Doubts on Implementing a Simple Protocol for XBee Comms
I'm going to be using Xbee modules. I'll be trying to use a point to multipoint network.

At the moment, I plan to have a transmitter identifier, payload type, payload length, payload and checksum - it would look something like this:

Field            Type    Description   
transmitter_id   uint8   Identifies the transmitting module (0-255)
type             uint8   Type of data (GPS coordinates, hit status, etc.)
length           uint8   Length of payload in bytes
payload          -       Actual payload
checksum         uint16  CRC16 of everything before


That's how I imagine it, the format might change but this will be the basic protocol in use.