Anthony Kremor <[email protected]> writes:

> Finally got around to giving my Telemetrum its maiden flight. I would like
> to say everything went well, but it did not. The dangers of using older
> motors.

Sorry to hear about your adventures...

> Based on the data file attached, I believe that the ejection charge did not
> fire and the rocket came down ballistic. I also believe that the last
> reported GPS co-ordinates were obtained shortly before impact, so you would
> expect that I would have been able to find it.

Yeah, a classic ballistic flight. Afraid I've seen a few of those graphs
with my own airframes...

I've converted the provided telemetry file into a KML file and am
looking at that with Google Earth. That says you launched from the
middle of Moylan Road, and that the rocket went essentially straight up
and came straight back down, landing SE of the launch site, about 15m
south of the road (about 20m from the launch site).

The last reported location was S 36° 19.6533' E 145° 37.5005'

You also have a very strong signal for those last few packets,
re-enforcing the notion that the rocket landed very close to the
receiver.

It's also possible that the GPS receiver was just confused; with a low
flight, there isn't always time for it to catch up after boost. That's
because the raw GPS position data (which shows 11 sats in solution) gets
fed into a Kalman position filter, and that really doesn't understand
vertical acceleration. The fact that the GPS reported altitude is at the
ground for the whole flight tends to support this possibility.

> I end up manually parsing the last lines of the file, and somehow came up
> with a different set of GPS co-ordinates than were outputted by AltOSui. I
> am not sure if this is due to an issue with my parser.

The current AltosUI has some additions to the 'graph' mode which shows
the last reported position, provides a map of the flight and allows you
to graph lots more values (including GPS sat coverage, telemetry RSSI
and more)

> Does anyone mind having a look at the attached file and provide any
> insights into where it may be, as it's is practically impossible to get
> another right now. Best wishes to the operators with their rebuild.

We're hoping to begin test flights for TeleMetrum v2.0 along with lots
of other new stuff next weekend at Airfest in Kansas. All of the new
stuff will be using u-blox GPS chips that offer fabulous performance for
tracking rockets. Early tests with these chips showed that they will be
capable of detecting apogee accurately enough for deployment at
altitudes above the range of our barometer.

-keith

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