UNIT-4
1. Sensor Calibration
Sensor calibration is essential for accurate data acquisition and reliable UAV operation. It
corrects sensor errors and ensures precise measurements.
Key Sensors in UAVs:
IMU (Inertial Measurement Unit): Measures acceleration, rotation, and
orientation.
GPS (Global Positioning System): Provides accurate location and positioning
data.
Magnetometer: Measures the Earth's magnetic field for directional accuracy.
Barometer: Measures atmospheric pressure to calculate altitude.
Gyroscope: Detects angular velocity for stability and orientation.
Calibration Techniques:
Offset Correction: Adjusts for static biases in sensor readings.
Scale Factor Adjustment: Corrects measurement scaling errors.
Environmental Calibration: Accounts for temperature, humidity, and pressure
variations.
Real-Time Calibration: Continually adjusts during flight for dynamic changes.
2. Tracking Using GPS
GPS is vital for UAV navigation and positioning, enabling both manual and autonomous
flight.
Features of GPS Tracking:
Real-Time Positioning: Continuous tracking of UAV location.
Waypoint Navigation: UAV follows pre-defined GPS coordinates.
Geofencing: Restricts UAV movement within set boundaries.
RTK (Real-Time Kinematic) GPS: Provides centimeter-level accuracy for
precision tasks.
Challenges in GPS Tracking:
Signal Loss: In urban areas or under dense foliage.
Jamming/Spoofing: Security risks affecting navigation.
3. UAV Stability
Stability ensures smooth and controlled flight, reducing the risk of crashes.
Types of Stability:
Static Stability: Ability to return to the original position after a disturbance.
Dynamic Stability: The UAV's capacity to dampen oscillations over time.
Factors Affecting Stability:
Center of Gravity (CG): Proper weight distribution prevents instability.
Aerodynamic Design: Streamlined structures reduce drag and turbulence.
Control Algorithms: Flight controllers stabilize motion via sensors.
4. UAV Controllability
Controllability refers to how easily the UAV responds to user inputs or automated
commands.
Control Mechanisms:
Manual Control: Pilot-operated via remote controllers.
Assisted Control: Flight controllers provide stabilization support.
Fully Autonomous Control: UAV operates without pilot input.
Key Components:
Flight Controller: Processes sensor data and adjusts motor speeds.
ESC (Electronic Speed Controllers): Regulates motor power.
Control Surfaces: Ailerons, rudders, and elevators on fixed-wing UAVs.
5. Flight Control
Flight control systems ensure the UAV performs safe and accurate maneuvers.
Components of Flight Control Systems:
Primary Control System: Adjusts orientation (pitch, roll, yaw).
Secondary Control System: Manages altitude, speed, and stability.
Telemetry Systems: Communicates data between UAV and Ground Control
Station (GCS).
Control Loops:
Open-Loop Control: No feedback; relies solely on input commands.
Closed-Loop Control: Feedback-driven for adaptive corrections.
6. Autonomous Control
Autonomous control allows UAVs to execute missions without real-time human
intervention.
Features:
Pre-Programmed Routes: UAV follows pre-set waypoints.
Obstacle Avoidance: Uses sensors (LiDAR, ultrasonic) to detect and avoid
obstacles.
Automatic Takeoff and Landing: Reduces pilot workload.
Mission Adaptability: Real-time adjustments to environmental changes.
Advantages:
Increased efficiency in complex missions.
Reduced human error.
7. Semi-Autonomous Control
Semi-autonomous control blends human input with automated systems.
Features:
Pilot Assistance: UAV manages stability, but the pilot controls navigation.
Emergency Override: Pilot can regain control during system failure.
Flexible Operation: Suitable for tasks requiring both automation and human
judgment.
Applications:
Aerial Photography: Automated flight with manual camera control.
Surveying: UAV follows a path, but operators can adjust for anomalies.
Assignment:-
1. Explain the process of Sensor Calibration in UAVs. Discuss why it is essential and
describe different methods used for calibrating various sensors used in UAVs.
2. Discuss Tracking using GPS in UAVs. Explain how GPS data is processed for real-
time tracking and navigation. What are the limitations of GPS tracking in UAV
operations?
3. Compare and contrast UAV Stability and UAV Controllability. How do these concepts
impact the performance and reliability of UAVs during flight?
4. What is Flight Control in UAVs? Discuss the role of control systems in maintaining
stability and executing flight maneuvers. Include examples of control algorithms used
in UAVs.
5. Differentiate between Autonomous Control and Semi-Autonomous Control in UAVs.
Describe their advantages, disadvantages, and applications in various scenarios.
