[OSM-talk] weird behaviour of a gps instrument

[Kenneth Gonsalves]

hi,

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.


-- 
regards

Kenneth Gonsalves
Associate, NRC-FOSS
lawgon at au-kbc.org
http://nrcfosshelpline.in/code/