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Re: GPS for Documenting recording data - RFI

Subject: Re: GPS for Documenting recording data - RFI
From: Wild Sanctuary <>
Date: Tue, 13 Aug 2002 09:56:06 -0700
Curious, then, why two different Garmins (etrex units) gave two 
different readings (altitude and location) from the same position. 
Has the Clinton order been rescinded? We were in the open, and were 
getting signals from 4 different satellites.

BK

>At 06:49 AM 8/13/02 -0700, you wrote:
>>Unless one is using something like a calibrated Trimble (about
>>$15,000USD), accurate GPS readings, forest or no, will be unlikely
>>until the distortion chips are removed.
>>
>>Bernie Krause
>
>None of the units have distortion chips.  The distortion signal,
>proprietary of the US Military, that was intended to destroy accuracy was
>removed years ago by executive order of Bill Clinton, and remains set to
>zero today.
>
>The very accurate Trimble units for surveying have a base station, set at a
>calibrated exact location, which broadcasts its GPS location to the field
>unit on a separate frequency.  This (when the distortion was in effect,
>before Clinton) allowed the field unit to subtract the errors and thus
>provide immediate accurate data.  Now, totally unnecessary.
>
>If you are getting bad locations (more than 10 meters off) from ANY units
>today it is a signal problem, and external antennas might help.
>
>The altitude has never worked properly, and typically give hilarious values
>- - -as we drove around the coastline, of sometimes negative 200
>meters.  Glub, glub.
>
>Marty
>
>
>my very best,
>
>Marty Michener
>MIST Software Associates
>PO Box 269, Hollis, NH 03049
>
>
>coming soon : EnjoyBirds, bird identification software for all AOU area.
>
>
>
>
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-- 

Wild Sanctuary, Inc.
P. O. Box 536
Glen Ellen, California  95442-0536
Tel: (707) 996-6677
Fax: (707) 996-0280
http://www.wildsanctuary.com


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