How does GPS stream over serial?

Hi, I am working on a project that requires me to be able to send GPS locations to my Pixhawk-- i.e. use our indoor motion capture system to send the autopilot positional data, so we can fly indoors.

My approach is to have GPS packets streaming over Xbee, then connect the Xbee to the GPS port, so the pixhawk thinks it is just receiving data from the GPS (not requiring firmware changes, etc) .

I am having trouble generating the GPS strings-- Does anyone know how the GPS sends its data over serial? Is it just one character at a time, looping over the current message? I have my pixhawk set up to listen to NMEA messages and using PyNMEA2 in python to generate the GPS strings and send them over Xbee. Currently it just says no satellites, no lock, etc.


Are you try to make it think it’s somewhere it’s not? I suppose if you are using motion capture to get a true position and calculate the offset you could do that. It might be better to ask this question on the drones-discuss Google group

Yep… I am trying to use motion capture to fly it indoors.

From my experience the drones-discuss board contains the people who can help these types of issues but just push you back to this forum unless you ask about some bug.