

[+EraSeek]

I'd like to voice my "opinion" on some of the WAAS issues. Mostly not based on hard data, but certainly in the realm of educated opinion.

 

1. WAAS does use more battery power because there is more processing going on. However, my feeling is that the additional power draw is not great. In fact minimal. Auto routing probably draws more.

 

2. Map drawing is probably slowed some by WAAS, however autorouting probably slows map drawing more. The two combined is probably why WAAS gets a bad rap on this.

 

3. WAAS always improves accuracy once APPLIED. As WAAS is applied you will often see the EPE or accuracy reading jump up for a bit. This is due to processing and is not true accuracy anyway. Testing WAAS and Non-WAAS on a benchmark convinced me that WAAS does increase accuracy by about 40%, when you can get it. However, the increase is NOT huge or critical for geocaching.

 

I amost always use it. I do turn it off when I know I can't get it, such as in the woods. By doing this I free up 2 channels, and processing power is conserved.

 

All my humble opinion.