Work with specific variables within the open source ArduPilot code base

This should be a quick project for a knowledgeable C++ programmer. ArduPilot is an open source code base for autonomous vehicle control using processors such as, in this case, STM32F4 and various sensors, with drivers and HAL already built. There are several sensor matrices and variables which reside within libraries in the ArduPilot code base which this project will use to effect actions which are not currently available within ArduPilot. Some of the needed code is already written by an amateur C++ coder, but help is needed calling certain functions and variables from the libraries appropriately. Preference will be given to C++ coders with prior knowledge of the ArduPilot code base. Please explain your familiarity level with this code base as well as any prior work you have done within this code.