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| GeoCommunity Mailing List |
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| Mailing List Archives |
| Subject: | Re: GISList: GPS and powerline question |
| Date: |
02/14/2003 01:24:09 PM |
| From: |
Steven M. Robertson |
|
|
I emailed the Trimble support and Thales Navigation about this issue and one
of Trimble's reps called me and gave an affirmative to whether or not the
elctromagnetic field around powerlines affects GPS recievers. He said one
solution would be to use "offset points". I haven't heard back from Thales
Navigation.
----- Original Message -----
From: "Mohammad A Rajabi" <marajabi@hotmail.com>
To: "Dan McIntyre" <d_mcintyre@site.ntu.edu.au>: <gislist@geocomm.com>
Sent: Thursday, February 13, 2003 10:09 PM
Subject: Re: GISList: GPS and powerline question
> Hi,
>
> I did a Google search and among others I found the followings more
> interesting. Hope it helps.
>
>
> http://www.isaust.org.au/innovation/2001-Spatial_Odyssey/pdf/gibbings.pdf
>
> http://www-aadc.aad.gov.au/spatial_data/gps/gps_capture.asp
>
> http://www.gisdevelopment.net/tutorials/tuman004a.htm
>
>
> Best Wishes
> Mohammad
>
> ======================
> Dept. of Geomatics Eng.
> University of Calgary
> 2500, University Dr., NW
> Calgary, Alberta
> Canada T2N 1N4
> Tel: 403-210-9497
> Fax: 403-284-1980
> ======================
>
>
>
>
>
> ----- Original Message -----
> From: "Dan McIntyre" <d_mcintyre@site.ntu.edu.au>
> To: <gislist@geocomm.com>
> Sent: Thursday, February 13, 2003 3:59 PM
> Subject: RE: GISList: GPS and powerline question
>
>
>
> Apart from personal observations, are there any published studies that
> demonstrate a clear relationship between the proximity of electromagnetic
> sources and compromised GPS performance? Seems like a cloudy issue.
>
> Regards
>
> Dan
>
> --------------------------------------------------------------------------
--
> ------------
> Dan McIntyre
> Research Associate (GIS Analysis)
> Key Centre for Tropical Wildlife Management
> Northern Territory University
> Darwin NT 0909
> Australia
> www.wildlife.ntu.edu.au
> e-mail: dan.mcintyre@ntu.edu.au
> --------------------------------------------------------------------------
--
> ------------
>
>
> --------------------------------------------------------------------------
--
> ------------
>
>
>
> -----Original Message-----
> From: Mohammad A Rajabi [mailto:marajabi@hotmail.com]
> Sent: Friday, 14 February 2003 02:05
> To: Gislist (E-mail)
> Subject: Re: GISList: GPS and powerline question
>
>
> Hi,
>
> I have worked with both handheld and geodetic GPS receivers for over a
> decade as well. In few occasions (not always) I have had problems with
> powerlines.
>
> Powerlines can be a source of trouble or not depending on the relative
> position of the receiver, satellites, and the powerlines as well as the
> powerline electrical specifications and the type of GPS measurement (code
or
> carrier phase). In other words, sometimes you can even have GPS
measurement
> right under powerlines without any problem provided the satellite signals
is
> not passing through the powerline electromagnetic (EM) field. Moreover,
> carrier phase measurements are more disturbed by powerline EM field than
the
> code measurements as the EM field can cause a random jump in phase of the
> satellite signals.
>
> Regards
> Mohammad
>
> ======================
> Dept. of Geomatics Eng.
> University of Calgary
> 2500, University Dr., NW
> Calgary, Alberta
> Canada T2N 1N4
> Tel: 403-210-9497
> Fax: 403-284-1980
> ======================
>
>
>
> ----- Original Message -----
> From: "Neil Havermale" <neilh@redhensystems.com>
> To: "'Mohammad A Rajabi'" <marajabi@hotmail.com>: "virginia michelin"
> <vmichelin@hydroqual.com>: "Gislist (E-mail)" <gislist@geocomm.com>
> Sent: Wednesday, February 12, 2003 10:03 PM
> Subject: RE: GISList: GPS and powerline question
>
>
> I have worked with GPS for over a decade and I have never seen powerlines
of
> any type disrupt GPS. High power microwaves on the other hand are known to
> create problems as will vegetation. The newer units are much more refined
> these days in this regard. If the GPS is handheld, your body as well can
> block satellites between the unit and through your body. My opinion on
the
> GPS "jump" you may be seeing is likely related to partial antenna blockage
> by your body, i.e. a best solution satellite is blocked and a less optimal
> one comes into the solution and a "jump" occurs. Best to put it on a pole
> or staff as high as you head.
>
> Temperature will also have strong affects on batteries. In some cases GPS
> receivers can have temperature calibra
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