[OSM-talk] weird behaviour of a gps instrument

Jochen Topf jochen at remote.org
Mon Aug 4 08:09:32 BST 2008


For a simliar effect see:
http://wiki.openstreetmap.org/index.php/GPS_Dead_Zone

On Mon, Aug 04, 2008 at 12:15:24PM +0530, Kenneth Gonsalves wrote:
> I have two gps instruments made locally (identical) and also a garmin  
> 72. The new instruments are very accurate and reliable nearly  
> everywhere. They are not much affected by clouds, trees and even  
> track from within trains with double glazed windows. But there is one  
> problem. In Coimbatore between latitudes 11.0 and 11.1, these  
> instruments go haywire. On josm I see a string of tracks in the north- 
> south direction, one straight line about 50 kilometers long. As soon  
> as the boundary is crossed, there is no problem. I have not yet  
> measured how far east and west this extends. The fact that it is  
> precisely 0.1 degree where the interference is suggests something man  
> made. This does not affect my garmin 72. One suggestion is that the  
> instrument is picking up some other signals from other satellites.  
> Has anyone experienced anything like this?
> 
> coordinates for the trip:
> 
> 1. moving south, track goes haywire at 11.1 N 76.9372 E and reappears  
> at 11.0 N and 76.9628 E. Again moving north it breaks at 11.0 N and  
> 76.7732 E.

-- 
Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298





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