Ahhhhhhh, That's the key. Ublox is much more suited to consider for altitude reporting. Anything with Sirf in the chipset name, I wouldn't consider accurate for a dynamic altitude situation. Good for position only. (Yeah, I know no AM product uses that device but for the purposes of finding a rocket Sirf O.K.) Kurt Savegnago -------------------------------------------- On Tue, 7/14/15, Bdale Garbee <[email protected]> wrote:
Subject: Re: [altusmetrum] TeleMega barometric altitude vs GPS Height To: "David Abmayr" <[email protected]>, "Altus Metrum" <[email protected]> Date: Tuesday, July 14, 2015, 11:10 AM David Abmayr <[email protected]> writes: > The reason I ask it that the barometric altitude reads 9700 ft, but > the GPS reported 10,240 ft. That's not unusual. Adrian used to go pull atmospheric sounding data From NCAR after launches to re-compute baro altitudes with something closer to reality than the standard model of the atmosphere we all use for in-device firmware. Even then, though, using baro pressure as a proxy for altitude is still just an approximation. > Most of my > flights have been with the TeleMetrum 1.2, and the GPS clearly doesn't get > a good fix until well after apogee. My TeleMetrum 2.0 and TeleMega seem to > work much better, with good fixes at apogee. Right. The Venus chips we used on early TeleMetrum boards worked fine for finding an airframe after flight, but their firmware did not behave well in high dynamic situations. The uBlox parts we use now are much better suited for rocketry. This past weekend at NCR North, for example, son Robert and I had great GPS traces on all of our flights using a mix of TeleMetrum v2 and TeleMega boards. Bdale -----Inline Attachment Follows----- _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
