GPSMAP 67i 1st Test
GPSMAP 67i 1st Test
Notice the 67i did much better in the second test lower in this notebook where it had a nearly full view of the sky than it did in the first test immediatleyly below where it had only a partial view of the sky and may have been subject to household electrical interference. Of the 1235 horizontal position measurements in the second test with a good view of the sky, 1037 were within (84% confidence for PDF illustrated below). The worst discrepancy among all measurements in that test was . Also, standard deviation of elevation . That was much better when compared to the first test where the standard deviation on horizontal position was 15.0044 m.
It’s tempting to focus on ideal-conditions performance as a measure of utility. I think that is misguided. The concept behind the 67i is to tell users roughly where they are when no other backup is available, not precisely where they might otherwise be. So what matter more to me than ideal-condition accuracy, are attributes like battery life, component reliability, firmware quality, indestructibility, light weight, and ability to navigate under tree canopies in obstructive terrain. So performance thought poor by some from inside my kitchen in the first test is fine in my opinion. Even the worst single measurement recorded, 81 meters from the mean, is close enough for me to find a lost trail or for rescuers to find me. And as for communication, I'm more concerned with the certainty than speed.
--Jay Gourley
±
2.46565
m
15.4616
m
8.25595
m
It’s tempting to focus on ideal-conditions performance as a measure of utility. I think that is misguided. The concept behind the 67i is to tell users roughly where they are when no other backup is available, not precisely where they might otherwise be. So what matter more to me than ideal-condition accuracy, are attributes like battery life, component reliability, firmware quality, indestructibility, light weight, and ability to navigate under tree canopies in obstructive terrain. So performance thought poor by some from inside my kitchen in the first test is fine in my opinion. Even the worst single measurement recorded, 81 meters from the mean, is close enough for me to find a lost trail or for rescuers to find me. And as for communication, I'm more concerned with the certainty than speed.
--Jay Gourley
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Hyperlink["https://www.wolframcloud.com/obj/jgourle20/Published/Garm%2067i%20test.nb"]
Inside house at window with about 1/4 sky exposure in expedition mode
Inside house at window with about 1/4 sky exposure in expedition mode
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Screenshot from BaseCamp
ListPlot[distFromMean,PlotLabel->"Distance from Mean over Time",AxesLabel->{"Ordered measurements","Divergence in Meters"}]
(*Verticalchangebetweenadjacentdatapoints*)Histogram[Table[g67i[[i,5]]-g67i[[i-1,5]],{i,2,Length[g67i]}]]
GPSMAP 67i 2nd Test
GPSMAP 67i 2nd Test
Outdoors with about 4/5 sky exposure in multi-band mode
Outdoors with about 4/5 sky exposure in multi-band mode
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Screenshot from BaseCamp
