Reference Design
UAV Flight Control System
A complete reference design for building production-ready unmanned aerial vehicles with autonomous flight, advanced navigation, and payload integration for commercial and industrial applications.
Introduction
What This Reference Design Is About
This UAV reference design provides a complete blueprint for developing production-ready unmanned aerial vehicles for commercial, industrial, and defense applications. It demonstrates our proven approach to achieving reliable autonomous flight while enabling sophisticated mission capabilities.
The design covers flight control, navigation, obstacle avoidance, and payload integration—enabling complex autonomous missions with fail-safe operation and regulatory compliance.
Requirements
- Flight Stability: Attitude control with <1° accuracy in wind gusts
- Navigation: RTK GPS with cm-level positioning accuracy
- Safety: Multiple redundancy with automatic fail-safe modes
- Communication: Encrypted telemetry with 20km+ range
- Autonomy: BVLOS capable with detect-and-avoid
Recommended Architecture
Distributed flight control architecture with separation of flight-critical and mission functions:
- • Flight Controller: Real-time attitude stabilization and low-level control
- • Mission Computer: Path planning, obstacle avoidance, and autonomy
- • Payload Controller: Camera gimbal and sensor management
- • Communication Module: Telemetry, command, and data links
- • Power System: Battery management with flight time estimation
Essential Parts of This Design
- • Attitude and position control with sensor fusion
- • GPS/INS navigation with RTK support
- • Computer vision for obstacle detection
- • Autonomous waypoint and corridor flight
- • Multi-rotor and fixed-wing support
- • Encrypted command and telemetry links
- • Geofencing and airspace compliance
- • Ground control station integration
This reference design serves as a customizable foundation—adapt it to your specific airframe, payload, and mission requirements.
Hardware
Recommended Platform: Arches + Pinnacle
Hybrid Platform: Arches (Jetson) for AI/vision + Pinnacle (i.MX) for flight control
Why This Combination:
- • Arches: GPU for computer vision and obstacle detection
- • Pinnacle: Real-time capable with low power consumption
- • Clean separation for safety certification
- • Optimized SWaP (Size, Weight, and Power)
Alternative: For smaller UAVs, Pinnacle alone with NPU for limited AI capability
Essential Components to Add
Components added to baseline platforms:
- • IMU: Redundant MEMS IMU (Bosch BMI088 or ADIS16470)
- • GPS/GNSS: u-blox ZED-F9P with RTK capability
- • Barometer: Dual barometers for altitude sensing
- • Magnetometer: Triple-axis compass with calibration
- • ESC Interface: PWM/DShot for motor control
- • Radio Modem: Digi XBee or Microhard for telemetry
- • RC Receiver: SBUS/PPM for manual override
Schematic Capture & PCB Layout
Design Tools: Altium Designer with aerospace component libraries
PCB Stack-up: 6-layer with ground planes for EMI immunity
Key Considerations:
- • Vibration isolation for IMU mounting
- • Magnetic isolation for compass placement
- • Power distribution for motor transients
- • Conformal coating for environmental protection
Regulatory Requirements
Aviation Standards:
- • DO-178C for airborne software (DAL C/D)
- • DO-254 for airborne hardware
- • STANAG 4671 for military UAS
Airspace Compliance:
- • Remote ID broadcasting (FAA/EASA)
- • ADS-B out for controlled airspace
- • Geofencing for no-fly zones
EMC: DO-160G for airborne equipment
RTOS/Operating System
Recommended: RTOS + Linux Hybrid
NuttX RTOS for flight control + Yocto Linux for mission computer
Flight Controller (Pinnacle) - RTOS:
- • NuttX RTOS (PX4 compatible)
- • Deterministic 400Hz control loops
- • Direct sensor and actuator access
Mission Computer (Arches) - Linux:
- • Yocto Linux with real-time kernel
- • Computer vision and AI inference
- • Mission planning and data processing
Why Both Are Needed
RTOS Required For:
- • Flight-critical attitude control (400Hz)
- • Sensor fusion with guaranteed latency
- • Fail-safe operation independent of mission computer
- • Certification pathway (DO-178C)
Linux Required For:
- • Computer vision and deep learning
- • Complex path planning algorithms
- • Payload data processing
- • Cloud connectivity
Interprocessor Communication
Communication Protocol:
