QGroundControl (QGC) is a full-featured ground control station for unmanned aerial vehicles (UAVs) that communicates over the MAVLink protocol. It provides real-time telemetry display, mission planning with complex survey/scan patterns, video streaming with hardware-accelerated decoding, GPS/RTK correction management, and vehicle configuration for PX4 and ArduPilot autopilots. The application is built as a cross-platform Qt/QML desktop and mobile app, with a plugin architecture for firmware-specific behavior, a custom state machine framework for workflow orchestration, and a Fact system for type-safe parameter binding to the QML UI. Key entry points include the main application bootstrap (src/main.cc), the MAVLink protocol handler, the GPS manager, the video pipeline, and the mission controller. External dependencies include Qt (Quick, Positioning, Multimedia, State Machine), GStreamer for video, MAVLink C library, and various GPS protocol libraries. The repository also contains extensive CI/CD infrastructure, Docker build environments, and a comprehensive test suite with mock links and golden transcript testing for GPS protocols.
Flix is an open-source ESP32-based quadcopter project built from scratch. The repository contains flight controller firmware, a Python control/telemetry library, C++ utilities for log conversion, simulation assets, and extensive documentation. It is primarily an application repo, though it also includes CAD models and data-conversion tools that serve as supporting assets. At runtime, the ESP32 firmware reads IMU data, estimates attitude, and drives motors, communicating via MAVLink and ESP-NOW for telemetry and control. The Python library (tools/pyflix/flix.py) provides an observable API for interacting with the vehicle, and CLI tools convert flight logs from CSV to MCAP and ULog formats for analysis in standard robotics tooling. A Gazebo simulation and a Python test harness validate behavior without hardware. Architecture is a multi-part monorepo: firmware, Python tools, C++ tools, docs, and 3D-printable mechanical parts. External dependencies include the Arduino ESP32 core, MAVLink, ESP-NOW, Gazebo, and custom math classes. The code is generally well-structured, but some data flow relies on global variables and hardware-specific assumptions, limiting reuse outside the ESP32 ecosystem. The project appears actively maintained with CI workflows, but dependency pinning and tight hardware coupling create moderate drift risk.