glidernet / ogn-tracker Goto Github PK

I am searching an official specification for the ogn packet and there I found the wiki and the ogn.h file in this repository.
It seems that the wiki is anymore up to date.

Wiki: http://wiki.glidernet.org/ogn-tracking-protocol
Code: https://github.com/glidernet/ogn-tracker/blob/master/ogn.h#L125

https://github.com/glidernet/ogn-tracker/blob/master/ogn.h#L28
It should be "FBDD" according to the comment next to it

We need to store:
Address: 24 bits
ICAO flag: 1 bit (if the above address is ICAO assigned)
Aircraft type: 4 bits
Private/visibility flag: 1 bit
This data could be combined in one Acft_ID 32-bit word, like we do already in OGN

Address could be as well generated from the 96-bit unique CPU ID.

Would be good to provide calls to read the Acft_ID from any task
and commands in the console to store this data.
As well a call to read the unique ID is needed and an algorith to convert it to 24-bit address.

could be done by switching between several standard rates as long as no valid NMEA frames are detected. Once the NMEA frames start arriving the speed should stay.
Algorithm is easy and should achieve correct speed within 10-20 seconds.

It can be very convenient, as one needs not to check eveyr time if the GPS speed matched the configured tracker speed.

Example Condor NMEA output:

$GPGGA,120009.136,4621.5849,N,01410.2437,E,1,12,10,504.7,M,,,,,0000_00
$GPRMC,120009.136,A,4621.5849,N,01410.2437,E,0.00,134.00,,,,_20
$LXWP0,Y,0.1,504.7,0.00,,,,,,134,351,19.5*71

It looks like there is height of geoid and date missing.

Transmission of packets should be synchronized to PPS signal from the GPS.

It is an open question, if the GPS can transfer the data fast enough so that the position can be transmitted in same time-slot or otherwise it should wait for the next time-slot.