- • MAVLink v2 over UART/UDP for standardized messages
- • High-speed serial for sensor data streaming
- • Heartbeat monitoring for health checks
Fail-Safe Design: Flight controller operates independently if mission computer fails—automatic return-to-home triggered
Kernel & Driver Configuration
NuttX Configuration:
- • PX4 flight stack integration
- • uORB messaging for internal communication
- • DMA for sensor data acquisition
Custom Drivers:
- • IMU driver with temperature compensation
- • GPS driver with RTCM correction
- • ESC driver (DShot/PWM)
- • Radio modem driver with encryption
Middleware
Recommended Middleware: MAVLink + DDS
MAVLink v2 for flight systems + DDS for mission applications
Why This Combination:
- • MAVLink: Industry standard for UAV communication
- • Lightweight protocol for bandwidth-limited links
- • DDS for high-bandwidth sensor data on mission computer
- • ROS 2 integration for autonomy stack
Regulatory Considerations
Communication Security:
- • MAVLink v2 signing for command authentication
- • AES encryption for telemetry data
- • Frequency hopping for interference resistance
Airspace Integration:
- • Remote ID broadcast protocol
- • UTM (UAS Traffic Management) integration
- • ADS-B transponder interface
Middleware Interfaces
Flight Interface:
- • Attitude and position setpoints
- • Mission waypoint upload
- • Flight mode commands
- • Emergency commands (RTL, land)
Telemetry Interface:
- • Vehicle state (position, attitude)
- • Battery status and flight time
- • System health and diagnostics
- • Sensor status and calibration
Payload Interface:
- • Gimbal control commands
- • Camera trigger and settings
- • Video streaming configuration
- • Sensor data recording
Application
Application Architecture
PX4 Flight Stack on RTOS + Custom autonomy on Linux
Architecture Pattern: Modular with clear separation between flight-critical and mission functions for safety certification.
Design Decision: C++ for real-time flight control, Python for mission scripting and testing.
Core Application Modules
- • Flight Controller: PX4 with custom control modes
- • Navigation: EKF2 sensor fusion with visual-inertial odometry
- • Path Planner: A* and RRT* for obstacle-aware paths
- • Detect-and-Avoid: Computer vision for obstacle detection
- • Mission Manager: State machine for complex missions
Development Tools
Essential Tools:
- • PX4 development environment
- • Gazebo for SITL simulation
- • QGroundControl for configuration
- • Flight review for log analysis
Testing Tools:
- • Hardware-in-the-loop (HITL) simulation
- • MAVSDK for automated testing
- • Indoor positioning for GPS-denied testing
Diagnostics & Security
Log Management & Debugging:
- • ULog for flight data recording
- • Post-flight analysis with Flight Review
- • Real-time parameter tuning via MAVLink
OTA & Security:
- • Secure boot with hardware root of trust
- • Encrypted firmware updates
- • Geofencing enforcement
Other Essential Supporting Apps
Cloud Integration
- • Fleet Management: Multi-UAV tracking and coordination
- • Mission Planning: Cloud-based flight planning with airspace checks
- • Data Processing: Automated orthomosaic and 3D model generation
- • Telemetry Storage: Flight data archive for analysis and compliance
Desktop Applications
- • Ground Control Station: Mission planning, monitoring, and control
- • Flight Review: Post-flight analysis and PID tuning
- • Sensor Calibration: IMU, compass, and camera calibration tools
- • Firmware Manager: Version control and update deployment
Web-Based Apps
- • Flight Planning: Web-based mission design with 3D visualization
- • Live Dashboard: Real-time fleet status and video streaming
- • Data Portal: Mission data access and sharing
- • Compliance Reporting: Automated flight logs for regulatory submission
Our Experience
Products Delivered
Using this reference design, we have successfully delivered:
- Agricultural Drone: Fixed-wing UAV for crop monitoring with multispectral imaging and BVLOS capability
- Inspection Drone: Quadcopter for infrastructure inspection with obstacle avoidance and autonomous inspection
- Delivery Drone: Heavy-lift hexacopter for last-mile delivery with precision landing
Key Achievements
±2cm
RTK Positioning
60min
Max Flight Time
BVLOS
Certified Operation
20km+
Communication Range
Our UAV reference design has been deployed in agriculture, infrastructure inspection, surveying, and logistics applications.