[OSM-talk] GPS Accuracy under Forest Canopy

[Liz]

On Tue, 11 Aug 2009, Apollinaris Schoell wrote:
> compared to a SiRF III powered the eTrex is pretty lame in accuracy.  
> but it uses less power and runs twice as long on a set of batteries
ok, so I'm in the rich guys list.
I have an older etrex, the MSO has the newer etrex with the more accurate chip 
http://en.wikipedia.org/wiki/SiRFstar_III
i also have a Neo Freerunner, which is more accurate with the Antaris 4 chip
and we have been obtaining dataloggers with much newer chips and greater 
accuracy than any of those chips, where I have been able to see my trace down 
each side of the road distinctly on an outward and return journey
These have been based on Mediatek MTK chips

I have tried the photoMate i-887 inside a shopping cnetre building and think i 
can get enough traces to map inside that building, but not the carpark below. 
http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=67511
http://www.gpspassion.com/fr/articles.asp?id=175&page=5

motto
try to get the newest sort of chip to track places with very poor signal