On Tue, Jun 24, 2003 at 04:55:03PM -0700, Bill Malvey wrote: > For you LoLo owners (and I will be one soon), does the LoLo read altitude > above sea level (ASL) or above ground level (AGL).
I'm sure Sheldon will answer properly, but it just appears to be a pressure sensor, data logger, some glue, and lots and lots of experimentation and integration. We're paying mostly for the latter, which is quite fine by me. The actual data you download from the device is converted into altitude with some simple-looking and adjustable formulas, and there's a convenient way to normalize the ground level in the software. > Does it have a way to zero it or correct for barometric pressure? Just > curious. Thanks It "zeros" when you first start it up, as far as I can tell. Obviously with a pressure-only altimeter (just like in a real plane) if you fly to a place with a different ambient air pressure or if the weather changes a whole lot things will be skewed a bit. In our application it should be easy to check for this by comparing the difference between "ground level" at different points during the day. FWIW, I took my Alti2 from ATL -> Las Vegas -> San Diego, and the cabin pressure was around 6200' at cruising altitude on the first leg and around 5000' on the second leg. The ground readings look sane (i.e. San Diego is lower than Atlanta, etc) and I used a 6 second sampling rate. Security didn't even stop on the 4-cell pack shrink-wrapped with an Alti2 on it that was blinking. :) -Peter -- Peter Jensen ... http://www.diff.net/peter ... [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
