[time-nuts] nuts about position

Mark Sims holrum at hotmail.com
Wed May 30 15:46:48 EDT 2018

Ok, I did the experiment.  I took an 8 hour M8T RINEX file with GPS,SBAS,GLONASS,GALILEO data in it.  I then used to TEQC to extract GPS only and GLONASS only data (CSRS-PPP ignores SBAS and GALILEO data).   The 95% confidence error ellipse estimates ("rapid" orbits) were:

GPS+GLONASS:    lat 0.245m    lon 0.219m    alt 0.582m
GPS ONLY:             lat 0.269m    lon 0.239m    alt 0.616m
GLONASS ONLY:   lat 0.610m    lon 0.755m    alt 1.835m

Conclusion... if you are just interested in an accurate antenna position,  a $25 LEA-5T should do just fine.  GLONASS brings very little benefit (call it an inch) to the party.  24 hours of observations can reduce those numbers by around 50%   I used one of those $70 Chinese L1/L2/GLONASS/BEIDOU antennas from Ebay.   Note that my antenna location/environment is HORRIBLE... 

Things might change if you get into expensive L1+L2(or L5) receivers.

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