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| John Pointon here from OmniSTAR.
It's not for me to list the mods. However, they included hardware changes to ensure proper omnidirectional gain in the antenna.
Receivers which were affected by these issues could drop GPS satellites and the OmniSTAR satellite depending on orientation which resulted in unreliable performance (for which OmniSTAR, naturally, was blamed!).
As far as accuracy is concerned, there is so much looseness in the terms* being used that it's hard to know what to say. (*I won't call them 'definitions').
I'm currently looking at two typical plots in .pdf format which show a week's worth of data using OmniSTAR XP and OmniSTAR HP. Unfortunately I don't see how to attach them, they're ~ 550K each.
One is from an HP monitor located in Sioux Falls, SD. The standard deviation of Lat and long are about 2.8 cms, or about 1 inch. The 95% Circular Error is 6 cms - or slightly more than 2 inches.
The next plot is an OmniSTAR XP monitor located in Fargo, ND. It has
standard deviations of about 3.3 to 4 cms, or a little less than 2 inches.
It has a 95% Circular Error of 8 cms, or about 3 inches.
So over the long term you can expect errors up to about 3 inches with OmniSTAR XP, and about 2 inches with OmniSTAR HP. "Pass to pass" (whatever that is!) should be better.
I'd be happy to e-mail these plots for review to anyone interested (we generate plots daily). Just e-mail me at [email protected]
From our data I'd say that the differences in accuracy between dual frequency OmniSTAR and RTK tend to be overstated.
Edited by jpointon 3/13/2007 14:16
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Trimble 252 recall... what did they do and do you notice any difference?
