Magellan SporTrak -- benefit to turning WAAS off?

[+user13371]

I've read the "secret" menu options to turn off WAAS on Magellan receivers. Under what circumstances is this beneficial?

 

Does turning off WAAS on the Magellan improve battery life? If so, by how much?

 

In areas of poor or no WAAS reception, does disabling it on the GPS improve accuracy?

 

In areas with acceptable WAAS coverage, how bad of a hit is it against accuracy to turn WAAS off?

[dave and jaime]

well, i dont have a waas enable reciever because in my area there is no waas coverage by either a grs or sat. however ive borrowed several waas enabled recievers from the gis lab and have found that enabling waas tends to leads to more power comsunption. check out this thread for a test we did just for the hell of it upon hearing a rumour.

 

asides from that a study was done by some grad student at unb that showed enabling waas if there are no valid corrections can adversely affect the overall accuracy of your gps under certain circumstances.

 

'Get to the point---speak English!!!!'

[+Renegade Knight]

WAAS can noticibly slow down your GPS's response. While I have a garmin, I can tell the difference and turn it off.

 

On your magellan you may not notice so much for the same reason that most magellan owners tend to overshoot the cache then come back.

 

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Wherever you go there you are.

[+user13371]

quote:

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Originally posted by Renegade Knight:

On your magellan you may not notice so much for the same reason that most magellan owners tend to overshoot the cache then come back.

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Huh? Didn't understand this. Why do Magellan users tend to overshoot?

[+Renegade Knight]

quote:

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Originally posted by Lee David Rimar:

quote:

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Originally posted by Renegade Knight:

On your magellan you may not notice so much for the same reason that most magellan owners tend to overshoot the cache then come back.

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Huh? Didn't understand this. Why do Magellan users tend to overshoot?

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It has to to with how Magellans work with the satalite information. My understanding is that it uses a moving average of sorts. thus as you slow down getting close to the cache, it doesn't really factor that in right away due to the moving average. Thus you overshoot and then as it catches up to you moves you back to where you wanted to be.

 

Maybe someone else can explain it better.

 

I'm not sure why magellan does this but I do know it gives you an advantage when you lose signal. My garmin will puke and stop while the magellan will move on with false infofrmation until the signal loss catches up to it. I have seen a situation where this was an advantage over the garmin.

 

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Wherever you go there you are.

[+phantom4099]

quote:

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Originally posted by Renegade Knight:

quote:

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Originally posted by Lee David Rimar:

quote:

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Originally posted by Renegade Knight:

On your magellan you may not notice so much for the same reason that most magellan owners tend to overshoot the cache then come back.

---

 

Huh? Didn't understand this. Why do Magellan users tend to overshoot?

---

 

It has to to with how Magellans work with the satalite information. My understanding is that it uses a moving average of sorts. thus as you slow down getting close to the cache, it doesn't really factor that in right away due to the moving average. Thus you overshoot and then as it catches up to you moves you back to where you wanted to be.

 

Maybe someone else can explain it better.

 

I'm not sure why magellan does this but I do know it gives you an advantage when you lose signal. My garmin will puke and stop while the magellan will move on with false infofrmation until the signal loss catches up to it. I have seen a situation where this was an advantage over the garmin.

 

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Wherever you go there you are.

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I don't notice that when I go back to my own waypoints, or use it for any thing else.

 

Wyatt W.

 

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

[+TotemLake]

You can move the debate, but you can't hide from it.

 

quote:

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Originally posted by Renegade Knight:

It has to to with how Magellans work with the satalite information. My understanding is that it uses a moving average of sorts. thus as you slow down getting close to the cache, it doesn't really factor that in right away due to the moving average. Thus you overshoot and then as it catches up to you moves you back to where you wanted to be.

 

Maybe someone else can explain it better.

 

I'm not sure why magellan does this but I do know it gives you an advantage when you lose signal. My garmin will puke and stop while the magellan will move on with false infofrmation until the signal loss catches up to it. I have seen a situation where this was an advantage over the garmin.

 

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Wherever you go there you are.

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Actually, Renegade Knight, when I went to the manual to read about the averaging, it actually takes place at or near the speed 0.0 .

 

As for false information, it will provide a 2D fix with 3 satellites which will provide bad altitude info, and 3D fix at 4 or more satellites which will will provide better altitude info, and indicate a loss of signal at 2 or less satellites. Where does the false information come in that Garmin doesn't do?

 

Cheers!

TL

[+Renegade Knight]

There are two threads going on here.

 

Autoaverating like you said happens with the Magellans at or near zero speed.

 

How the magellans use their data that causes most magellans users to overshoot the cache (unless they figure out how to compensate) is a different thing. I thought it had to do with a running average of your location.

 

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Wherever you go there you are.

[+TX Hokie]

I have a SporTrak Pro, and whatever the reason, I do find that I tend to overshoot caches. I just came from one where the cache was only about 3 feet to the left of the trail, but I kept going about 50 feet or so past it. Once I stopped and started walking back, it put me in the right spot. Annoying, but not the end of the world. After all, if geocaching were easy, what fun would that be?