GPS off by 10feet?

[RWillieK]

We went out on two Caches today, and both waypoints were about ten feet off....

 

Anything I can do to adjust this?

 

Robbie

[+DustyJacket]

You cannot.

Civilian recreational GPS receivers best accuracy is about 10 feet.

 

Plus, you have to realize the cache hider's GPS is going to have some error as well.

 

Sometimes you are right on, and other times you are 30-40 feet away.

 

DustyJacket

Not all those that wander are lost. But in my case...

[+Hard Oiler]

Ten feet is doing great - adjust nothing (and there is nothing to adjust) - you're just lucky it's not thirty. Try marking a spot in your back yard and using your GPS to go to it at different times of the day and different days of the week. You'll soon realise that even the same GPSr varies. If you always got to within 10 feet of the cache geocaching would be no fun at all

[Team BooneDog]

What Hard Oiler said

 

10 feet is extremely accurate to be within a cache. Consider yourself lucky to get that close 2 times in a row

 

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

[+EraSeek]

Gees! Think how far away those sats are! What fantastic technology to get you within an easy stones throw!

 

 

"See the wonderous works of Providence! The uncertainty of human things!" Geo.Washington

[Bender]

You could get longer arms?!?!?

 

Bender

[+Bloencustoms]

Well, you could look at it from a navigation standpoint. If you mark your car and go hiking, then return to within ten feet and can't find the car...

 

"Searching with my good eye closed"

[Kerry.]

10 feet now that's a bit of a worry should have been more like 20 or 30 or 40 feet

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[3fros]

My sister works for a company that does road construction. She uses one of the Trimble receivers all day long. Anyway, her boss had Trimble come out and figure out what was wrong because it was 6cm (or about 2.4") off and is supposed to be within 1cm. Of course they did pay a lot of money for the accuracy.

 

I think they found the error was in the data provided by the state DOT and not the GPSr, but don't quote me on that.

[+smithdw]

I've been to caches that have the coords 'off' from my GPSr by 100'. The reading you get with a consumer-greade GPSr will vary depending on the position of the satellites, signal strength (cloudy, rain, snow, trees, etc) and even in the way you hold it (your body may be blocking reception from another satellite). As you get more experienced, you will start noticing likely hiding spots near the area where the GPS will lead you to. Also, some geocachers seem to hide caches in similar places. We have locals that will usually hide caches in either trees, logs, rocks, bushes, etc. If I am going for a certain cache, I will look at who hid it and then I know where a likely hiding spot will be. There are exceptions though. If I could get 10' accuracy on every cache, I would be really happy.

[3fros]

quote:

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Originally posted by smithdw:

...and even in the way you hold it (your body may be blocking reception from another satellite).

---

 

Another reason to buy one with a quad-helix antenna so you can hold it in the vertical position at eye level or above and pick up that satellite behind you.

[Kerry.]

quote:

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Originally posted by 3fros:

quote:

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Originally posted by smithdw:

...and even in the way you hold it (your body may be blocking reception from another satellite).

---

 

.... and pick up that satellite behind you.

---

 

That why with a handheld if one tries to face the equator when possible this reduces that possibility, with any antenna.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[3fros]

quote:

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Originally posted by Kerry:

That why with a handheld if one tries to face the equator when possible this reduces that possibility, with any antenna.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

---

 

Huh?

The satellites aren't all around the equator.

From Garmin

[Kerry.]

quote:

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Originally posted by 3fros:

Huh?

The satellites aren't all around the equator.

From http://www.garmin.com/aboutGPS/

http://www.garmin.com/graphics/24satellite.jpg

---

 

No, there not all around the equator but then there's NONE over the poles either, some call this the "scull cap" effect. So if there's none over the poles (north or south) then facing the equator puts that void area (extent depends a little on ones Lat) basically behind you.

 

Garmin is a bit generic in their depiction, might look nice but From Me, the actual satellite tracks over the pole. What one would see if standing at 90 deg N, basically no sats above 45 degrees for the full 360 degree horizon.

 

everybody keeps telling me where to go

 

[This message was edited by Kerry on May 13, 2003 at 07:17 PM.]

[+EraSeek]

Here's another view of the ground tracks:

 

"See the wonderous works of Providence! The uncertainty of human things!" Geo.Washington

[3fros]

Now I get it. Garmins picture was messing me up. I thought you were saying that they all went around the earth at the equator, but I can see them going on a sin curve like the shuttle does which would leave them mostly toward the equator and away from the poles.