- From: Alexander Mayrhofer <alexander.mayrhofer@nic.at>
- Date: Thu, 22 Jan 2009 10:57:04 +0100
- To: "Thomson, Martin" <Martin.Thomson@andrew.com>, "Erik Wilde" <dret@berkeley.edu>, <public-geolocation@w3.org>
> Alright. Let's go with altitude. I take each source and > quantify its error. The barometric altimeter is subject to > pressure variations so it is off less than 200m, 95% of the > time; I probably have to work this out ahead of time. The > GPS directly provides altitude uncertainty, which I scale to > the same confidence. Plus (warning - slightly OT) - barometric altitude is completely useless in some situations, most prominently in the cabin of a commercial airplane. Some GPS receivers insist on using the barometic altitude (and ignore GPS altitude), which makes your GPS track stick at 2000 Meters, essentially rendering the elevation measurement completely unusable, and off by several kilometers. Example here: http://timatio.com/traces/17225-hamburg-wien Alex
Received on Thursday, 22 January 2009 10:09:46 UTC