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Cedar Rapids, Iowa | I've often heard SF1 being compared to WAAS, but after testing, I can say that SF1 is significantly better than WAAS.
Results: (Note there are two tabs. The more detailed results are on the second tab.)
http://spreadsheets.google.com/pub?key=pQEFqfMI4UEND1BBDtyJsag
Be aware that these tests show position drift over a 24 hour period. What I can't tell from these tests is how much position drift there is over a smaller time window such as 15 minutes.
WAAS on a Trimble 252 showed a horizontal drift (3 sigma, average of 7 tests) of 30.84 inches.
SF1 on an iTC was at 11.25 inches.
SF1 exhibited the same drift pattern that SF2 did - they both seem to drift to the West and to the South East. I still have no idea why that is the case.
What I found really odd was that SF1 showed better results on the vertical axis than SF2 did. This leads me to wonder if there are any accuracy improvements in the new firmware. I had to use v3.40N to get NMEA out of the receiver on SF1. The receiver on SF2 was running older code (v3.05D) at the time of testing, which was production code released some time in 2008. For both the SF1 and SF2 tests, the iTC tilt compensation was disabled.
-Lance | |
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Static Accuracy Testing of SF1
