[time-nuts] nuts about position
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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