Building pixhawk firmware directly and getting RTK data directly

Hi my name is Sangjin Pyo in South Korea.

I have developed package delivery system by using drone which uses pixhawk as its controller

and because accurate landing information is very important for this project, I ordered Emlid RTK kit yesterday to use it for my work.

My first question is…
"Is there firmware open source code for Pixhawk controller?"
At EMILID documentation site, I checked they provided ERB Firmware(Binary form) for Pixhawk user.
But because this firmware file is provided as a fixed binary form, it is impossible to analyze it as c source code format.
For my project, I need to develop source code directly and It seems there is not Pixhawk firmware which is provided as source code format.
I also checked Rtklib, but hard to find any clue

My second question is …
"Is it possible to get RTK Reach data directly as LLH form from Reach module to Pixhawk without ERB protocol?
because my working environment is Ubuntu 14.04, I wonder without using Mission Planner if it is possible to get RTK Reach data directly from Reach module to Pixhawk controller in Linux terminal.

Any comments will be very appreciated for me.
Thank you~~~

Hi,

ERB protocol support has been merged in ArduPilot in March. Arducopter 3.4-rc2 already has support for Reach ERB protocol.