Howdy
I am working on a data logger/controller (staging,chute deployment,ETC) for a high power bird. I have the payload section designed and building a prototype. I need help in designing the ground unit. I need a computer that passes the bird logger’s USB (through a umbilical) to a laptop USB. Here lays the area I need help with. This ground unit monitors the USB traffic for commands. The command string looks like "[||Command||]. These commands allow the birds logger to control the arming and launching of the bird. The way I think (oh what ahead ache) it can be done, when a USB receives a charter (either laptop to logger or Logger to laptop) if it is not the beginning control charterer then is passed on to to the device. Laptop to logger or logger to laptop. When the command string is received it’s decoded to do what is required (like turning on a relay to launch the bird). The functions I can handle with very little effort. It’s the USB handling I am having trouble with and in need for help.
Then once I debug the sketch, I need to write the code in to the bootloader so when it powers up it’s ready to do it’s thing. I have been looking at the Installing an Arduino Bootloader tutorial. I think beyond febel mind. So I will need help when I get to that point in this project.
Any question please feel free to ask. 
Rocket nut