From Sacramento To Tibet In An Instant!!!

[+Bob Blaylock]

  From time to time, my yellow eTrex experiences some odd glitch, that puts me momentarily a very great distance from my actual location.  I wind up with stored statistics that show that I — on foot — achieved a maximum speed in the thousands of miles per hour, having covered thousands or tens of thousands of miles in a short time.

 

  Just yesterday, I had the most spectacular of these glitches.  I was coming out of a mall, and looking for my car, which I had waypointed before I went in.  I was watching the advanced skyview display, watching for satellites to lock in  Just as the third satellite was locking in, the view changed drastically.  Most of the satellites that appeared on the display vanished, and were replaced by a smaller number of entirely different satellites, from which the eTrex was not receiving any signals.

 

  I found the car the stone-age way, handed the eTrex to my wife, and drove home.  On arriving home, we noted that the eTrex had still not locked on to any satellites.

 

  On further examination, I found that the eTrex thought that its last known location was…

 

    N 30° 41' 28.8"

    E 89° 50' 25.0"

 

…which turns out to be in Tibet.

 

  Usually, my eTrex recovers quickly from these glitches, producing a record which seems to show that in some instant, I travelled some very great distance, then almost immediately traveled back to my previous position.  This time, it didn't.  It went to Tibet, and was stuck there, unable to see the satellites that it thought it should see from there.  I had to shut it down, turn it back on, wait for it to complain about not being able to get a signal, and answer “Yes” when it asked if I had travelled a great distance since it was last on, to get it to do its broader search to find itself back in Sacramento.

 

 

  So, what causes this kind of glitch?  Is this something that most GPSrs experience from time to time, is it something unique to eTrex units, or is there some odd defect in my own specific eTrex that causes this?  Are other GPSrs affected in different ways by this sort of glitch?

[Neo_Geo]

Yep! Had it happen to me. I was standing on a street corner in Washington, DC, and my eTrex Legend had me zooming along through Canada at over 1,000 M.P.H. and accellerating!

 

Read all about it:

Standing Still At 1,000 M.P.H.!!!

Edited December 14, 2004 by Neo_Geo

[+bradandangela.com]

Maybe you really did travel that far and back in an instant, and now that you have your GPSr, you actually notice it. Did you experience any dizziness or anything when this happened?

[+Rubberhead]

I wind up with stored statistics that show that I — on foot — achieved a maximum speed in the thousands of miles per hour, having covered thousands or tens of thousands of miles in a short time.

Please use your superhuman powers for good, not evil. Oh yeah, by the way, you can't tell your girlfriend about them either.

 

:->)

[+AtoZ]

Check your batteries, update the firmware in you GPSr and if you feel dizzy put you head between your knees.

cheers

if all else fails call garmin

[+JohnnyVegas]

one of the malls in the sacremento area has a worm hole that may have been the problem. I think it's at the Galleria mall in Roseville

[+Sputnik 57]

Let's see, worm hole, space aliens, or problem with your almanac. It's probably one of those. Just in case its the last one, you may want to try a hard reset, followed by a half hour or so of clear sky to let the unit reacquire its almanac data.

 

Of course, this is just a guess.

[+Kewaneh & Shark]

... Just as the third satellite was locking in, the view changed drastically...

To locate a position, the GPSr needs signals from a minimum of four satellites. Mathmatically, signals from only three satellites actually give two possible positions, the first being at (or near) the real coordinates, and the second being in the neighborhood of 24,000 miles above the real coordinates (or about 12,000 miles above the satellites which are about 12,000 miles above the earth). It's possible that when your GPSr locked onto the third satellite, it jumped to the wrong coordinate (instead of remembering where it was), or tried to interpolate a coordinate from the data - the result being Tibet. Once the GPSr thought it was there, it began looking for the satellites that were in the sky over Tibet, which is why the set and position of the satellites changed. The only work around that I know of is to re-initialize the GPSr, like you did.

 

Like AtoZed said, it could be a firmware issue. The programming in the GPSrs is supposed to filter out the 'bad math' from the good when calculating a position, but even well written programs have glitches. Thank goodness for updates. If you're counting your steps every day, where the global bouncing could be critical, or if you just don't like visiting exotic places at less-than-a-moment's notice, check on a firmware update or call Garmin. If the GPSr works fine otherwise and you don't mind its personality qwirk, don't worry about it. Just keep your bags packed for your next trip and enjoy the ride.

 

Keep on Caching! - Kewaneh

[+Tervas]

Don't really know if this is just a coincidence but once I deleted the waypoint my eTrex was navigating to. Result was that the GPSr told me I was heading north at about 640 km/H speed

Had to turn the power off and on a couple of times before the gadget became sane again.

[+Bob Blaylock]

Like AtoZed said, it could be a firmware issue.  The programming in the GPSrs is supposed to filter out the 'bad math' from the good when calculating a position, but even well written programs have glitches.  Thank goodness for updates.  If you're counting your steps every day, where the global bouncing could be critical, or if you just don't like visiting exotic places at less-than-a-moment's notice, check on a firmware update or call Garmin.

  My eTrex has version 2.14 of the firmware, which appears to be the latest version.