Control Architecture and Sensor Fusion

Hey,

I’m trying to figure out how the sensor information from the accelerometer, gyroscope, gps, etc. are used along with the low level control architecture. I’m basically trying to figure out how the sensor information is used to control a given UAV. Any reading material?

I’m trying to figure out the Pixhawk source code. Where can I find information on the variables used throughout the firmware, as in what variables are used for storing what data?

Also does anyone have access to the EKF Thesis pdf in its entirety?

Does anyone have the expertise to help me out?

Thanks

Akshay