bollar

This link should take you to all of the images included in the patent: http://patimg2.uspto.gov/.piw?Docid=071421...View+first+page Good luck pasting all of that into the browser...

Assuming it was calibrated at the beginning of the test, or enough time has elapsed to allow auto-calibration to work, it will be 2000 meters or something very close to it, depending on how recent and significant the change in barometric pressure.

And, while we're at it, I did these tests a few years ago when the Edge 305 was introduced. The Edge 305 and 705, as you probably know, have barometric altimeters, but they can't be calibrated. I posted a plot of four Garmin devices here: http://www.bollar.org/images/edge305elevations.pdf In short, the barometric Garmins started off with the same deviation from true altitude and converged on true altitude over time, which took about an hour. I never did a test to see how long this would take if the GPS was left on but motionless before the ride. Other thoughts I had about the Edge 305, which was cutting edge at the time with the SiRFstarIII chipset are here: http://www.bollar.org/edge305.htm

Sorry to resurrect this old thread, but Garmin's algorithm is patented, and is therefore accessible to us. You mathematicians can have a field-day with this link: http://www.patentstorm.us/patents/7142152/fulltext.html