Originally Posted by TomB
Ghost: GPS does occasionally make mistakes. That's why you have to look at the track logs, not just the top speed, and see if results are consistent.
Sorry Ghost, but when we are talking about 71.5 mph on a green I think you can safely conclude that the GPS is consistenly wrong.
So Tom, I skied an hour today at the touring center on my skating skis. Winding, up and down runs, with names like Leslie's Lunge and ZigZag. At a race pace I'd have a max speed of 35-38 mph and an avearge speed of 12-12.5 mph. The GPS showed a max speed of 27,6 MPH and an average of 10,6. I'd say it worked perfectly, gave totally correct numbers, without a glitch for an hour. So it works on skis on varied terrain.
I then drove 22 miles to the liquor store with the cruise control on 65. The GPS showed
a max speed of 66,4, an average of 57, and a distance pf 21.8. Again, no indication that it was doing anything odd.
In recent years the government turned off the GPS dithering, a function which degraded accuracy on purpose for military exclusivity. Differential GPS corrections became common so it was a waste of time. Since then, I rarely see any spurious results.
So, just when does it fail? On the lift at 10.3 mph? Easy skiing at 25 mph? Big GS turns at 42 mph? In a tuck at 50 mph?
My jacket fits pretty close and hardly flapped at 50. At 60 it did. At the top speeds it sounded like a chain saw. The GPS was within the expected range every run.
Without judging ski trails you have never skied, and skiers you never skied with, why should the GPS be wrong above a certain speed? I can't come up with a reason to doubt it.
Edited by newfydog - Mon, 02 Feb 09 07:46:19 GMT