[Paparazzi-devel] Telemetry Protocol

[Charles Breingan]

I am trying to create an alternative method of controlling an autopilot other than the primary ground station. In doing this I need to spoof some messages as it if were from the ground station across the XBee link.

The protocol for the air-ground communication is easy enough to figure out from the documentation. However, I can't seem to figure out the protocol for ground-air communication. I've logged the data being sent, and it doesn't seem to make any sense. Lots of 0x5E and 0x08 being sent. But no repeatable pattern that I can see. It definitely doesn't look like the message format that the aircraft sends back to the ground.

All I need to do is spoof the "jump to block" message and send it from another XBee separate from the GCS. I thought that this message would be 0x99 08 00 1B 02 02 24 79. But this is not working at all. 

Any thoughts would be greatly appreciated. Thanks.

Sincerely,

C. Randy Breingan