Re: Changed the subject back to APRS :)

Leo Bodnar <leo@...>
 

James,

This is correct, the onboard flight data recorder has the circular buffer containing 64 entries spaced at 2 hour intervals which equates to just over 5 days.

The content of the data log is continuously transmitted together with current data via APRS.

Looking at the raw sentences you will notice that some of them are longer - they contain log data in the comment field.

E.g. in these two lines 

M0XER-3>APRS63,WIDE2-1,qAR,VE7AV-4:!/4%r2/6]DO J^;I/A=041200|k2RU(8?0!(|
M0XER-3>APRS63,WIDE2-1,qAR,VE7AV-4:!/4%\6/6akO J^;^d!J[o$6,cV.[%8FNJ`_O@1/A=041177|k3RW(=?.!(|

second one contains extra base-91 encoded log data  ...d!J[o$6,cV.[%8FNJ`_O@1...

I am running the script that looks at aprs-is traffic and catches everything that M0XER-3 sends.  It decodes current and backlog data and sends it to spacenear.us
Current data transmitted with receiver tag "APRS" and historical with a tag "LOG"

After decoding the two packets above become...

1st packet:
$$B-63,6751,213550,140722,52.3066,-123.6668,12558,7,1,4.51,0.66*BAE3
2nd packet:
$$B-63,6752,213611,140722,52.3119,-123.6646,12551,7,1,4.51,0.66*4380 - current position 
$$B-63,6097,160002,140722,48.2015,-126.0414,12550,11,10,4.31,0.56*3B75 - historical position from earlier today

Note that all three records have embedded exact timecode of actual position sample and not when aprs-is has received it.
Looking carefully at the packets you will notice J^;I and J^;^, they are decoded into July 22nd 21:35:50 and July 22nd 21:36:11 respectively.

Cheers
Leo



On 22 Jul 2014, at 22:31, James Ewen ve6srv@... [GPSL] wrote:

 

Anthony,

Do you have any insight into the different receivers being listed at
spacenear.us?

We saw M0XER-3 pass over Alaska yesterday via APRS, and then go dark
until being picked up again off the coast of Washington this morning.

When looking at the spacenear.us tracking page We can see the full
track from Siberia through to current.

In areas where APRS wasn't present, the data points are further apart,
and the site reports the location receiver as LOG.

Does the payload store tracking data while in flight, and download the
stored information somehow to the network, and into spacenear.us?

--
James
VE6SRV


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