He was asking about TeleMini specifically, which only has barometric sensor, no accelerometers.
Looks like a textbook flight there. -bryan On Mon, Apr 2, 2012 at 5:49 AM, Eric Weder <[email protected]> wrote: > If it ain't broke don't "fix" it by wasting code on superstitions. If the > Telemini code uses the same algorithms as Telemetrum, I'd say you have it > covered. > > I flew my Telemetrum last July 1 to 375 m/s (Mach 1.1), with no problems. > It > was backing up my Raven2, and did a fine job. What a stress-reliever it was > to know that deployment was successful while the rocket was 5 km overhead, > and that it would be easy to find it again even if we didn't see it come > down. Don't know if this list allows attachments, I've included a PDF of > the > flight results and my .eeprom file. > > Regards, > Eric > > Eric Weder > [email protected] > T +1(403)337-1965 | M +1(403)863-9617 > > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Keith Packard > Sent: Sunday, April 01, 2012 22:21 > To: DK Duncan; [email protected] > Subject: Re: [altusmetrum] Telemini mach delay/kalman filter > > <#part sign=pgpmime> > On Sun, 01 Apr 2012 20:18:12 -0700, DK Duncan <[email protected]> > wrote: > > > Right, but the telemetrum has an accelerometer as well as a pressure > > transducer. > > TeleMetrum logs all of its raw sensor data, which means we can use that to > check the algorithms on the ground. We used all of this data to verify that > the Kalman-filter based mach-inhibit algorithm correctly detects when the > airframe is experiencing mach transition effects. > > So, in effect, "TeleMini" has flown faster than mach dozens of times, but > the code was run on recorded data and not in actual flight. > > What the flight computer does is compare the barometric data with the > obvious physics model for a rocket in ballistic flight by looking at the > error term in the Kalman filter. When they agree, the computer arms the > apogee charge. When they don't agree, the altimeter inhibits the apogee > charge. This error term varies by a factor of 100 between ballistic and > non-ballistic flight, which gives us a strong signal for this technique. > > > I'll be pushing mach 1.5 this summer and I want redundant altimeters. > > The telemini should be a good way to do that provided it will handle > > mach transitions well. > > > > I'm hoping someone here has tested it in flight at those velocities. > > I've got two near mach flights, one to 317m/s (as measured by Tm), and one > to 325m/s (as simulated; the rocket was lost due to a power failure at > apogee). Tm worked flawlessly in both cases. > > We'll be doing a more testing this year, to see if there's any issue with > the Kalman filter not detecting mach transitions correctly. I just need to > make some time to build more little airframes for testing with TeleMini > hardware. > > We could obviously add a mach delay setting to Tm's configuration; I > suspect > it might make people more comfortable than trusting some fancy computer > software. > > -keith > _______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum > > _______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum > >
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