I am working on my 10th grade science fair project which is a "Semi-Autonomous Payload Retrieval System." The basic idea is to have a multirotor receive GPS data from a transmitter in the payload and fly to its location. The transmitter that is in the payload transmits using a 915mhz Xbee that is paired to another Xbee on an Arduino shield mounted on the multirotor. The Arduino receiver will take the GPS data from the payload and put it in a MAVLink way-point packet and give it to the autopilot. I would like to be able to run the Arduino receiver in tandem with the 3DR telemetry radio so that i can keep tabs on the multirotor while it is flying a mission (I use the 915mhz telemetry radio, i know there could be some interference, if that turns out to be a problem i will get a HAM license and switch to 433mhz.) The problem that I am running into is that there is very little documentation on the format of MAVLink packets and how to send/receive them. I have scene a few projects that do this but they haven't had any code that shows the process of formatting or sending/receiving the packets. I have also found this tutorial but the link to the code library that supposedly fixes a compiling issue is a dead link.
If anyone knows how to make the linked tutorial work, have knowledge in MAVLink coding, or can point me in the right direction, a comment would be appreciated. Thanks.