> On 17 Sep 2020, at 12:41 pm, Bdale Garbee <[email protected]> wrote: > >> I too had a flight last year that the telemetry (TeleMega) went dark at >> apogee (37500'). Is is possible to have the firmware save the state of >> the flight so it can get back to where it needs to be after a brownout? >> I would think that having a quick read of the baro sensor will tell you >> it is in flight and needs to be dealt with differently than when on the >> ground. There are likely many other methods that could be used. It >> might be useful to write the current state at time intervals to EEPROM >> or FLASH, and perhaps also before triggering pyro event. > > That's not a bad idea, but there are a pile of subtleties we stumbled > over when we last thought about it. I'll talk to Keith about it and see > if we can find a way out of the swamp here.
Hmm, if the issue is the GPS loses power and needs to do a cold start, then you may still hit the ground before there’s any chance of lock. I guess a very rough approximation may be if the Kalman filter could keep guesstimating location without the GPS lock, but it would also need to work out how much time has passed since the last saved state that was recovered before the brownout/disconnect and then try and to ‘catch up’ based on current sensor data? It could then possibly report its ‘estimated’ position while having 0 satellites in view, hence highly unreliable. I guess bottom line, is to reduce the chance of brown out and thus remove the need to try and do a lot of complicated calculations that would be highly questionable. That said, for something that’s completely out of view, anything is likely better than nothing, but could just as well be wasting your time searching an estimated area that is completely wrong.
_______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
